Vegetables & Fruit July/August 2024

SINCE 1988

JULIE • AUGUSTUS 2024

Keeping Citrus exports to India deciduous trees face challenges free from scheme viruses ingesluit) ander lande uitgesluit (Including VAT) other countries excluded No 220 R47,00 (BTW

EXPLORING THE SWEET PEPPER SPECTRUM DIVA

DUKE

• Harvestable at green and yellow stages • Uniform, high-quality blocky fruit • Sets fruit well under diverse environmental conditions • High resistance to Tobamo viruses (Tm:0-2) • Intermediate resistance to Tomato Spotted Wilt Virus (TSWV:0)

• Harvestable at green and red stages • Slower fruit maturity allows for extended green harvesting periods • Strong plant with good leaf cover • Large fruit with thick walls • Intermediate resistance to Phytophthora capsici (Pc) and Bacterial Leaf Spot (Xcv:1-3)

YELLOW DIAMOND*

NEW

• Ideal for indoor production • Harvestable at green and yellow stages • Uniform, high-quality blocky fruit • Sets fruit well under diverse environmental conditions • High resistance to Tobamo viruses (Tm:0-3) • Intermediate resistance to Tomato Spotted Wilt Virus (TSWV:0)

ZIA*

NEW

• Harvestable at green and yellow stages • Uniform, high-quality blocky fruit • Consistent fruit set under various environmental conditions • Maintains shape and size throughout the growing cycle • High resistance to Tobamo viruses (Tm:0-3) • Intermediate resistance to Tomato Spotted Wilt Virus (TSWV:0)

PFEIFFER • Harvestable at green and red stages • Strong plant with good leaf cover • Uniform, high-quality blocky fruit with thick walls • Resistance to powdery mildew • High resistance to Tobamo virus (Tm:0) and Bacterial Leaf Spot (Xcv:0-3,7,8) • Intermediate resistance to Tomato Spotted Wilt Virus (TSWV:0), Powdery Mildew (Lt), and Phytophthora capsici (Pc)

MARX • Green to red blocky sweet pepper • Uniform, large, high-quality fruit • Sets fruit well under cool conditions • High resistance to Tobamo virus (Tm:0), Bacterial Leaf Spot (Xcv:0-5,7,9), Pepper Mottle Virus (PepMoV), Potato virus Y (PVY:1), and Tobacco Etch Virus (TEV) • Intermediate resistance to Cucumber Mosaic Virus (CMV) and Phytophthora capsici (Pc)

NEEM KENNIS TAKE NOTE Weens afleweringsprobleme met die gewone posdiens word intekenare en lesers versoek om hul e-posadresse aan info@mediakom.co.za te stuur vir die elektroniese versending van GROENTE & VRUGTE - VEGETABLES & FRUIT.

Edition 220

ISSN 1015-85 37

www.vegetablesandfruitmagazine.co.za

COVER Bigbucks, the improved Gala apple mutation from South Africa, is known for it's beautiful wine-red colour.

Due to delivery problems with traditional mailing services subscribers and readers are requested to send their e-mail address to info@mediakom.co.za for electronic delivery of VEGETABLES & FRUIT GROENTE & VRUGTE.

EDITORIAL Willie Louw (Group editor)

8-9

NUUS NEWS

Carien Daffue (Editor) 082 927 8294 018 293 0622 info@mediakom.co.za PO BOX 20250, Noordbrug, 2522 ADVERTISING Jana Greenall 011 476 3702 082 780 9914 mediacom@lantic.net DESIGN Mercia Venter studio.chatnoir@gmail.com

NEWS 4

Secure bag closing for export of agricultural product

4

Olive trees planted at Mardouw

5

Shell commits to sustainable agriculture

5

‘Emerging farmers to insure their operations’

6

SA to feed an additional four million people by 2030

8

Cases against EU citrus measures move forward at WTO

9

Mozambican citrus growers join the CGA

9

SA Star Ruby export forecast adjusted downward again

16 20

DECIDUOUS FRUIT Besoek ons webtuiste | Visit our website:

10

Vergelegen shares lessons on combating grapevine leafroll disease in vineyards

12

Pieter du Toit awarded frontrunner award

14

South African Bigbucks apple granted plant breeders’ rights in Australia

16

Keeping deciduous trees free from scheme viruses

www.vegetablesandfruitmagazine.co.za

Bly ingelig en volg ons op Facebook.

Keep up to date and follow us on Facebook.

Groente & Vrugte | Vegetables & Fruit www.facebook.com/SAGroenteenVrugte

SUBSCRIPTIONS Available on subscription only - visit website: Slegs met intekening beskikbaar - besoek webblad: www.vegetablesandfruitmagazine.co.za 1 Year @ R250.00

2 Years @ R475.00

(6 issues)

(12 issues)

VAT included In case of address change, please quote or attach previous address label Special rates for group subscriptions

26

PEPPERS 18

Resilient greenhouse varieties: A solution to powdery mildew in sweet pepper plants

GENERAL 20

Physiological disorders in cucumbers under protection

22

Plaagbeheer en risikobestuur

24

Vyeroes onder die soeklig

26

Crop4Life enhances the uptake of calcium in oranges and mandarins

VEGETABLES & FRUIT | JULIE • AUGUSTUS 2024

3

NUUS NEWS

NEWS

Secure bag closing for export of agricultural product A

bag closing company was able to find solutions for efficient packaging of pecan nuts destined for export while upholding health and safety standards.

An agricultural wholesaler from the Northern Cape recently asked Buckle Packaging to help streamline operations at their plant. The client needed to expand their production capabilities to accommodate growing demands in the export market.

The ideal solution was to put in two new lines for securely and efficiently packaging 25 kg poly woven bags of pecan nuts. An essential requirement was to find the right equipment to uphold their prestigious health and safety standards.

Buckle Packaging is a Johannesburg-based, specialist bag closing company that has successfully found solutions for businesses since 1979.

“We recommended the Fischbein MP100 stitching machine, as this is the only bag closing machine that would maintain the client’s brand image while providing them with the best securely and neatly stitched bag every single time,” explains Matthew Mason, Marketing Manager for Buckle Packaging.

At the same time, Buckle Packaging installed two 3,3 meter conveyors that allowed the stitching machines to operate more efficiently, saving time and money and protecting operators from deadline stresses.

Mason continued saying that the equipment was delivered,

Fischbein auto bag stitcher MP100.

off-loaded and set up in 40 minutes. Buckle Packaging provides an after-market service which includes servicing and machine repair should it be required. They also offer a range of quality spare parts and peripherals, including stitching threads.

Buckle Packaging’s extensive knowledge and experience have been built up over more than 40 years. They offer tailored solutions to meet clients’ specific needs and import the best performing packaging equipment from around the world to ensure minimal downtime and increased productivity.

Olive trees planted at Mardouw T

he Verder Group, a global technology group, recently planted 2 000 olive trees at the award-winning Mardouw Olive estate, in Swellendam in the Western Cape, as part of their environment and social responsibility program, each olive tree representing one of their employees.

A ceremony to mark the occasion, held recently at the Estate, was attended by Cape Town Executive Mayor, Schalk van Eeden, Richard Hattersley, MD Of Verder Scientific SA, Nina Verder representing the Verder family, and Mardouw Executive Chairman, Gerbrand Nijman.

“This signifies our commitment to sustainability and our belief in the power of collective action for the greater good,” said Hattersley. “In partnership with Mardouw Olive Estate, one of South Africa’s premier producers of quality extra virgin olive oil, this project symbolises our dedication to reducing our ecological footprint. And we have planted more than 2 000 trees here at Mardouw because we are always expanding, and we will soon have more than 2 000 employees.”

Mardouw’s Gerbrand Nijman said the trees will contribute to a better environment. “We will take pride in taking good care of these trees – which will, of course, contribute to making more of our award-winning extra virgin olive oil.

4

VEGETABLES & FRUIT | JULY • AUGUST 2024

As South Africa’s most decorated olive oil brand, our high standards of high quality have been – like Verder Group’s – recognised worldwide, as evidenced by our platinum and gold awards not only in South Africa but also in Europe, the USA, and South America. It will be our honour to nurture these trees.”

SA Olive Industry Association CEO Wendy Petersen is delighted by the news. She said the planting of new olive trees is a fantastic initiative with numerous long-term benefits for the industry. Olives are traditionally grown in a Mediterranean-type climate, which is why 95% of land under olive cultivation in South Africa is located in the Western Cape.

“There is a worldwide demand for excellent olive oils and table olives; meeting this demand through increased production can be highly lucrative. Beyond the economic benefits, planting olive trees is crucial for sustainability and environmental stewardship. This initiative has significant social implications, particularly in terms of job creation. Planting, cultivating, and harvesting olives provides numerous employment opportunities. This project is a wonderful turnkey solution, offering a comprehensive approach to long-term sustainability.”

NUUS NEWS

NUUS

Shell commits to sustainable agriculture JENNIFER ROETS CONTRIBUTOR

T

he future of farming was at the heart of discussions during the recent Nampo agricultural show, with a resounding emphasis on sustainability. Global energy company Shell led the discourse, reaffirming its commitment to advancing agriculture in South Africa.

The session, aptly titled “Farm of the Future,” convened industry experts and stakeholders to explore the transformative potential of renewable energy, emerging technologies, and strategic partnerships in shaping the agricultural landscape.

Reflecting on the event, Shell’s Country Chair for South Africa, Aluwani Museisi, emphasised the importance of continuous evolution. “Often, our adherence to past practices can blind us to the transformative possibilities of the future. We must maintain a relentless spirit of evolution. Shell is steadfast in its commitment to embarking on the journey towards the farm of tomorrow alongside our valued customers.

“Our commitment extends beyond mere rhetoric. We are actively investing in digital solutions that empower farmers to make data-driven decisions, optimise their operations, and ultimately contribute to a more sustainable agricultural sector.”

The key to this journey is collaboration, as highlighted

by Nazareth Tekeste, general manager of Shell South Africa

Lubricants. Tekeste stressed the necessity of end-to-end partnerships in addressing challenges. She emphasised Shell’s global and local initiatives to support farmers in equipment maintenance, citing partnerships with original equipment manufacturers (OEM) to provide after-market sales support.

“By not partnering from end to end to get things done, we are creating more challenges than solutions. Our collaboration with OEMs ensures that farmers have access to genuine parts and expert servicing, ultimately prolonging the lifespan of their equipment and reducing downtime. Additionally, our lubricants, equipped with temperature control and machinery maintenance features, offer tangible benefits in terms of efficiency and cost savings,” Teketse said.

Award-winning farmer and entrepreneur Mbali Nwoko echoed the sentiments on collaboration, underscoring the interconnectedness of agriculture with other industries.

“Through collaboration and innovation, we are not just farming; we are pioneering a revolution. Agriculture is the cornerstone of countless industries, and together, we are shaping a future where sustainability, technology, and prosperity converge.”

Nwoko highlighted the diverse facets of the future of farming, including innovations like vertical hydroponic farming, urban container farms, robotic farming, solar farms, self-driving automated tractors, automated livestock farms, and the integration of drones and sensors.

