Flowers and Vegetables –Rising to the costs of greenhouse production DAY 1
Greenhouse Canada presents the latest in research, technology and production practices for flower and vegetable growers. Invited speakers will highlight new trends, tackle issues from a local perspective, and promote discussion among growers and suppliers. It’s about advancing the industry together while improving your bottom line.
US FOR ONE DAY, OR BOTH,
your
Spot possible water sanitation issues early on. By:
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Dr. Chevonne Dayboll & Dr. Sarah Jandricic
Issues 10 PGR overapplications and what to do about them
Favourites 12 Varieties are put to the test in landscape and containers
Less Phosphorus 34 Researchers lower P delivery by 75 per cent in mums
The unexpected benefits of insect screening Perks include a more stable climate and lower disease pressure
BY GRETA CHIU
Calibration matters
pH and EC readings are only useful when they’re accurate
BY HEIDI LINDBERG
Preventing pests in this day and age Experts share pain points, costly mistakes and tech solutions
Q&A WITH CHARLIE MCKENZIE & ALLISON KOPF
As I’m writing this, it’s International Women’s Day, which seems to have coincided with a higher-than-average level of female-focused content in the media. One particular CBC News story highlights a shortage of longterm women’s shelters in Canada.
As the national news outlet reports, short-term crisis shelters have stay restrictions ranging from 21 days to three months. But because there’s a shortage in second stage shelters and safe, affordable longerterm housing, many requests for help have been turned away. And while some provinces offer priority to abused women in finding affordable housing units, a roof over their head is not a complete solution for someone who needs employment, counselling services and other forms of support to turn their lives around.
So, why not horticulture?
One might argue that much of the required labour for horticulture is seasonal, and that the majority of Canadians would rather have longer-term employment with more stable income. However, data from
that may require handling about 50 Ib, and a team player mentality.
Sure, earnings are minimum wage, but working in horticulture can allow for substantial skill acquisition and opportunities for promotion, not to mention the reported benefits to health and mental well-being from being around plants. Greenhouses are also often located just outside of urban centres, and employees can take advantage of lower cost housing but still be within reach of assistance and other community services.
The seasonal agricultural workers program (SAWP) in Canada is a great example of how an established employment program can help break the cycle of poverty. Just watch the Canadian Horticultural Council’s ‘Heartbeat,’ a series of videos where seasonal workers share their stories of life in Canada. Some return to the same farms season after season to support their families and as a result, have been able to financially support their children through school. For their next generation, it’s a chance
For their next generation, it’s a chance at a different life.
Statistics Canada’s Labour Force Survey shows that the fraction of people who have temporary employment in Canada has grown from 11.8% in 1998 to 13.3% in 2018.
While there is a need for more hands on deck during peak months of the season, a glimpse of the job postings on LinkedIn reveals a number of ongoing wanted ads for greenhouse workers and general labourers – many of which are fulltime positions. In almost all cases, no formal education is needed – just a willingness to learn, the ability to perform repetitive, physical tasks
at a different life. Plus, as part of the program requirements, workers are provided with daily transportation to and from the workplace as well as affordable accommodations.
By that same token, would it be too farfetched to connect Canadians in need of lower-cost housing, a job and a new life with opportunities offered by horticulture?
Editor’s note: For readers who received the print calendar polybagged with our December 2019 issue, please check the dates of any event before making plans, as some have been rescheduled due to COVID-19.
es.bayer.ca
After more than three decades of public service with the provincial government, David Woodske retired from his role of 22 years as the provincial industry specialist for ornamentals and greenhouse vegetables.
“To get to go around and talk to growers oneon-one,” says Woodske as he reflects on his role, “I will certainly miss that.” Another highlight was collaborating with ministry colleagues and industry
partners to resolve the sectors’ challenges. “It was always very rewarding.”
Though he first began as the province’s nursery specialist in 1998, Woodske’s position grew to include floriculture and greenhouse vegetables. In 2016, the BC Greenhouse Growers’ Association presented Woodske with the Meritorious Service Award in recognition of his contributions to the industry.
Full story at greenhousecanada.com.