‘Emerging farmers to insure their operations’

L

and Bank Insurance Company is urging new era (emerging) farmers to understand and appreciate the importance of insuring their farming assets, as unforeseen events could have a catastrophic impact on their ability to continue farming.

Pascal Siphugu, Managing Director of Land Bank Insurance Company, has revealed that the low insurance coverage rate among emerging farmers is a significant concern for the organisation, as many of these farmers are potentially exposed to risks that can effectively shut down their farming operations.

“We strongly encourage emerging farmers to insure their assets, including livestock, crops, equipment, and buildings, in the event of an unfortunate and unforeseeable event. Without insurance coverage, these farmers could see their operations effectively wiped out, and it would be almost impossible for them to re-establish themselves in the sector,” he said.

Siphugu was speaking at an event organised by Land Bank at the annual Nampo Harvest Day. He noted that Land Bank Insurance Company has a strong social mandate to help with food security, rural crime, and curb unemployment in rural economies.

“Through our broker network, we are also keen to educate emerging farmers to treat their farming operations as business enterprises, and as such, there is a need to protect their assets and other risks through insurance to ensure business continuity,” said Siphugu.

“Our broker network is familiar with the risks and challenges specific to the various types of agriculture within the different regions of South Africa. These expert brokers will assess farmers’ specific risks and needs and advise them about the optimal insurance coverage their respective operations would benefit from.

“Insurance is often considered a grudge purchase until something happens. Emerging farmers must act responsibly and protect themselves against the multitude of risks that they face by getting the right insurance coverage,” he says.

Crop insurance provides farmers with financial security and protection on their investments. The product covers them in case of crop failure due to excessive hail, frost, wind and physical damage to the whole or part of their insured crop, which would otherwise mean a loss of income.

VEGETABLES & FRUIT | JULIE • AUGUSTUS 2024

5

NUUS NEWS

NEWS

SA to feed an additional four million people by 2030 According to PwC, South Africans buy less food as their spending power declines alongside elevated inflation. Precision agriculture, smart manufacturing, and retail planning can contribute to a greater domestic food supply, resulting in more affordable food.

I

n 2023, the volume of food and beverages sold per capita at South African grocery stores and supermarkets declined by 3,2%. It can be attributed to several factors, including the inflation-adjusted buying power of salaries and wages declining by 1,0%. Also, household spending was reprioritised as home loan repayments were at least 40% higher compared to three years ago due to higher interest rates.

Lullu Krugel, PwC South Africa Chief Economist, says South Africans are buying less food because of pressure on household finances.

“As a society, we need to make better use of our resources to ensure that food production is increased and that improved nutrition is available to more people at affordable prices. It requires agricultural players to produce more food crops sustainably, manufacturers to make food and beverage products more efficiently, and retailers and consumers to cause less loss and waste at the consumption level.”

PwC’s research has identified several levers that the broader food industry can pull to meet the current and expected future demand for nutrition sustainably and how to do so without significantly increasing food prices. These levers are: • Precision agriculture to increase farm production and sustainability; • smart manufacturing making better use of resources, and • reducing food waste at the retail and consumption level.

The assessment of the sector has also indicated that agricultural production will be different in the future. Farming will increasingly be supported by technology and big data, resulting in a farmer’s productivity increasing and their environmental footprint being reduced. By collecting real-time data on weather, soil and air quality, crop maturity, equipment and labour availability, predictive analytics can be used to make smarter farming decisions.

Precision farming tools support the improved utilisation and outcomes of agricultural assets, including: • a reduction in water use by, e.g., smart water management software and remote irrigation monitoring; • land management supported by, e.g., data collection, robotic planting and harvesting, and regenerative agriculture; • crop yields being boosted by, e.g., farm management software and predictive analytics, and • the well-being of livestock being improved by, e.g., remote health monitoring and automated feeding systems.

Demand planning is a process that involves forecasting and

6

VEGETABLES & FRUIT | JULY • AUGUST 2024

planning to meet future customer demand for products. It, in turn, informs their supply planning: how much raw materials should be ordered, how production should be scheduled, and how orders should be allocated across the supply network.

Weak demand forecasting accuracy can cause a surplus in food inputs if actual factory production is curtailed due to low sales, and a large surplus in food outputs if demand is less than what was anticipated when production was planned. At pre­sent, some 5,4 million tonnes of food is lost and wasted at the processing and packaging stage of the food supply chain due to these and other production challenges. This volume is around half of total food loss and waste across the value chain.

Manufacturers need to improve demand forecasting to take into account actual resource usage and client orders. Smart manufacturing uses demand-driven material requirements planning systems that improve traditional demand planning by being more responsive to real-time demand fluctuations.

“As one of the most unequal societies in the world, we need to make better use of our food resources,” says Vinesh Maharaj, PwC South Africa Smart Manufacturing leader.

“With half of food loss and waste occurring during the manufacturing process, it is imperative that food producers apply modern techniques to better plan their operations in order to minimise wastage. Modern technologies allow for better demand forecasts, production planning and input sourcing, thereby reducing surplus inputs and outputs at the factory level and the ultimate waste of food products.”

The South African food loss and waste initiative works with food manufacturers, distributors and retailers to halve the country’s food waste by 2030. Progress has already been made. South Africa’s food waste at the retail level declined from 15,8 kg per capita in 2019 to 15,4 kg in 2022.

Improving retail planning can reduce food waste at the retail and consumption level. There are several options, including: • upgrade demand planning systems: Implementing advanced inventory management technology can revolutionise how planners understand consumer demand trends. A better view of actual demand improves the deployment of stock across stores. This not only minimises waste but also streamlines operations.

• Modify store and marketing practices: Moving away from promotions like “buy one, get one free” can help prevent over-purchasing and subsequent waste at the consumption level. Elsewhere, advocating for more precise product labelling can assist consumers in making informed decisions. ­

uppe marketing A37985

Voldoen aan die se behoeftes

verbruiker

Dis nie net aartappels nie, dis ’n bydra tot gesonde gemeenskappe. Orvego® – BASF se innoverende swamdoder met Initium® bied hoogs effektiewe beheer van laatroes in ʼn IPB*-program.

Langdurige beskerming Reënvastheid selfs tydens vogtige toestande Gunstige toksikologiese en ekotoksikologiese profiel *Geïntegreerde plaagbestuur Kontak jou naaste BASFverteenwoordiger vandag nog.

BASF Suid-Afrika (Edms) Bpk • Sestiendestraat 852, Midrand, 1685 Posbus 2801, Halfweghuis, 1685 • Tel: +27 11 203 2400 Faks: +27 11 203 2461 • Webwerf: www.agro.basf.co.za Mobiele webwerf: m.agro.basf.co.za Orvego® Reg. Nr. L9185. Wet Nr. 36 van 1947. Aktiewe bestanddele: Initium® (Ametoctradin) 300 g/ℓ. Dimethomorph 225 g/ℓ. Waarskuwing.

Orvego® en Initium® is geregistreerde handelsmerke van BASF. Gevaarstellings: Skadelik indien ingesluk. Baie giftig vir akwatiese organismes met langdurige gevolge. Moenie eet, drink of rook wanneer die produk gebruik word nie.

Was gekontamineerde liggaamsdele deeglik na hantering.

LEES DIE ETIKET VOOR GEBRUIK.

NUUS NEWS

NEWS

Cases against EU citrus measures move forward at WTO South Africa has requested the establishment of two panels at a meeting of the dispute settlement body of the World Trade Organization to examine what, in South Africa’s view, are unscientific and discriminatory measures placed on citrus imported from South Africa by the European Union.

T

hese steps were taken to address the European Union’s (EU) regulations on two separate plant health issues: Citrus black spot (CBS) and false codling moth (FCM). The South African government is challenging the regulations to protect the livelihoods of tens of thousands of people in the local citrus industry. The SA government has the support of the Citrus Growers’ Association of Southern Africa (CGA).

South African citrus growers are grappling with a significant financial burden, spending billions of rands annually to comply with the CBS and FCM measures. These measures, which the industry deems unscientific and unnecessarily restrictive, are particularly challenging for emerging citrus growers. The urgency of resolving this dispute is underscored by the economic strain on the industry.

The South African citrus industry is currently entering its peak export season, with oranges heading to the ports. It is estimated that South Africa will export a total of 170 million 15 kg cartons this year. The exceptional quality of local citrus has made it sought-after internationally. South Africa is the world's second largest exporter of citrus.

South Africa's request to establish two panels underscores the gravity of the situation. This marks a significant development, as it is the first time South Africa has advanced a dispute at the World Trade Organization (WTO) beyond the panel state of the established dispute settlement body (DSB) process. The request is a clear indication of South Africa's determination to address the issue at hand.

On 15 April 2024, South Africa requested consultations with the EU on the CBS matter, which initiated a process that has ended without any results. On FCM, South Africa initiated consultations in July 2022 with no satisfactory conclusion. A panel will now also be formed on the FCM matter. While the EU did not at this time accept South Africa’s request for the two panels, the DSB procedure is that the requested adjudication panels will be established at its next meeting. A DSB panel report can usually be expected after nine months.

At the WTO headquarters in Geneva, the South African Government’s representatives reiterated the legal basis of their complaints. These arguments, which form the foundation of South Africa’s position in the dispute, include the following:

8

VEGETABLES & FRUIT | JULY • AUGUST 2024

• The measures are not based on scientific principles and are maintained without sufficient scientific evidence.

• The measures are applied in a manner that is not in accordance with the provisions of the Agreement on the Application of Sanitary and Phytosanitary Measures, of which the EU is a signatory.

• The EU fails to apply the measures in a uniform, impartial and reasonable manner.

• The measures are more trade-restrictive than required to achieve protection, and there are reasonably available alternatives that are technically and economically feasible and would achieve protection in a significantly less traderestrictive manner.

“Last year, we exported 36% of all our citrus to the EU,” said Justin Chadwick, CEO of the Citrus Growers Association (CGA). “That shows what an important market it is for our growers. It is the very foundation of citrus profitability in South Africa. Should the EU continue with the implementation of these measures or intensify them in any way, the profitability of hundreds of growers will be negatively affected, and the industry will suffer severe revenue and job losses.

“However, this is also potentially good news for European consumers. Their orange prices last summer were at an alltime high. However, if their supply is unfettered, consumers will benefit.”

“The citrus industry supports 140 000 jobs at farm level alone,” explained Mooketsa Ramasodi, Director-General of the Department of Agriculture Land Reform and Rural Development. “The government is acting to safeguard these livelihoods and the central role the citrus industry plays in so many of our rural communities.”

The Acting Director-General of the Department of Trade, Industry and Competition, Malebo Mabitje-Thompson, further clarified the government’s actions at the WTO: “The EU’s measures on CBS and FCM are not justified, proportionate or appropriate. It must be understood, however, that the WTO process is not confrontational or aggressive. The goal is scientific truth and fairness. We are making use of the WTO mechanisms available to us to find an amicable solution.” ­

NUUS NEWS

NUUS

Mozambican citrus growers join the CGA M

ozambique’s citrus industry has taken a significant step towards growth and sustainability by joining the Citrus Growers Association of Southern Africa (CGA). The CGA and the Mozambique Citrus Association (MCA) recently signed a memorandum of understanding. In joining the CGA, Mozambican farmers will now have access to a wealth of expertise and support.

Tertius Strauss, Mozambican citrus grower and General Manager of Verdant Produce Mozambique, is excited about the development.

“This is the start of what will turn out to be an incredible journey. This journey will continue for generations as we establish an enduring citrus industry in Mozambique. It is currently very small, about 350 hectares, but it has so much potential. Joining the CGA is one of the ways we are getting citrus in Mozambique up and running and onto the global stage.”

The CGA and its group of companies will empower the MCA in several ways. These include receiving technical assistance from Citrus Research International (CRI), advanced training by the Citrus Academy, and increased access to international markets through established CGA channels.

“Even though right now there are only two large citrus farms - one near Maputo and one near Massingir - it is not about the number of growers, but about the future possibilities. For instance, the orchards at Massingir are only three years old. It employs 150 people at the moment, but when the project is complete, it will provide over 800 jobs,” Strauss explains on behalf of the MCA. The MCA is a broad-based grouping of stakeholders engaged in the citrus industry. They are motivated to establish

New trees arrive in Mozambique.

a flourishing Mozambican citrus sector by leveraging their unique advantages, which include the nearby Port of Maputo.

Lemons, Valencia oranges and Grapefruit are currently grown in the south of the country.

“The CGA already represents over 1 560 growers from South Africa, Eswatini, Zimbabwe, Botswana and Namibia,” says Justin Chadwick, the CEO of the CGA. “It is a great pleasure to welcome our Mozambique neighbours as well. We are now a truly united Southern African industry association.

“The world appreciates the quality of citrus from our region. This represents immense opportunities for everyone in Southern Africa. By working together, growers across borders can achieve greater efficiency, competitiveness, and profitability.”

SA Star Ruby export forecast adjusted downward again

T

he Grapefruit Variety Focus Group announced on the 10th of June that a further downward revision to its export estimates for the 2024 season. Feedback from the regional grower representatives has corroborated the season’s trends seen in the packing and shipping data, necessitating a further adjustment to the predicted export figures.

• Red Grapefruit: Total exports projected at 11 430 600, 17 kg cartons. This is a 15% reduction from the initial estimate at the start of the season (13 475 600) and a 9% reduction from the revised total projected in May (12 572 030).

• White Grapefruit: Total exports projected at 512 810, 17 kg cartons. This is a slight 0,4% increase from the May projection but still represents an 8% reduction from the initial

estimate at the start of the season (557 460).

• PP Fruit: Total exports projected at 1 191 900, 17 kg cartons.

This is a 12% increase from the May projection and a 55% increase from the start of the season (767 080).

The 2024 season has proven to be unique in many respects. The most significant factors causing the revisions are smaller fruit sizes due to drier and warmer weather and good local processing prices.

Barry Landman, Chairman of the Grapefruit Variety Focus Group, said the Grapefruit season is approaching an early end.

Volumes are tapering off fast. The majority of all Grapefruit exports have been packed.

VEGETABLES & FRUIT | JULIE • AUGUSTUS 2024

9

DECIDUOUS FRUIT

Vergelegen shares lessons on combating grapevine leafroll disease in vineyards Vergelegen wine estate in Somerset West, a world leader in combating grapevine leafroll-associated virus 3 (GLRaV-3), the leading cause of leafroll disease, recently hosted an information session to share its lessons with wine producers and industry stakeholders.

L

eafroll disease is a major issue for winemakers globally. It decreases grapevine vigour and fruit quality, leading to lower yields. The virus affects grape colour, sugar content, and flavour, resulting in economic losses and high costs when vineyards must be replaced.

Twenty years ago, Vergelegen embarked on a programme to combat the virus, which is spread by insects called mealybugs. The estate now has the oldest white wine vineyards in the world, which are virtually virus-free.

In a Vergelegen population of several hundred thousand vines, it is thought that infected vines, which are promptly removed, are infected by mealybugs carried from a distance by wind.

Vergelegen viticulturist Rudolf Kriel said the programme was implemented in three phases: • planting new vineyards in former citrus orchards; • uprooting and replacing badly infected red wine cultivar vineyards; and • testing and treating white wine cultivars that, apart from Chardonnay and Semillon, do not readily show the effects of the virus.

Gerhard Pietersen, the lead researcher at Patho Solutions, has worked closely with Vergelegen since the project's inception.

He attributed “astounding results” to the estate's comprehensive approach and said that only 3% of South African wine

producers apply the programme as thoroughly. Smaller growers tend to replace vineyards “piecemeal”, mainly due to cost constraints and with little coordination between growers.

He gave an example of 30 wine producers in New Zealand – an entire appellation – who systematically replaced vineyards with new plantings. “It was remarkable how leafroll virus dropped in the whole area.”

In South Africa, the use of certified vine planting material that is confirmed as virus-free is voluntary. Californian authorities, on the other hand, are considering making virus-free material mandatory and may subsidise growers who replant vineyards.

As virus infection levels have been managed to extremely low levels at Vergelegen, the estate has now shifted to biological control of the mealybug vector. Kriel works with SkyBugs, a partnership between FieldBUGS, which supplies predatory Indigenous insects, and agritech company Aerobotics, which collaborates with a network of drone pilots to disperse the insects accurately over the vineyards.

The first stage is distributing predatory wasps, which are attracted by a pheromone released by female mealybugs. This proactive measure is followed by the distribution of ladybugs, which eat the mealybugs.

Viljoen said grapevine leafroll virus was “a huge challenge” in South Africa, but if replanted vineyards could be in production for 30 years instead of 20 years, producing better quality grapes that achieved higher prices, this was worthwhile.

Speakers at the Vergelegen leafroll information session were FieldBugs technical director Brahm Jonker, FieldBugs technical support specialist Ruan Erasmus, Vergelegen viticulturist Rudolf Kriel, Patho Solutions director Gert Pietersen, Patho Solutions lead researcher Gerhard Pietersen, Vergelegen laboratory technician Maritza van Rensburg, and viticulture consultant Francois Viljoen.

10 VEGETABLES & FRUIT | JULY • AUGUST 2024

PROMOSIE-ARTIKEL

DIE NAAM WAARVOOR JY MOET VRA

vir innoverende en volhoubare oplossings teen siektes in wingerd

As ’n erkende en innoverende markleier, fokus BASF daarop om langtermyn waarde en volhoubare oplossings aan produsente, die bedryf en die gemeenskap te bied. Wanneer dit by die beheer van swamsiektes in wingerde kom, bied BASF talle bewese oplossings teen donsskimmel, witroes (poeieragtige meeldou) en botritis.

DONSSKIMMEL Orvego®: Initium® en dimetomorf vorm saam ’n kragtige kombinasie wat ’n dubbele slag in die beheer van donsskimmel op wingerd toedien. Die voordeel van Orvego® se kort onthoudingsperiodes stel jou in staat om dit vroeg in die program toe te dien, terwyl die produk se uitstekende oplosbaarheid dit soveel makliker maak om te meng en toe te dien. Die chemiese klas waartoe Initium® behoort (FRAC Grp 45) maak Orvego® die ideale oplossing vir suksesvolle weerstand, sonder enige kruisweerstand. Verder maak die gunstige toksikologiese profiel van Orvego® teenoor die omgewing, gebruikers en verbruikers dit ’n ideale keuse vir geïntegreerde donsskimmelbeheer. Buitengewone reënvastheid binne een uur na toediening bied beskerming op die blare en trosse, selfs tydens nat toestande.

WITROES Collis® kombineer kresoxim-methyl en boscalid vir uitmuntende beheer teen witroes in ’n spuitprogram.

Die twee aktiewe bestanddele reageer verskillend op en binne die plantweefsel, wat bydra tot sistemiese voorkomende werking. Aangesien dit ook die gewenste nawerking bied, is Collis® ’n betroubare keuse wat goed in ’n afwisselende spuitprogram teen witroes pas.

Vivando® se enkele aktiewe bestanddeel, metrafenone, beweeg vinnig deur die kutikula tot in die onderliggende selle waar dit opbou en vandaar verder deur die blaarweefsel versprei. Vivando® is na toediening in ’n gasformaat rondom druiwetrosse teenwoordig, wat beskerming binne die tros bied. Dit is ook uiters reënvas en lewer goeie nawerking. Verder sorg die wye toedieningsvenster vir ’n wye keuse van posisionering in die witroesbeheerprogram, met geen kruisweerstand teenoor ander aktiewe bestanddele in die beheer van witroes nie.

BOTRITIS Cantus® WG is ’n water-oplosbare korrel met sistemiese werking, wat beskerming bied teen beide botritis en witroes. Cantus® WG se enkele aktiewe bestanddeel, boscalid, verhoed vroegtydige spoorontkieming en swamontwikkeling op en binne die plantweefsel. Dit word as enkelbespuiting voor trossluiting aanbeveel vir optimale beskerming teen botritis om uitstekende siektebeheer en buitengewone werking sonder die risiko van kruisweerstand te verseker. Die betroubare formulasie verseker uitstekende reënvastheid na toediening, en dus is geen hertoediening na reën of besproeiing nodig nie.

BASF Suid-Afrika (Edms) Bpk • Sestiendestraat 852, Midrand, 1685 • Posbus 2801, Halfweghuis, 1685 • Tel: +27 11 203 2400 • Faks: +27 11 203 2461 Webwerf: www.agro.basf.co.za • Mobiele webwerf: m.agro.basf.co.za Cantus® WG Reg. Nr. L7444. Wet Nr. 36 van 1947. Aktiewe bestanddeel: Boscalid 500 g/kg. • Collis® Reg. Nr. L7489. Wet Nr. 36 van 1947. Aktiewe bestanddele: Boscalid 200 g/ℓ. Kresoxim-methyl 100 g/ℓ. Waarskuwing. • Kumulus® WG Reg. Nr. L2404. Wet Nr. 36 van 1947. Aktiewe bestanddeel: Sulphur 800 g/kg. • Orvego® Reg. Nr. L9185. Wet Nr. 36 van 1947. Aktiewe bestanddele: Ametoctradin – Initium® 300 g/ℓ. Dimethomorph 225 g/ℓ. Waarskuwing. • Vivando® Reg. Nr. L8352. Wet Nr. 36 van 1947. Aktiewe bestanddeel: Metrafenone 500 g/ℓ.

Cantus® WG, Collis®, Initium®, Kumulus® WG, Orvego® en Vivando® is geregistreerde handelsmerke van BASF. Gevaarstellings: Cantus® WG en Vivando®: Giftig vir waterlewe, met langdurige gevolge. Indien mediese hulp benodig of aangevra word, maak seker u het die houer en etiket byderhand. Gooi enige oorblywende inhoud en houer weg by ’n versamelpunt vir gevaarlike afval. • Collis®: Moontlikheid dat dit kanker kan veroorsaak. Giftig vir waterlewe, met langdurige gevolge. Dra beskermende handskoene/klere/oogbeskerming. Indien blootgestel is of bekommerd is, soek mediese hulp. • Kumulus® WG: Indien mediese hulp benodig word, hou produkhouer of -etiket byderhand. • Orvego®: Skadelik, indien dit ingesluk word. Uiters giftig vir waterlewe, met langdurige gevolge. Moenie eet, drink of rook wanneer hierdie produk gebruik word nie. Was blootgestelde/besmette liggaamsdele deeglik na gebruik. LEES DIE ETIKET VOOR GEBRUIK.

uppe marketing A37420

Een van BASF se staatmakers, Kumulus® WG is ’n droëswael-swamdoder met goeie vermengingseienskappe. Die uiters betroubare formulasie met drie kenmerkende deeltjie-groottes wat optimum stabiliteit in suspensie het, dra by tot doeltreffende klewing en

nawerking in en op die blaar- en vrugoppervlak. Hierdie eienskappe verseker vinnige werking, volgehoue vrystelling en langdurige beskerming om witroes effektief te beheer.