Nominations for Greenhouse Canada magazine’s annual awards are open once again.
Top 4 Under 40, sponsored by Paul Boers and Prins, recognizes young members in the greenhouse horticulture, related equipment and technology sectors, and allied trades.
Grower of the Year recognizes a greenhouse grower for their innovative thinking, hard work and dedication to their craft. Nominees must be actively involved in
their operations. No age restrictions.
Created to celebrate horticulture and the budding young generation, nominations are often submitted by fellow growers, colleagues, or supervisors who wish to recognize the efforts of their peers.
This year, winners will be revealed at Grower Day in St. Catharines, Ont. (June 16) and at new Grower Day West in Abbotsford, BC (June 23). Visit growerday.ca for details.
More than 24 different scholarships ranging from $500 to $6,000 are now being offered through the American Floral Endowment (AFE) to undergraduate and graduate students. Applicants must be American or Canadian citizens or residents and pursuing floriculture or horticulture studies at a U.S. or Canadian institution.
“AFE strives to support the next generation of industry members in any way we can. One of the ways we do this is through awarding scholarships to help ease their financial burdens,” says Greg Royer, chairman of Royers Flowers & Gifts and AFE Education committee chair.
Scholarships are available for students interested in different areas of horticulture, including marketing/sales, agribusiness, floral design, greenhouse production, ornamental horticulture, integrated pest management, floriculture research/education and more. Applications are due May 1, 2020.
Nominations close May 8, 2020. Submit one at greenhousecanada. com/awards
Last year, Greenhouse Canada teamed up with sister publications Grow Opportunity, Canadian Security and Canadian Packaging to expand Grower Day into a twoday event.
As Greenhouse Canada moves into its 40th year in print, the publication is celebrating four de-
cades of content with its readers in ON and BC and bringing Grower Day with them.
At each location, the first day will continue to be dedicated to the greenhouse floriculture and vegetable sectors. A full day of speaker sessions will be accompanied by a cozy tradeshow of industry exhibitors. The second day will focus on the business of cannabis cultivation.
For more, visit growerday.ca.
Source: Statistics Canada
From 2017 to 2018, national greenhouse area grew by 2.9%
Year-over-year growth, by material:
Proportion of greenhouses by material
Danziger is bringing a new combo program to the North American market. The program features curated combos that pair well-matched and well-behaved varieties together,
designed to create stunning combos for consumer appeal. These two- and three-plant recipes work together to create long-lasting baskets that perform throughout the season. With DuraBella, consumers won’t end up with combinations where one plant chokes out another as the basket or container matures.
Pictured: Hunka Burning Love danzigeronline.com
With limited options for foliage plants from seed, growers often use coleus to add interest and texture. The new Sol Collection is a foliage celosia with relatively fast production time and no downy mildew issues. It holds well at
retail and expands the options for consumers looking for sun-loving foliage accent plants for patio planters, as well as quick-growing, low, shrub-like plants. Foliage tends to be more green when kept indoors and turns to burgundyred when the plant is left outdoors for at least 1 to 2 weeks. Foliage also tends to curl due to genetic factors and can be modified by climate conditions. 3 to 4 weeks plug time, 7 to 10 weeks from transplant to finish. 25-36 cm tall, 25-41 cm wide. panamseed.com
Strong yet beautiful, tough yet elegant. Durabloom has been developed to withstand all the surprises that the Canadian summer brings to gardens. The interspecific breeding yields extremely strong root structure, ensuring consumer success.