DECIDUOUS FRUIT

Pieter du Toit awarded frontrunner award Pieter du Toit has been awarded the prestigious OSH Reinecke Frontrunner Award for 2024 by Hortgro, the industry association representing South Africa’s deciduous fruit growers.

D

u Toit is the third family member to receive this award, an accolade that honours industry leaders within the deciduous fruit industry who have excelled in leadership over an extended period.

“Pieter du Toit is widely regarded as a visionary and strategic thinker. Someone who can develop large businesses successfully and profitably. One of his strongest qualities is to apply his financial knowledge within a business environment,” says Anton Rabe, Hortgro’s Executive Director, who notes that the agricultural sector often fails to sufficiently acknowledge individuals who have dedicated significant time and service to the industry.

“With these longstanding prestigious awards, Hortgro seeks to recognise excellence and selfless service to the pome and stone fruit industries. The recipients of this year’s award categories contribute to an already impressive list of individuals who made their mark in agriculture,” he says.

In his career to date, Du Toit has played an essential role as a director across various agricultural entities, as well as within the deciduous fruit industry organisation. He was a board member of the South African Apple and Pear Producers Association (SAAPPA) for a decade, initially serving as vice-chairman and then as chairman between 1994 and 1996. He has also served on several boards, including Unifruco, Capespan, and a large commercial bank’s advisory committee.

“I am deeply grateful to accept this award, a recognition that truly belongs to the entire team at Dutoit. Every member and partner has played a crucial role in our

12 VEGETABLES & FRUIT | JULY • AUGUST 2024

shared success,” says du Toit. “As a leading farming, packing, marketing, and distribution enterprise, we recognise that our employees underpin the core of the business and that it is our social responsibility to empower and support the people in our communities. These values are rooted in our family heritage, with fourth and fifth-generation Dutoit family members actively contributing to our daily operations”.

Some milestones achieved under Du Toit’s leadership include the growth of Dutoit as a company that markets to 42 countries, the conversion in marketing from a one-channel system to a deregulated industry, the establishment of various cooling plants at Dutoit and other companies where he served as a director, and the associated modernisation of packaging plants under his leadership.

Over the years, Du Toit has remained intensely involved in industry operational functions, with his door always remaining open to those seeking his advice or assistance in resolving sensitive issues.

“As an industry leader, Pieter du Toit embodies the spirit of OSH Reinecke Frontrunner Award and is, therefore, a worthy recipient,” says Rabe.

This award, presented to an industry leader every year since 1972, motivates industry leaders to excel, set an example for other stakeholders and promote the interests of the deciduous fruit industry at a national and international level.

Pieter du Toit

Pome Fruit Portfolio Keep Growing

INSECTICIDES

Products to help you grow better pome fruit orchards. Corteva Agriscience™ offers a wide range of high-quality crop protection products to help you produce healthy, high-yielding and profitable pome fruits.

Delegate® 250 WG

Key Product Benefits

A water dispersible granule contact and stomach insecticide for the control of insects.

• Fast knockdown, short PHI • Favourable toxicological and environmental profile

Closer® 240 SC

Key Product Benefits

GF-120™ NF

Key Product Benefits

A selective concentrate bait for control of fruit fly species infesting various fruit and vegetable crops. Suitable for use in organic crop production.

• Active ingredient is of natural origin • Low risk to user, and low environmental impact

• Minimal impact on beneficial insects when applied A suspension concentrate systemic insecticide for according to recommendations the control of sap feeding insects.

• Useful in IPM programmes on a variety of crops

OUR CROP PROTECTION PRODUCTS ARE AT THE HEART OF AGRICULTURE FOR MORE INFORMATION CONTACT THE REGISTRATION HOLDER: Corteva Agriscience RSA (Pty) Ltd · Reg. No. 1997/003030/07 • Paarl +27 (0) 21 003 8259 • Centurion +27 (0) 12 683 5700 • 2nd Floor, Building A, Lakefield Office Park, 272 West Avenue, Centurion, 0157, Gauteng, Republic of South Africa.

ALWAYS USE ACCORDING TO LABEL RECOMMENDATIONS: • Closer® 240 SC contains Isoclast® (sulfoxaflor) (240 g/l) | Reg. No. L9694 | Act No. 36 of 1947 • Delegate® 250 WG contains JemvelvaTM (spinetoram) (250 g/kg) | Reg. No. L8392 | Act No. 36 of 1947 • Uphold® 360 SC contains Spinetoram/methoxyfenozide (360 g/L) • Reg. No. L10164 | Act No. 36 of 1947 • GF-120TM NF contains Qalcova® (spinosad) (0,24 g/L) • Reg. No. L7331 | Act No. 36 of 1947 TM ® Trademarks of Corteva Agriscience and its affiliated companies. © 2024 Corteva.

HAZARD STATEMENT(S) FOR CLOSER® 240 SC Very toxic to aquatic life with long lasting effects.

WARNING

HAZARD STATEMENT(S) FOR DELEGATE® 250 WG Very toxic to aquatic life with long lasting effects.

HAZARD STATEMENT(S) FOR GF-120™ NF

Harmful to aquatic life with long lasting effects.

Visit us at corteva.co.za

DECIDUOUS FRUIT

South African Bigbucks apple granted plant breeders’ rights in Australia Bigbucks, the improved Gala apple mutation from South Africa, known for its beautiful wine red colour, entered a new chapter after it was recently granted plant breeders’ rights in Australia.

“I

f anybody in Australia wants to plant a Gala-type apple, and they do not consider Bigbucks, they are shooting themselves in the foot. Bigbucks is now the improved Gala with the best colour potential,” explained Anthony Rawbone-Viljoen, on whose estate, Oak Valley, the mutation was discovered in 2011 in a Corder Gala orchard by Tru-Cape’s new variety specialist, Buks Nel. Since then, about 2,5 million trees have been planted in South Africa, with looming interest from America, India, and the European Union.

Together with Derek Corder, the founder of Corder Gala, Rawbone-Viljoen and Nel formed Pink Vein, a company aimed at promoting Bigbucks and the Flash Gala brand. Bigbucks apples that adhere to strict specifications are marketed under the Flash Gala banner, where the trademark has been registered in apple-consuming countries around the world.

“From our perspective, it is interesting that Australia is a market for domestically produced fruit, and the industry never fully focused on exports, so it is not a competitor to South African producers, making it a win-win situation,” Rawbone-Viljoen said.

After much deliberation, their paths crossed with Brendon Francis of Fruit Varieties International in Tasmania, and the long process of achieving plant breeders’ rights kicked off.

“Firstly, they had to get the plant material, plant it, and only then could authorities evaluate the fruit. The whole process took around five years,” explained Rawbone-Viljoen.

After a rigorous process of growing plant material and testing for viruses, Francis planted trees on different sites around Australia.

“Nurserymen were saying it stands head and shoulders above what they have in Australia. It is now over to them to promote the variety,” said Rawbone-Viljoen, who reckons Bigbucks will eventually be produced commercially in New South Wales, Western Australia, Tasmania, and Southern Australia.

“Bigbucks can colour better than any other Gala, so it is just a question of them making the variety known to local growers through the nursery industry.”

Eventually, specific nurseries will be granted planting licenses, which will be conditional upon meeting particular quality para­ meters.

14 VEGETABLES & FRUIT | JULY • AUGUST 2024

“We want growers to pursue the right way to do this by producing quality products matching the standard that we set for the variety from here.”

First-grade pack-outs Bigbucks is known to offer first-grade pack-outs of around 80% per bin. Some of the oldest orchards in South Africa are now about eight years old, and since full-bearing age, the best orchard has yielded over 150 tonnes per hectare, proving its potential as a winning option for growers.

Rawbone-Viljoen says it is absolutely extraordinary and changes the paradigm of the variety compared to other planting options.

The Gala category has a known track record and is well established globally, meaning the trade needs no convincing when it comes to varieties such as Bigbucks/Flash Gala.

“Gala is an established household name, and it is liked by consumers all over. An American marketing guy once said there are three important issues you need to consider when planting an apple. The first is red, the second is red, and the third is also red.

“Colour development in the blushed fruit category determines the pack-out, and the pack-out determines profitability.

The whole thing is pretty easy to understand if you end up planting top-end red varieties like Bigbucks.”

In terms of the agreement, Australians can use the Flash Gala brand name. Rawbone-Viljoen sees this as “potentially quite exciting”.

“Australia is a high-value market with the opportunity to charge prices that are interesting from a producer’s point of view.”

He admits that “when they pushed this boat into the bay” more than a decade ago, they didn’t fully know what they were getting into.

“I’ve been in the fruit business for a long time, but it required a specific science to take Bigbucks from a domestic variety to an increasingly global variety. At the end of the day, it is a competitive environment, and we have to make sure that we stay ahead of the game. It’s very exciting.”

Regalis® Plus Neem die plus en kry meer as wat jy verwag

Regalis® Plus is ’n:

 Groeireguleerder  Opbrengsbestuurder  Plantversterker

BASF Suid Afrika (Edms) Bpk • Sestiendestraat 852, Midrand, 1685 • Posbus 2801, Halfweghuis, 1685 • Tel: +27 11 203 2400 • Faks: +27 11 203 2461 • Webblad: www.agro.basf.co.za Mobiele webblad: m.agro.basf.co.za • Regalis® Plus Reg. Nr. L10535. Wet Nr. 36 van 1947. Aktiewe bestanddeel: Prohexadione-kalsium (acylcyclohexanediones) 100 g/kg. Waarskuwing.

LEES DIE ETIKET VOOR GEBRUIK. Gevaarstellings: Kan ’n allergiese velreaksie veroorsaak. Dra beskermde handskoene. Vermy inaseming van stof en dampe.

Regalis® Plus en AgCelence® is geregistreerde handelsmerke van BASF.

uppe marketing A37419

Het jy jouself die AgCelence®-voordeel gegee?

DECIDUOUS FRUIT

Keeping deciduous trees free from scheme viruses At the recent Hortgro Technical symposium, Gerhard Pietersen from Patho Solutions spoke to delegates about the importance of keeping deciduous trees free from scheme viruses.

P

ietersen founded Patho Solutions in 2016 and has established laboratories in Pretoria and Wellington that perform research, diagnostics and control of plant pathogens. Based in Wellington, the laboratories provide important services to producers in the Winelands and the deciduous fruit industry in the Western Cape.

Pietersen said that it is crucial to understand the epidemio­ logy to control a virus disease. Using the disease triangle can help producers determine weaknesses amongst the components interacting in the disease. The “scheme” viruses are apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple chlorotic spot virus (ACLSV), and apple mosaic virus (ApMV).

Some control strategies include vector control, resistant cultivars, the elimination/reduction of the virus’s sources, and modifying the environment.

Pietersen said that in vegetatively propagated crops - including stone and pome fruit - viruses in planting material play a significant role in the epidemiology of the diseases they cause.

Most, if not all, the progeny plants are infected by the virus.

Vegetative propagation of apples and pears is more than 150 years old. Propagation of pome and stone fruit is almost exclusively done by vegetative propagation in modern times.

Hugh Campbell, Hortgro technical and plant improvement manager, recently shared some of the most pertinent questions about plant improvement and its necessity for sustainable growth in an article on the Hortgro website, https://www. hortgro.co.za/news/plant-improvement-plantverbetering/.

Campbell said that plant improvement is a continuous process that aims to produce better fruit trees. New and improved genetics is one of the cornerstones of plant improvement. New cultivars provide better yields, colour, texture, and storability. Plants are also improved by removing economically important pests and diseases. A plant improvement scheme’s primary focus is to ensure plant material is free of economically important viruses.

There is no cure or spray for a virus or viroid. The only option is to remove and destroy a virus or viroid infected tree.

A virus is like a parasite. It does not kill the tree as it uses the cellular machinery of the tree to produce more viruses. The only way of managing viruses is to ensure that producers don’t have them in new trees before it is planted.

• Viruses are spread through propagation material – i.e., if budwood is cut from an infected tree, it will spread to all the trees made from that budwood.

• Viruses reduce the bud-take.

16 VEGETABLES & FRUIT | JULY • AUGUST 2024

• Economically important viruses can reduce tree growth and yield by 10% to 40%, depending on the virus.

• Viruses can reduce tree survival and increase management costs.

According to Campbell, the plant certification scheme is designed to provide planting material that has been tested to be clear of selected economically important viruses. Uncertified plant material requires that the trees be visually clean. A producer cannot easily see viruses on planting material. No virus tests are required for uncertified planting material.

Pietersen also reiterated that it is vital to have a “virus elimination step” - seed or other - or start with clean material, because if the producer has an accumulation of viruses in cultivated apples and pears it will also often result in mixed infections of multiple viruses.

Pietersen said that the irony is that because most pome fruit viruses lack a vector, and if producers control it by planting healthy plant material, it will eliminate these viruses from the industry - as done for apple rubbery wood disease in the UK. To ensure a producer has virus-free nuclear material of scions and rootstocks, virus-free material have to be selected or subject starting material to virus-elimination processes. There will be no need for further downstream tests if the grafted material is traceably derived from nuclear material.

Most countries with an active pome or stone fruit industry have certification schemes, e.g., Canada, USA, Australia, EU, Netherlands, France, Germany, UK, Italy, Spain, Hungary.

Campbell also added that in the context of plant improvement, certification is the process of providing growers with evidence that plant material of official varieties has been tested and certified for trueness to type (i.e. a Kakamas is a Kakamas), health status (free of scheme viruses etc.) and physical quality (size, thickness etc.).

The Deciduous Fruit Plant Improvement Association (DPA) is the delegated authority for plant improvement for stone and pome fruit in terms of the Plant Improvement Act 53 of 1976.

PlantSA is a non-profit company that manages the voluntary certification scheme for deciduous fruit (DPA) and grapevines (VIA). Only registered plant improvement organisations (PIO’s) may apply for the certification of propagation material.

The classic approach for plant improvement of “start clean – end clean” is to start with a nucleus plant that is placed in a bio-secure facility, tested clean, and kept clean through regular inspection and testing. Plant material from the nucleus plant is used to make foundation plants. These foundation plants are

DECIDUOUS FRUIT

used to provide material for mother plants, which are ideally placed in bud parks but are currently mostly in commercial orchards. The mother plants are inspected and regularly tested and are used to cut budwood that is provided to the registered nurseries to make nursery trees.

PlantSA oversees, inspects and audits this process throughout the year (spring, summer, autumn, and winter), providing a certified blue label for plant material that meets the scheme’s requirements.

The inspection of uncertified plant material is a function of the Department of Agriculture, Land Reform, and Rural Development (DALRRD). The DPA can refuse to certify trees, but only DALRRD has the power to prohibit the sale of non-

compliant trees. Currently, DALRRD has a capacity challenge and cannot fully meet this mandate.

Difference between the DPA and a PIO The DPA is the authorised authority that manages and inspects certified material. They, therefore, have an oversight role.

There are currently three PIO’s (SAPO, Topfruit and Stargrow) that operate under the DPA. The role of a PIO is to import, breed or select new or improved cultivars or clones. Currently, only PIOs may apply for certification of plant material. The PIOs are responsible for the multiplication of the certified plant material (buds) that they then provide to registered nurseries.

target destructive

mites and moths with dual action power

3 reasons to choose VOLIAM TARGO®: 1.

2.

3.

Double action: control codling moths and suppress red spider mites, to ensure top quality Pome production in your orchard All in one can: ensuring operator safety and easier application process IPM compatible: low impact on beneficial insects, ensuring sustainable production practices

VOLIAM TARGO®. The smart choice to ensure export quality apple and pear production in your orchard.

READ THE PRODUCT LABEL BEFORE USE. VOLIAM TARGO® (not restricted) contains abamectin (mectin) 18 g/ℓ and chℓorantraniℓiproℓe (ryanodine) 45 g/ℓ (Reg. No. L8545, Act 36 of 1947) WARNING. GHS-Hazard statements: Harmfuℓ if swaℓℓowed or inhaℓed. May cause damage to organs (nervous system) through proℓonged or repeated exposure. Very toxic to aquatic ℓife with ℓong-ℓasting effects.

VOLIAM TARGO®, the aℓℓiance frame, the purpose icon and the Syngenta wordmark are registered trademarks of a Syngenta Group Company.

Syngenta South Africa (Pty) Limited, Private Bag X60, Haℓfway House, 1685. Teℓ. (011) 541 4000. www.syngenta.co.za © Syngenta Ag, 2000. Copyright reserved. Aℓℓ unauthorised reproduction is forbidden.

@SyngentaSA | www.syngenta.co.za

17

PEPPERS

Resilient greenhouse varieties: A solution to powdery mildew in sweet pepper plants Powdery mildew is a common fungal disease that affects sweet pepper plants in greenhouse environments, posing a significant challenge to growers. In greenhouse agriculture, the battle against powdery mildew in sweet pepper plants has long been a challenge for growers.

ARNO RAUTENBACH PRODUCT SPECIALIST

T

he presence of powdery mildew can have detrimental effects on sweet pepper plants, leading to reduced photosynthetic activity, stunted growth, and decreased fruit quality and yield. Additionally, the aesthetic appeal of the fruits can be compromised, impacting marketability and economic returns for growers.

Effective management strategies include: 1. Cultural practices: Implementing proper spacing between plants to improve air circulation, reducing humidity levels, and maintaining optimal growing conditions can help minimise the risk of powdery mildew infestations.

2. Biological control: Introducing beneficial organisms such as predatory mites or fungi that antagonise powdery mildew can serve as an effective method of biological control within the greenhouse environment.

3. Chemical control: When necessary, the application of fungicides approved for greenhouse use can help manage powdery mildew. However, it is essential to rotate between differ-

Competition variety with limited powdery mildew resistance.

18 VEGETABLES & FRUIT | JULY • AUGUST 2024

ent fungicidal modes of action to prevent the development of resistance.

4. Monitoring and early detection: Regular scouting for early signs of powdery mildew and prompt intervention can prevent the disease from spreading and causing significant damage to sweet pepper plants.

5. The planting of powdery mildew resistant varieties.

In the realm of greenhouse agriculture, the battle against powdery mildew in sweet pepper plants has long been a challenge for growers. However, with Syngenta’s exceptional greenhouse varieties boasting robust powdery mildew resistance, a new era of disease management and crop protection has emerged.

Syngenta has developed a suite of greenhouse sweet pepper varieties renowned for their exceptional resistance to powdery mildew. These varieties, including Hokkaido, Masami, Sensei, and Kaamos, have been meticulously bred to thrive in greenhouse environments while exhibiting heightened resilience against the detrimental effects of powdery mildew infestations.

For more information, contact Syngenta South Africa offices, Tel: +27 (11) 541 4000 | www.syngenta.co.za .

Syngenta variety with powdery mildew resistance in the same greenhouse.

GENERAL

Physiological disorders in cucumbers under protection Cultivating cucumbers in greenhouses can offer several benefits to the producer, including longer growing seasons, protection from adverse weather and controlled growing conditions.

However, these protected environments can also lead to physiological disorders impacting cucumber yield and quality.

P

hysiological disorders can affect cucumber crops due to environmental and management factors. Temperature stress, improper moisture levels, and nutrient imbalances are common contributors to these issues. Proper management practices, including attentive watering, fertilisation and climate control, are essential to reduce the risk of physiological disorders and maintain the health and productivity of cucumber crops. Specific disorders include crooked fruit, thin necks, cold striping and fruit enlarged blossom-end.

maintain a minimum temperature of 15 °C, stabilise the relative humidity and implement a regular weekly foliar spray containing both boron and calcium.

Blossom end rot

Various factors, such as sudden changes in temperature and humidity, high levels of emulsifiable concentrate (EC), plant diseases, excessive fruit production, and stress from either inadequate water or high temperatures, can result in crooked fruit. This issue can significantly impact the quality of a crop, as signs may include stunted growth on one side of the fruit, leading to a bent appearance. Crooked fruit is not suitable for being sold in the market.

To address this problem, it is crucial to take steps such as maintaining consistent greenhouse temperatures, adjusting the application of fertilizers and irrigation, using foliar sprays containing calcium and boron, removing excessive fruit from plants and controlling thrips and diseases.

Blossom end rot (BER) is a physiological disorder characterised by the rotting and darkening of the blossom end of the fruit, particularly in tomatoes and peppers. BER is caused by a combination of factors, including high salinity, high concentrations of certain nutrients such as magnesium (Mg), ammonium (NH4+), or potassium (K), inadequate development of xylem tissue, rapid growth, imbalanced moisture levels, low levels of soluble calcium, and extreme temperature fluctuations.

It is important to consider a comprehensive approach that addresses these factors to prevent BER. This can include revising the fertigation (irrigation and fertilisation) programme to ensure a balanced nutrient supply, improving ventilation and transpiration to maintain optimal moisture levels in the plant and applying calcium supplements (particularly after periods of cloudy weather) to ensure adequate calcium availability for the developing fruit.

Maintaining consistent soil moisture, avoiding over-fertilization, and minimising fluctuations in environmental conditions can also reduce the risk of BER in plants.

Thin necks and cold striping

Potassium deficiency

Thin necks and cold striping can result from the thinning of the proximal end of the fruit and the formation of yellow and light green stripes between the ribs of the cucumber. To prevent the occurrence of thin necks in cucumbers, it is important to carefully select cucumber varieties that are well-suited to the prevailing environmental conditions. It is also essential to ensure that the temperature is consistently maintained at a minimum of 15 °C to discourage the development of thin necks.