This variety is a miniature flowering, spreading Petunia perfectly suited for basket, mixed container, and premium pack programs. Less daylength sensitivity provides extra early flowering in 9-10 weeks from sowing, even under short day conditions. Tidy plants
For 2021, LaBella Gigante Pink Bicolor is a new addition from Beekenkamp. The extra large flower on this dahlia suits bigger pot sizes of 10” or more. Branches very quickly and can easily
hold longer at retail than traditional trailing Petunias and don’t overgrow companions in mixed containers. Extremely free flowering all summer long, even under difficult garden and weather conditions. Spreading habit. 15-25 cm tall, 46-61 cm wide. syngentaflowers-us.com
be used for landscape. The enormous pink bicoloured flower not only attracts the human eye, but also draws the attention of butterflies and bees in gardens and on patios. beekenkamp.nl
Though Proven Winners won’t be taking part in CAST this year, this new variety is too gorgeous to go unnoticed. Selected for its excellent basal branching, long-lasting bloom performance and large, full flowers, its tangerine orange blooms with faint red halos remain attractive as they
age. Earlier to bloom, lasting from midsummer to late summer, this variety is deer-resistant and attracts pollinators. Produced from tissue culture to ensure uniformity in colour and habit. Part sun to sun, zones 4-8. 46-56cm tall, 41-51 cm wide. provenwinners.com
Great for mixed containers with friends like Aloha Calibrachoa, Empress Sun Verbena or Big EEZE Geranium. Use for colourful landscapes, or on its own in decorative planters. Full sun to part sun. 20-30 cm tall. dummenorange.com
A near ten-year breeding program has delivered a first for North America’s gardens. The Dakota series is a true hirta, but
unlike all other hirta, they are daylength neutral and hardy to zone 5. The first daylength neutral and perennial hirta to hit the market. Huge flowers of five to six inches bloom daily through the growing season, with one plant producing twenty to thirty blooms at a time. green-fuse.com
JIM KRUGER | fine-americas.com
How to avoid it, and what to do if it happens.
It is any professional grower’s worst nightmare. Unfortunately, many have experienced that moment of recognizing plants which have suffered from a plant growth regulator (PGR) overapplication. Maybe it happens because label instructions are misunderstood, or because of a miscommunication within the production team. Perhaps an inexperienced applicator miscalculates the application. Even an experienced applicator can mix up the concentration calculation.
When overapplication happens, sometimes the signs are immediately obvious. Other times, they may take a while to appear. If you’re lucky, the applicator realizes right away, and you can address it as soon as possible.
Catastrophic could be the word used to describe these situations. Expensive delays waiting for stalled plants to recover. Plants that keep growing but won’t flower. Phytotoxicity, which may appear as necrotic spots, yellowing or discolouration. Leaves that crinkle or are darker green than normal. Severely stunted growth. Leaf distortion. Missed windows for sales. And in the absolute worst case scenario, having to discard an entire crop and take a hard hit to the bottom line.
To avoid a PGR overapplication, always start by reading and following label directions. Encourage growers and applicators to take extra time for calculations. PGR rates vary by cultivar and by plant type, so it is extremely important to refer to any recommendations that the plant breeder or supplier provides as well.
Equipment can also make a difference. Always calibrate before application. Perform regular maintenance on nozzles, hoses and other parts to ensure they’re operating at peak level. And be sure to fully flush each unit before switching to another product.
Carefully consider how many people you have involved in your application strategy. Miscommunication is one of the most common causes of PGR overapplication – one applicator doesn’t realize that another has already done the application, for example. It’s best if you can limit both the number of people who apply and the number of decisionmakers on application timing.
Just because it’s been done a hundred times doesn’t mean number one-hundred-and-one will be fine. Complacency kills calculations very quickly. Practise application techniques, as well as how
to calculate. An easy way to practise is by using water to apply in an area without crops. Check the math, then recheck it. Be sure volume and rate calculations are correct. Refer back to notes from previous applications. Tools like the free PGR Mix Master calculator, developed by Dr. Brian Krug, greenhouse floriculture specialist at University of New Hampshire Cooperative Extension in partnership with Fine Americas, can be invaluable in avoiding overapplication. The calculator provides an easy way to calculate the right rate for sprays and drenches with some of the most common PGRs. Simply choose the PGR you’re using, click metric measurement, select the final solution amount and PGR concentration, then click Calculate. It is accessible at e-gro.org/mixmaster.