To mitigate the occurrence of cold striping, it is crucial to

Potassium deficiency in plants can lead to issues like oversized blossom ends on fruits, stunted growth and symptoms such as chlorosis, bronzing, and leaf scorch between the veins. To address this, conduct a leaf analysis and adjust the fertilizer programme accordingly.

Physiological disorders such as crooked fruit, thin necks, cold stripes, and enlarged blossom ends pose significant challenges in greenhouse cucumber cultivation. These issues often result from environmental stress and nutrient imbalances and

Crooked fruit

20 VEGETABLES & FRUIT | JULY • AUGUST 2024

ALGEMEEN

Cold striping.

Crooked fruit.

can greatly impact the crop's marketability and yield. Growers can address these challenges by implementing targeted management strategies, including balanced fertilisation and consistent environmental control.

Proactive monitoring and timely interventions are essential for maintaining optimal growing conditions and achieving successful greenhouse cucumber production.

Thin necks.

DISCLAIMER: This information is based on Sakata’s observations and/or information from other sources. As crop performance depends on the interaction between the genetic potential of the seed, its physiological characteristics, and the environment, including management, Sakata gives no warranty express or implied, for the performance of crops relative to the information given nor do Sakata accepts any liability for any loss, direct or consequential, that may arise from whatsoever cause. Please read the Sakata Seed Southern Africa (Pty) Ltd. Conditions of Sale before ordering seed.

21

GENERAL

Plaagbeheer en risikobestuur Tradisioneel word die impak en waarskynlikheid van `n skade-voorval oorweeg om ’n strategie vir risikobestuur saam te stel. Om ’n sinvolle risikobestuurstrategie saam te stel, is dit gevolglik belangrik om te weet watter faktore om in ag te neem sodat ’n doeltreffende plaagbeheerplan ontwikkel kan word.

JACQUES FOUCHÉ NEXUS

S

o ’n strategie stel produsente in staat om ingeligte besluite te kan neem wanneer hulle bepaal of hulle die moontlike risiko’s wil bestuur, dit kan vermy of net moet aanvaar, gebaseer op die skade wat die betrokke plaag inhou, inaggenome die gewas se waarde.

Plaagdoders sluit swam- en Jacques Fouché insekdoders in en die primêre funksie is om die gewas teen die skade van plae soos swamme, aalwurms, myte en insekte te beskerm. Sekere plae het die vermoë om groot skade te veroorsaak terwyl ander minder skadelik is. Plae kan dus geklassifiseer word volgens die potensiële risiko wat elkeen inhou.

Net so kan ’n plaas verdeel word in areas met hoë en lae waarde. Die waarde van die area word deur faktore soos kultivarkeuse, aanvraag uit die mark vir die spesifieke kultivar, asook die kwaliteit van die gewas bepaal. ’n Kombinasie van ’n hoëwaarde-area en ’n hoërisiko-plaag hou die grootste finansiële risiko vir ’n produsent in.

Risiko’s kan oor tyd en areas wissel. Plae kan in sekere seisoene en sekere areas meer problematies wees, daarom is dit dikwels moeilik om akkuraat te voorspel hoe die risiko gaan uitspeel. Net so kan die waarde van die gewas oor seisoene en oor areas verskil. Dit is makliker om die gewas se waarde te voorspel as die plaag se skade.

Om gewasse optimaal te bestuur moet daar gemik word om die koste van die beheermaatreëls korrek toe te ken na gelang van die graad van die plaagskade. Alle spandering op beheermaatreëls moet lei tot verminderde finansiële verlies as gevolg van die plaagskade en die besparing in finansiële verlies moet ver die koste van die beheermaatreëls oorskrei. Ekonomiese skadevlakke, ekonomiese drempelwaardes en voorspellingsmodelle kan gebruik word om die gepaste beheermaatreël(s) te bepaal wat gebruik moet word in ooreenstemming met die graad van die plaag.

• Ekonomiese skadevlak is die vlak van plaagbesmetting waar die koste van die beheermaatreël(s) gelyk is aan die

22 VEGETABLES & FRUIT | JULY • AUGUST 2024

finansiële waarde van die skade wat aangerig word.

• Ekonomiese drempelwaarde is die punt in die ontwikke­ling van die plaagpopulasie waar beheermaatreëls gebruik moet word om te voorkom dat die plaagpopulasie die ekonomiese skadevlak bereik. ’n Ekonomiese drempelwaarde is dinamies en moet aangepas word soos die koste van die beheermaatreëls en die waarde van die gewas oor tyd wissel.

Drempelwaardes het verdere tekortkominge en word oor die algemeen slegs vir sekere plae gebruik en nie vir siektes nie.

As die risiko van die plaag akkuraat voorspel kan word, kan die gepaste beheermaatreëls se uitgawes ook akkuraat spandeer word.

Die grootste dryfkragte vir skadevoorspelling is: • klimaat, • geskiedkundige plaagvoorkoms, • plaageienskappe, • gewasvatbaarheid, • plaagmonitering en • beheermaatreëls se doeltreffendheid.

Klimaat is waarskynlik die grootste dryfkrag. Vir sommige siektes is reën nodig om te floreer. Indien reën en gepaardgaande blaarnatheid akkuraat voorspel word, sal dit moontlik wees om siekteinfeksie te voorspel. Hoewel die voorkoms van sekere siektes redelik suksesvol voorspel kan word, is dit meer uitdagend om die graad van die infeksie te voorspel.

Reën kan weer ander siektes soos poeieragtige meeldou verminder en programme kan aangepas word. Temperatuur is gewoonlik die dryfkrag vir plaagontwikkeling waar hoër tempera­ture (nie uitermatig nie) oor die algemeen tot vinniger insek­ontwikkeling lei en potensieel tot meer skade.

Die gewasbeskermingprogram moet aangepas word sodat uitgawes gepas toegeken word aan verskillende grade van risiko. Dit sal beteken dat ’n gewasbeskermingsprogram oor ’n area en oor tyd gaan verskil soos die risiko oor die area en tyd verskil.

Vir behoorlike beplanning en om ’n optimale beheerprogram saam te stel, is dit nodig dat inligting behoorlik en akkuraat ingesamel word.

Kontak ons gerus vir meer inligting oor risikobestuurstrategië by 021 860 8040.

OPTIMALE RISIKO-BESTUUR IS 'N BOUSTEEN VAN VOLHOUBARE PRODUKSIE Alle aksies in 'n boerdery moet sin maak. Dit geld ook vir risikobestuur en plaagbeheer.

Daarom is 'n behoorlike strategie nodig sodat jy die beste besluite kan neem vir jou boerdery.

DIE REGTE PLAN

DIE REGTE TYD

DIE REGTE PRODUK

Is jou produksie-inligting akkuraat genoeg om behoorlike produksiebeplanning en risikobestuur vir al jou gewasse te doen?

Om die beste plaagbeheerprogram vir jou boerdery saam te stel, is volledige en akkurate inligting die eerste stap op die pad na sukses.

Geskoei op dié inligting, kan bepaal word hoe moontlike risiko's bestuur of vermy kan word.

NexusAG Croplife-geakkrediteerde gewasadviseurs kan jou help om die risiko’s op jou plaas volhoubaar te bestuur met maatpas bestuursprogramme wat elke produsent se unieke omgewing en spesifieke omstandighede in ag neem.

KONTAK ONS VIR MEER INLIGTING: www.nexusag.net 021 860 8040

GENERAL

Vyeroes onder die soeklig Met navorsing oor roes op vyebome is onder meer bevind dat ‘n gewilde immergroen rankplant in tuine moontlik ‘n rol speel as die bron van besmetting. Ander faktore soos die vyeboom se besmette blare van die vorige seisoen, omgewingstoestande en kultivareienskappe kan egter ook ‘n rol in besmetting speel.

WILLEM BOSHOFF, BOTMA VISSER, ZAKKIE PRETORIUS DEPARTEMENT PLANTWETENSKAPPE, UNIVERSITEIT VAN DIE VRYSTAAT

V

yeroes, veroorsaak deur die swam Cerotelium fici, is in 1927 vir die eerste keer op blare van die eetbare vy (Ficus carica) in Suid-Afrika aangeteken. Die eerste tekens van die siekte is sigbaar as vlekke op die blaar se bokant, gevolg deur ligbruin tot bruin roespuisies op die onderste oppervlak, namate die swam in die blaar groei en ‘n volgende generasie spore produseer.

Die puisies het ‘n poeieragtige voorkoms en huisves die swamspore wat herversprei en nuwe infeksies kan veroorsaak.

Die vlekke bo-op die blaar vertoon later bruin met ‘n hoekige voorkoms, smelt saam en lei uiteindelik tot gedeeltelike of algehele afsterwing van die blaar.

Tydens hewige infeksies op vatbare kultivars kan die hele blaarskyf aangetas word, maar roes is gewoonlik beperk tot areas waar vog opbou, byvoorbeeld tussen prominente blaar­ are.

Na aanleiding van onlangse gevalle van roes op vyebome in huistuine, kommersiële aanplantings en kwekerye is ‘n projek geloods om meer oor die siekte uit te vind. In teenstelling met historiese rekords is die veroorsakende swam, versamel vanaf verskeie gebiede in die Wes-Kaap en in Bloemfontein, met behulp van DNS-ontleding as Phakopsora nishidana geïdentifiseer.

Cerotelium fici en Phakopsora nishidana is morfologies baie eenders en kan nie tans sonder DNS-toetse onderskei word nie.

Infeksiestudies onder gekontroleerde toestande met 15 vykultivars het beduidende verskille in gevoeligheid vir roes

24 VEGETABLES & FRUIT | JULY • AUGUST 2024

aangetoon. Die kultivars Noire de Caromb, Cape White en Tiger was die vatbaarste. Geen tipiese roessimptome is op vrugte waargeneem nie, hetsy in die veld of tydens die infeksiestudies. Moerbei en treurmoerbei, wat aan die dieselfde plantfamilie as die eetbare vy behoort en in ander wêrelddele as gashere vir Cerotelium fici aangemeld is, was bestand teen Phakopsora nishidana.

In ‘n interessante verwikkeling is heelwat roes op kwekeryplante van Ficus pumila, ‘n gewilde immergroen rankplant in tuine en bekend as “tickey creeper” in Suid-Afrika, waargeneem. Hierdie swam is ook bevestig as Phakopsora nishidana en speel dus heel moontlik ‘n rol as ‘n infeksiebron vir bome van die eetbare vy. Tot dusver kon geen ander Ficus-spesie as ‘n gasheer vir die swam bevestig word nie.

Hoewel die oorlewing van die swam nog nie in Suid-Afrika bestudeer is nie, blyk dit dat droë, besmette blare van die vorige seisoen, bome wat in beskutte gebiede groei en nie noodwendig alle blare aan die begin van die winter afgooi nie, en ander spesies soos die rankplant, bydra tot inokulum vir infeksies in ‘n nuwe seisoen.

Dit is belangrik om daarop te let dat vyeroes seisoenaal is en dus nie elke jaar sal voorkom nie. Roes is ook meer algemeen in vogtige produksiegebiede in teenstelling met droër areas waar gewoonlik min of geen probleme met die siekte ondervind word nie. Faktore soos kultivarvatbaarheid, inokulumbronne, matige temperature, vog in die groeiseisoen, windverspreiding van die swamspore en tyd van aanvang van infeksie gedurende die seisoen dra alles by tot die voorkoms en infeksievlakke van vyeroes.

Navorsing wat elders gedoen is dui daarop dat die spore ontkiem binne 6 ure van konstante blaarnatheid met ‘n tem-

1

ALGEMEEN Roessimptome aan die onderkant (1-2) en bokant (3) van blare van die eetbare vy (Ficus carica) en op die rankplant Ficus pumila (4). Spore van die swam Phakopsora nishidana wat roes op beide hierdie Ficus-spesies veroorsaak word in (5) aangetoon.

3

2

4 5

peratuurvenster van 18 °C – 28 °C. Indien hierdie toestande vir 14 uur voortduur is infeksie, wat plaasvind deur die huid­ mondjies aan die blaar se onderkant, gewoonlik suksesvol.

Tipiese simptome kan onder gunstige toestande vir siekteontwikkeling binne 12-14 dae na infeksie waargeneem word.

Tydens seisoene waarin roes epidemiese afmetings aanneem kan die bome ontblaar word. Die presiese uitwerking wat dit op die groeikragtigheid van bome en produksie het is ook nie in Suid-Afrika bekend nie, aangesien sulke toestande gewoonlik aan die einde van die groeiseisoen voorkom.

Ten spyte van die feit dat vye op relatief klein skaal in SuidAfrika verbou word, sal beter gekoördineerde navorsing oor die beheer van swamsiektes tot produsente se voordeel wees.

Verdere haakplekke is die gebrek aan ‘n wyer keuse van gere­ gi­­streerde middels met bewese doeltreffendheid teen roes­ swamme, asook internasionale beperkings op die neerslag van landbouchemiese middels op vars vye wat uitgevoer word.

Vir meer inligting kan die volledige artikels oor roes op vye en die “tickey creeper” geraadpleeg word deur die ska­ kels https://doi.org/10.36253/phyto-13034 en https://doi. org/10.1094/PDIS-12-23-2794-PDN te volg of ‘n navraag per e-pos te rig aan Willem Boshoff by Boshoffwhp@ufs.ac.za.

25

advancing beyond the basics seeds | science| service

Donatello* • • • • •

Excellent cherry plum combined with high yield potential Strong plant withvery early maturity Suitable for single fruit or cluster picking Firm fruit offer extended shelf life Average fruit size of 22 - 24g

Torcida* • • • •

Vigorous plant with good disease resistance Firm fruit with great taste and long shelf life Average fruit size of 180 - 200g Very well suited for undercover production

| www.nuvance.co.za | For full terms and conditions, please visit www.nuvance.co.za * pending variety listing

SV 2444 TH* • • • • •

Early indeterminate round variety Good set and high production potential Average fruit size of 140 - 160g Very well suited for open field production Able to grow across regions with different climatic conditions

Rouja* • • • •

Early indeterminate round variety Good set and high production potential Average fruit size of 170 - 200g Very well suited for open field production

GENERAL

Crop4Life enhances the uptake of calcium in oranges and mandarins The South African citrus industry is the second largest exporter of citrus fruit globally, following Spain, with more than 100 000 ha under citrus production. Over the past two decades, the industry has grown at a fast pace, and the citrus area that was planted quadrupled between 2001 and 2020.

Dr Nico Hanekom, Dr Ida Wilson and Dr Onai Mtengwa, BIOREVOLUTION

T

he significant growth in the citrus industry is built on high-quality fruit production and adherence to the standards and requirements of export markets. Oranges, soft citrus, lemons, grapefruit, and limes are produced, while oranges and mandarins make up the main component of the fruit that is exported.

• It is integral for cell wall development and structure, imparting strength and integrity to plant tissues.

• Regulates numerous plant physiological processes, inclu­ding enzyme activation, membrane permeability, and nutrient uptake mechanisms.

• Facilitates transport and distribution of nutrients, fostering growth, and development of tissues.

• Serves as a bridge between pectin molecules and improves the integrity of cell membranes through bonds with phospholipids.

• Bolsters tree vigour and maximises tree productivity.

Oranges and mandarins Globally, South Africa is amongst the top ten producers of oranges and mandarins. The industry is strongly oriented to export, and almost 80% of fruit produced is exported, with the remainder consumed locally or processed for juice.

To meet export standards, the fruit’s rind must be free of blemishes and scars, and fruit quality must adhere to specific standards, including the desired colour, sweetness, and absence of biotic or abiotic lesions. Several wound-infecting rot fungi cause major losses in this industry. If fruit rinds are thin, injuries and wounds in rinds are more difficult to manage.

Calcium is needed for healthy trees Calcium is a macronutrient required in high quantities for both the structural and physiological functions of plants. Calcium plays a pivotal role in plant health.

Exogenous applications of calcium to citrus trees have proven to support the production of high-quality citrus fruit since calcium:

26 VEGETABLES & FRUIT | JULY • AUGUST 2024

Calcium also participates in stress signalling as a secondary messenger. During an immune response, extracellular signals such as cytokines or antigens bind to receptors on immune cells, triggering a signalling cascade. Calcium ions are released from intracellular stores or enter the cell through calcium channels in response to these signals. The increase in intracellular calcium concentration signals to activate downstream immune signalling pathways.

Signs of calcium deficiency in trees In citrus trees, calcium deficiency manifests deterioration in chlorophyll concentration along the leaf perimeters and interveinal regions, predominantly during winter months. In time, leaves will become necrotic, or leaves may also develop as diminutive, thickened leaves.

Overall, trees with calcium deficiency may decline in vitality, which is noticeable in the sparseness of foliage and lower overall fruit yield. Severe deficiency can result in twig dieback.

ALGEMEEN Table 1. Trial number and areas for trials done on Navel oranges and mandarins in South Africa

Trial number

Citrus type

1

Navel orange

Area on map

Cultivar

Farm close to

Province

Experimental trials 2

Palmer

Piekanierskloof

Western Cape

2

Navel orange

1

Palmer

Kirkwood

Eastern Cape

3

Navel orange

1

Palmer

Kirkwood

Eastern Cape

4

Navel orange

1

McClean

Kirkwood

Eastern Cape

5

Navel orange

1

McClean

Kirkwood

Eastern Cape

6

Navel orange

1

McClean

Kirkwood

Eastern Cape

7

Mandarin

1

Nova

Kirkwood

Eastern Cape

8

Mandarin

2

Nules

Piekanierskloof

Western Cape

Commercial trial 9

Navel orange

3

Delta

Musina

Calcium is needed for citrus fruit integrity Calcium is a major contributor to high fruit quality. Calcium levels impact: • The physiological development of fruit.

• Quality maintenance of fruit by upholding cell wall integrity, which in turn serves as a protective shield against rind disorders and mitigates fruit susceptibility to physiological abnormalities.

• Elevates overall fruit quality.

Calcium directly regulates the development and ripening of fruit. It maintains cell wall structure, which in turn supports fruit firmness and delays the ripening and softening of fruit by inhibiting cell wall degradation and delaying fruit senescence.

Calcium also affects hormone signalling, which plays a role in the regulation of fruit sets and cell division. Lastly, calcium is known to be a messenger molecule in plants that plays a role in the processes that support adaptation to the environment and stress responses.

Signs of calcium deficiency in fruit When fruits lack an adequate amount of calcium, fruit firmness decreases, and fruit experiences increased susceptibility to diseases, a shorter shelf life, and potential loss of nutritional value.

In the orchard, citrus trees experiencing calcium deficiency yield fruit that are stunted and irregularly shaped, with desiccated juice vesicles. The juice content of fruit from calciumdeficient trees is slightly lower and exhibits elevated levels of soluble solids and acids.

A calcium deficiency in fruit causes fruit loss and cracking of peel directly impacting the fruit’s market value for the producer. Calcium deficiency in citrus also leads to thinner rinds, poor fruit development and smaller fruit size. Proper calcium management through soil amendments or foliar sprays is essential for optimal citrus fruit size and quality.

More about calcium deficiency Calcium deficiencies are more prevalent in acidic soils where native calcium has been leached away. The continuous application of ammonium-based fertilisers, particularly ammonium sulphate, may exacerbate calcium depletion from soils. Simi-

VEGETABLES & FRUIT | JUL • AUG 2024

27

Limpopo

Figure 1. The trial work was conducted in three different citrus production areas in South Africa over several years.

larly, the use of muriate of potash and sulphur contributes to calcium loss. Soil liming not only ameliorates soil acidity but also provides accessible calcium.

Additionally, highly saline soils with elevated sodium concentrations can induce calcium deficiency, a condition that can be remedied by gypsum application to mitigate sodium’s adverse effects. Foliar spraying with a water-soluble calcium source is very effective in correcting calcium deficiency in citrus trees.

In South Africa, citrus cultivation encounters notable hurdles, predominantly characterised by rind disorders that impact fruit quality, thickness, size, susceptibility to post-harvest

TO PAGE 28

UNLEASH

THE GREEN

REVOLUTION !

Energy management using Innovative Technology.

World Focus Agri, a South African leader in Soil Remediation, Organic Chelated Leaf Nutrition, and Plant Energy Management.

Over the past thirteen years we’ve been serving small-scale and commercial farmers, building a strong market presence in South Africa, Namibia, Zambia, Mozambique, Botswana, and Malawi.

Product range Products developed for a wide range of flowers, plants, crops, all grain, deciduous fruit, apples, citrus, vegetables, sugarcane etc.

www.worldfocusagri.co.za

The World Focus Agri product range consists out of the following Soil Remediations;

Complex-range

Ultrafine Lime and Gypsum for easy application and rapid soil and plant availability. Packaging: 25kg, 1kg, 500g, 100g Foliar feeds.

Glio-range

Enhances growth and yield for all African produced crops, with specific products for different growth stages. Packaging: 5L, 1L, 500ml, 250ml.

Contact us

076 272 9512 l 082 452 8983 at@worldfocusagri.co.za Address: 9 Silver Crescent, Delmas, 2210

GENERAL

Crop4Life enhances the uptake of calcium in oranges and mandarins FROM PAGE 27 Table 2. Treatments, dosage, and application timings of C4L sprayed on Navel oranges

Dosage/ha in circa 1500 L water /ha

Treatments Crop4Life (C4L)

500 ml

Untreated control

none

100% Petal drop

Fruit set

Cell division and fruit growth

none

none

none

Table 3. The difference in calcium content of fruit from trees treated with C4L when compared to fruit from trees that did not receive C4L

Calcium

Type

Navel orange

Mandarin

Cultivar

Treated (mg/100 g)

Control (mg/100 g)

Difference treated-control (mg/100 g)

Percentage difference (%)

Delta

55

41

14

34

Palmer

58

36

21

59

Palmer

37

24

12

51

Palmer

42

30

12

39

McClean

23

31

-8

-27

McClean

37

24

13

53

McClean

38

31

7

23

Average

41

31

10

33

Nova

24

14

10

73

Nules

32

28

4

15

Average

28

21

7

44

decay, and physiological attributes. These challenges are closely associated with calcium deficiencies.