Even the most experienced growers can have a misstep. Ongoing research has revealed a way to rescue crops with Fresco, a known PGR. This rescue application is being successfully used in the States. Currently, Fresco is labelled in Canada for use on lilies (Easter, asiflorum hybrids, Asiatic and oriental) to prevent yellowing and senescence of lower leaves and to delay flower senescence. Work is ongoing to expand the uses for Fresco in Canada. Fresco is a combination PGR with two active ingredients: BA (benzyladenine) and GA (gibberellic acid). It contains 1.8% GA 4+7, which enhances internodal elongation, and 1.8% 6-BA, which stimulates lateral or axillary shoot growth. These active ingredients let Fresco stimulate growth in two very different but very complementary ways.
Gibberellins help plants stretch or grow taller by encouraging cells to elongate. Likewise, cytokinins are phytohormones that stimulate cells, but they’re encouraging them to divide, thus increasing branching and plant growth. Combined, the two plant hormone groups encourage controlled, structured, uniform growth to produce plants that are fuller and more marketable. This dual action, researchers discovered as they were refining Fresco’s use as a drench, wakes the plant’s pathways such that they help plants recover from overapplication or a stall with very controlled growth.
The bottom line is that overapplication will be something many growers face in their careers. The answer to prevention lies in vigilance for communication, maintenance and calculation.
Jim Kruger is regional sales manager, eastern Canada, for Fine Americas.
Recent varieties and IDMresistant impatiens were put to the test. Here are noteworthy highlights from three container and landscape trials in Ontario.
BY RODGER TSCHANZ
Multiple open houses for the public and the horticultural industry were held at the trial sites in Guelph, Milton and Burlington, Ont. during the first two weeks of August 2019. Grown in either containers or ground beds, the annual plants described here attracted the most attention from visitors to the gardens during those weeks. They also exhibited exceptional performance during the growing season. Cool weather and extremely wet spring conditions ultimately delayed planting of the 2019 trial beds by approximately two weeks from what normally would have been expected. That said, as the
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growing season progressed, the growing conditions improved and allowed plant growth to catch up, providing a terrific floral display in August.
[1] Pink Zebra Ornamental Corn: With its unique texture and tri-colour leaves, this ornamental corn by PanAmerican Seed was one of the most popular landscape annuals last year. Although introduced to the industry over a year ago, this was the first time Pink Zebra appeared in the Guelph trials. As it grew, it produced lots of tillers giving it a compact, bushy appearance with plant height
SuperElfin [left] succumbed to impatiens powdery mildew at the Royal Botanical Gardens. Beacon [middle] and Imara XDR [right] continued without symptoms.
reaching only 105-136 cm and spreading 70-87 cm at the end of the season. Dark brown-purple tassels started to appear in mid-August, and plants in the trial maintained ornamental quality up until early September before starting to senesce. This plant performed well in both containers and in the ground. Pink Zebra was grown successfully in one-gallon pots for use in garden displays for the Canada Blooms garden show in 2019.
[2] Superbena Sparkling Amethyst Verbena: This trailing verbena from Proven Winners was the most popular “crossover” annual for 2019, demonstrating exceptional ornamental performance in both containers and landscape. This purple-amethyst and white-bicoloured selection had great heat tolerance with summer-long bloom and appeared resistant to powdery mildew. By the end of the summer, the trial’s plants had spread to approximately 1 meter in diameter and mounded to a height of 22 cm. For mixed containers, this selection could function as a great “spiller” in combination with equally vigorous plant selections.
[3] Move2 Joy Pink Begonia: The favourite container-grown begonia for 2019 was Move2 Joy Pink from Dümmen Orange. Both the pink and white cultivars in this series were trialled under part-sun conditions and performed equally well in both landscape and containers, although the pink colour attracted the most attention. Both cultivars produced a crown of blooms that, at its peak, completely covered the large leaves for great floral impact. Move2 Joy Pink reached garden heights of 30 cm with a plant spread of 40 cm. Individual flowers were seen to reach diameters of 6.5 cm.