Crop4Life (C4L) is an environmentally friendly plant extractbased biostimulant that promotes plant health. It is not harmful to soil microbes, insects, other animals, or humans. It has undergone decades of rigorous research and development in the laboratory and the orchard. C4L is currently registered in South Africa for use on 48 crops for a wide variety of benefits to plants, including increasing the overall health of plants and maintaining quality in fresh produce, and post-harvest.

The investigations aimed to determine if the application of C4L at three intervals during the growing season would have an impact on the calcium content of fruit. Since the calcium content of fruit is directly and indirectly associated with plant health and high-quality fruit, the application of this product could provide a method for farmers to ensure that calcium applied to trees is successfully taken up by the plants and translocated to the fruit.

MATERIALS AND METHODS Trials Eight trials were historically done over three different geographical regions in South Africa (Table 1). Three Navel orange trials were done in the Eastern Cape and one in the Western Cape. Additionally, one Mandarin trial was done in the Eastern Cape and one in the Western Cape (Figure 1).

Experimental trials For the eight experimental trials, trial plots were demarcated

28 VEGETABLES & FRUIT | JULY • AUGUST 2024

within commercial orchards. For each treatment, four replicate trees received three applications of C4L in October, November, and December when the trees reached the respective phenological stages of 100% petal drop, fruit set cell division and fruit growth (Table 2). These phenological stages are about 28 days apart, but they will differ according to the type of citrus, the climate of the region and the specific cultivar.

Treatment applications were made as an additional spray to the farmers’ standard spraying programmes (nutritional, crop protection and others), while the untreated control represented the farmers’ standard spray programme. Treatments were applied with a motorised knapsack sprayer to the point of runoff.

Commercial trial Additionally, the effect of the application of the product was tested in the commercial environment on Delta Valencia oranges in the following season. The product was also applied at 100% petal fall, at fruit set, and during the early growth and cell division of fruit, roughly during October, November, and December growth (Table 2) on 5 hectares of orchards.

Assessments At harvest, 20 fruits were collected from different canopy positions in the treated trees as well as in the control trees to gather representative samples respectively. The samples were sent to the Accredited Agricultural Laboratory Bemlab in Strand in the Western Cape. A nutrient analysis was done for nitrogen, phosphorus, potassium, calcium, magnesium, sodium, man-

TO PAGE 30

Breëspektrum Insekbeheer vir Groeikragtige Gewasse

Circaden

®

Insekbeheer aangedryf deur

Nuwe generasie CIRCADEN ® 200 SC insekbeheer van FMC bied breëspektrum beheer in gewasse teen skadelike insekte waaronder belangrike spesies witvlieg, plantluise, blaaspootjies, bladmyners en Lepidoptera.

CIRCADEN ® 200 SC verbeter gewasvestiging in gewasse soos tamaties, soetrissies en kool deur vroeë seisoen grondtoediening tydens plant of oorplant (saailinglaai deurdrenk of drupbesproeiing). Langwerkende CIRCADEN® 200 SC lewer ‘n unieke aksie wat insekgedrag beïnvloed deur spierfunksie te benadeel. Insekte hou vinnig op om te voed, wat uitstekende plantbeskerming tot gevolg het. Boonop het CIRCADEN® 200 SC ‘n gunstige omgewingsprofiel en is ideaal vir IPM-programme. Verhoog die groeikragtigheid van jou groente- en vrugtegewasse vir sterker, gesonder plante, beter gehalte en groter opbrengste.

Kontak jou naaste FMC-areabestuurder om meer uit te vind oor die talle voordele van CIRCADEN® 200 SC insekbeheer.

CIRCADEN® 200 SC Reg. Nr. L11488, Wet Nr. 36 van 1947, bevat siantraniliprool (antraniliese diamied) – 200 g/L (Cyazypyr), waarskuwing, skadelik indien ingeasem, baie giftig vir waterlewe met langdurige effekte.

FMC Chemicals (Edms) Bpk, Posbus 44, Postnet Menlyn, Waterkloof Glen, 0181, Republiek van Suid-Afrika. CIRCADEN® 200 SC en Cyazypyr® is handelsmerke van FMC Corporation of sy affiliate.

www.ag.fmc.com/za/en

GEBRUIK PLANTBESKERMINGSPRODUKTE MET VEILIGHEID EN VERANTWOORDELIKE SORG. VOLG AANWYSINGS OP ETIKET TEN ALLE TYE MET TOEDIENING VAN PLANTBESKERMINGSPRODUKTE.

TD 24/024

TD 20/076R

GENERAL

Crop4Life enhances the uptake of calcium in oranges and mandarins FROM PAGE 28 ganese, iron, copper, zinc, and boron. Macro elements N, P, K and Ca were measured in mg per 100 g fresh mass and micronutrients Na, Mn, Fe, Cu, Zn and B were measured in mg/ kg (parts per million). For the sake of clarity and brevity, only results for calcium will be presented in this report.

bilising membranes, modulating water relationships, and activating stress signalling pathways. Moreover, fruit from trees where calcium is sufficient tends to be bigger than in those where calcium deficiency is experienced.

Results

Although numerous methods for calcium delivery to plants are known, such as applying fertiliser lime, and foliar calcium sprays, the direct evidence that the calcium is absorbed and provides the intended benefits is not well documented. Given that many factors interplay with the availability of calcium including fertiliser source, fertiliser placement, soil type, and crop cultivar, it is not always easy to know how well calcium is absorbed and translocated.

Crop4Life is scientifically proven to promote root growth and activity, improving soil structure and nutrient availability.

Potentially it is these processes that influence calcium absorption and transport within the citrus trees. The results of the reported studies conclude that C4L application as recommended on the label should enhance the uptake of calcium in citrus, and subsequently impart numerous benefits to the quality of the fruit as well as the longevity of fruit after harvest.

Conclusion The application of C4L to citrus trees enhanced the uptake of calcium in fruit in eight of the nine (89%) trials in which the potential uptake of citrus was evaluated (Table 3). Only for one instance of the McClean Navels was a decrease in calcium content observed. The reason for this anomaly is not clear. On average, a 33% increase in calcium content in fruit was measured for oranges and a 44% increase for mandarins.

Considering the multiple ways in which calcium impacts fruit quality, the following benefits may be gained from higher calcium content in citrus.

Tree health Calcium is a crucial signalling molecule that triggers and coordinates various stress response pathways in plants, ultimately enhancing their ability to tolerate and adapt to different abiotic and biotic stresses. It is closely associated with the immune response in trees. When immune cells encounter pathogens or foreign substances, they need to communicate and coordinate their activities.

Calcium ions help facilitate this communication by acting as secondary messengers. Calcium ions also regulate membrane cell function, cell activation and cytokine production. It also imparts structural fortification in cell walls, supporting plant tissues to withstand diverse environmental stresses and fend off disease pressures effectively.

Benefits to fruit Maintains physiological quality The adequate uptake and presence of calcium in fruit assists overall fruit health. It results in robust rinds, and the presence of calcium further mediates membrane functions and processes that regulate fruit quality. Factors like fruit ripening and senescence, firmness and shelf-life are modulated. Primarily, the uptake of calcium in fruit means the fruit will maintain hardiness, thus, it reduces physiological decline, which improves fruit quality.

Supports longer post-harvest longevity and disease resistance Scientific studies show that increased calcium content in plant storage organs enhances natural resistance to postharvest diseases. During fruit senescence, the soluble calcium in the fruit decreases, leading to the degradation of the fruit cell walls, giving access to fruit decaying fungi and causing deterioration of fruit.

Calcium furthermore helps prevent decay in fruits by sta-

30 VEGETABLES & FRUIT | JULY • AUGUST 2024

Reading list Anonymous, 2022. South African fruit trade flow. Trade Unit of the Markets and Economic Research Centre Issue No. 48. https://www.namc.co.za/wp-content/uploads/2023/02/SA-FruitFlow-Report-Issue-48-December-2022_Final.pdf Chisoro, S. and Roberts, S., 2024. Grower Power for Value Creation in High-Value Horticulture? The Case of Citrus in South Africa. The European Journal of Development Research, 36(1), pp.1-24.

Conway, W.S., Sams, C.E. and Kelman, A., 1994. Enhancing the natural resistance of plant tissues to postharvest diseases through calcium applications. HortScience, 29(7), pp.751-754.

Fischer, G., Balaguera-López, H.E. and Álvarez-Herrera, J., 2021.

Causes of fruit cracking in the era of climate change. A review.

Agronomía Colombiana, 39(2), pp.196-207.

Gao, Q., Xiong, T., Li, X., Chen, W. and Zhu, X., 2019. Calcium and calcium sensors in fruit development and ripening. Scientia Horticulturae, 253, pp.412-421.

Ghosh, S., Bheri, M., Bisht, D. and Pandey, G.K., 2022. Calcium signalling and transport machinery: Potential for development of stress tolerance in plants. Current Plant Biology, 29, p.100235.

Hashimoto, K. and Kudla, J., 2011. Calcium decoding mechanisms in plants. Biochimie, 93(12), pp.2054-2059 Seybold, H., Trempel, F., Ranf, S., Scheel, D., Romeis, T. and Lee, J., 2014. Ca2+ signalling in plant immune response: from pattern recognition receptors to Ca2+ decoding mechanisms. New Phytologist, 204(4), pp.782-790.

Xiong, T., Tan, Q., Li, S., Mazars, C., Galaud, J.P. and Zhu, X., 2021. Interactions between calcium and ABA signalling pathways in the regulation of fruit ripening. Journal of plant physiology, 256, p.153309.

Ontgin die landboumark ten volle...

Maak gebruik van die spesialiste UITGEWERS VAN: Koringfokus / Wheat Focus: Die spesialistydskrif vir kleingraan in Suid-Afrika Vegetables & Fruit / Groente & Vrugte: Ontgin alternatiewe moontlikhede in nismarkte Subtrop Journal: Joernaal vir avokado-, mango- en lietsjiekwekers.

Navorsingsjoernaal: SA Avokadokwekersvereniging (SAAGA) SA Lietsjiekwekersvereniging (SALGA)

NORTH WEST: POTCHEFSTROOM

GAUTENG: NORTHCLIFF

GAUTENG: PRETORIA

www.mediacomcc.co.za

 018 293 0622 info@mediakom.co.za

 011 476 3702 mediacom@lantic.net

 082 927 8294 vegandfruit@mediakom.co.za

Clarkstraat 17, Potchefstroom, 2531

Using modern technology to simplify and enhance the fruit exportation process

Evolve your business and become a global competitor.

First Technology is bridging the gap between one of the

to automating governance and

oldest industries in the world and the endless wonders of

compliance procedures, our solutions

modern and emerging technology. Through infrastructure

will liberate your workforce from

transformation and a seamless digital ecosystem of

menial responsibilities, significantly

traditional and cloud-based offerings, our holistic range of

cut down operational costs and

industry-leading solutions offers tremendous flexibility and

provide your business with the ability

can be scaled to address the needs of both SMMEs and

to quickly adapt to market demands

Large Enterprises.

and needs.

From warehouse modernisation and streamlining the exportation process,

Get in touch with Mandy McEvoy at mandym@firsttechnology.co.za or call us directly on 021 525 7000.

Blog