[4] Sincerity Dahlia: With its large bicolour lavender and white blooms, Sincerity from Syngenta was the most popular dahlia in the trial. It had moderate vigour with plant height reaching 52 cm in the landscape and spreading to 70 cm. Bloom diameter can reach 16 cm. It was named Plant of the Year for
[5] Echibeckia Summerina: Pacific Plug and Liner’s Echibeckia Summerina is the name given to a series arising from the intergeneric cross between Echinacea and Rudbeckia. Although its genetic heritage would potentially make this a perennial in southern Ontario, the hardiness from the breeder only claims adaptation to USDA Zones 6 or 7. There are eight colours available in this series; each has a different flower colour pattern, petal shape or plant habit. The colours range from dark brown-maroon to orange-yellow. The habit is generally compact and well suits container applications. Visitors to the 2019 trials picked container-grown Summerina Blazing Fire as one of their favourites.
[6] Foxglove Pink Panther: The foxglove Pink Panther from American Takii was very popular to visitors in both containerand landscape-grown scenarios. Pink Panther had a long bloom period with trial specimens that were seeded in early April, flowering 13 weeks later in July and continuously until the killing frost in late October. Its growth habit was compact, with multiple flowering stems. Flowering spikes ranged in height from 33 to 81 cm, and individual plants spread to 50 to 57 cm by the end of the growing season. Individual flowers were small, measuring 2.3 cm in diameter by 3.5 cm in length – smaller than those found in the Camelot series of foxglove, for example. American Takii has not been promoting this plant as a perennial but it certainly is cold-tolerant. Winter hardiness evaluations for this selection have been taking place in the Guelph trials during winter 2019-20.
[7] Capsicum Onyx Red: Another popular landscape selection from American Takii was the ornamental pepper Onyx Red. It was selected as a national winner in the 2018 All-America Selections judging season. The dark purple foliage and small round purple fruit that ripens to a brilliant cherry red is reminiscent of Black Pearl but at half the height. Its growth habit is very
suitable for both container and landscape applications. End-ofseason landscape height in Guelph was 27-36 cm with a spread of 36-41 cm.
[8] ColorBlaze Wicked Witch Coleus: The most popular coleus from both the container and landscape portions of the trial was ColorBlaze Wicked Witch from Proven Winners. The leaf has a dark purple centre with a green margin. The selection went through the entire growing season without blooming. End-of-season landscape height in Guelph was 53-56 cm with a spread of 57-64 cm.
PUTTING DISEASE-RESISTANT IMPATIENS
This article wouldn’t be complete without mentioning the results of last season’s trial on impatiens, testing their performance against impatiens downy mildew (IDM). Two new series of IDM-resistant Impatiens walleriana are now available: Imara XDR series from Syngenta and Beacon from Ball. Cultivars of
these two series were grown alongside two cultivars of SuperElfin impatiens, which was an older series that was once widely grown before IDM came along. Because SuperElfin impatiens are highly susceptible to IDM, they were planted beside Beacon and Imara XDR as a control. The impatiens were planted in containers (Vineland and Guelph trial sites) and landscape (Guelph, Milton and RBG trial sites). Garden performance was excellent for all three series until evening temperatures started to drop in September. At this time, we started to see a decline in SuperElfin White, and a few weeks later, in SuperElfin Orange as IDM infected landscape plantings of these varieties. While SuperElfin selections succumbed to the disease, both Beacon and Imara XDR impatiens continued without IDM symptoms. It is interesting to note that all three series were free of IDM symptoms when grown in containers in the 2019 trials.
Rodger Tschanz is the trial garden manager at the University of Guelph. He can be reached at rtschanz@uoguelph.ca.
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Among its insect blocking abilities, insect netting offers unexpected advantages for greenhouse climate control and ongoing pest management practices.
BY GRETA CHIU
Allegro Acres hasn’t seen a single pepper weevil since they installed insect netting screens.
Gene Ingratta, owner and operator of the vegetable greenhouse operation in Ruthven, Ont., says they not only covered the pepper production area, but screened every point of entry into the farm as well. “It’s the first, last and only line of defence to properly control pepper weevil,” he says.
Since the majority of its lifecycle takes place inside the pepper fruit, the weevil isn’t just hard to spot, it’s extremely difficult to control by any means, says Ingratta. “You can scout for it but that’s an uphill battle in the middle of summer when fruits are developing fast, and work load is already at its peak.”
According to Ontario Greenhouse Vegetable Growers (OGVG), a surge in the pepper weevil population led to losses of over $67 million for Ontario’s greenhouse-grown peppers in 2016.
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“This is a relatively new adoption in our area [that was] largely triggered by the pepper weevil” says Cara McCreary, greenhouse IPM specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs. “Prior to 2017, there were very few operations that had netting. The select few who did were more organic producers because their tools were limited to begin with.” Screen installations promptly rose in the two years following the pepper weevil outbreak.
At first, growers were hesitant to install insect netting screens, concerned about their impact on the greenhouse climate. Depending on the size of the mesh, screens can reduce airflow within the greenhouse and lead to a rise in temperature and humidity. This was of particular concern, given how hot and humid it can be in southwestern
Insect netting for Allegro Acres’ glass range was installed by Countrywide Industries, while netting for their poly range was installed in 2016-2017 by Ruthven General Construction, who oversaw the two.
Ontario. However, McCreary notes that the positive feedback she’s received from growers have far outweighed the challenges to climate control, which can be managed to a certain degree with fans and forced ventilation.
For Allegro Acres, Ingratta specifically chose mesh dimensions that offered pepper weevil exclusion without compromising the greenhouse climate. “Anything smaller or tighter in size would start blocking too much airflow,” he explains. “And anything smaller than that [size] can be fairly easily controlled with biologicals.”
The screens have also helped block the rain and some of the wind, allowing Allegro to open the vents more while minimizing plant movement. “On rainy days without screens, the vents would be open 10 per cent. With screens installed – 55 per cent,” he says. They experimented with vent openings over the course of two to three months, increasing them a little more each time. “If it’s not a driving wind, those vents could be 70 per cent open.”
There’s been a positive impact on light-induced plant damage as well. The
screens are able to diffuse direct sunlight streaming in through the open vents, reducing the incidence of crop burn.
Overall, the insect netting has helped avoid spikes in temperature and humidity on rainy days, which could otherwise promote the spread of powdery mildew. Coupled with better growing strategies,
When choosing a mesh size, think “what do you really want to exclude and what are you willing to allow in.”
the insect netting has drastically reduced the risk and spread of powdery mildew for their operation.
“Fungal diseases like powdery mildew are influenced by poor air circulation, so being able to open vents wider during compromising weather can have a positive effect,” McCreary explains. “Even when the temperatures are colder out-
side, [growers] can potentially open their vents wider than they normally would because the screens minimize or reduce the amount of cold air coming in.”
By excluding insect pests, birds, and bees, the screens can also help prevent the introduction of vectored diseases. However, their ability to keep bees and beneficials inside the greenhouse has proved to be advantageous as well, and could be an opportunity for use in other crops. “When temperatures are nice and there are food sources outside, [bees] may leave the greenhouse to go forage, so this way they stay inside,” McCreary explains.
“Generally speaking, when you choose a mesh size, you want to think about what you can live with. What do you really want to exclude and what are you willing to allow in?” says McCreary.
The larger mesh sizes that exclude pepper weevil would also help keep out some of the larger flying insects such as looper moths, European corn borer and Lygus. “If you go smaller, you’ll have a greater impact on your environment
inside, but you can exclude more [pests] like aphids or whiteflies.” An even smaller size could exclude thrips, but would have a much greater impact on the temperature and humidity inside. Plus, there are many effective beneficials available for thrips and aphids.
Insect screens should ideally be installed in a clean greenhouse, as the netting can trap harmful insects inside and ones that breed through the winter months. Spring is a good time to install them before temperatures begin to rise and potential pests wake up from their overwintering sites, and growers start to open the vents a bit more, McCreary says.
Screens should also be inspected regularly and breaches taken care of promptly. At Allegro Acres, staff clean out any trapped dirt and debris using a power washer and plain water about once every two years. They found that washing the screens in June helped maximize airflow through the summer and minimize impact to the greenhouse environment. If the screens become more dirty at the end of the summer or going into the fall, it matters less as temperatures start cooling off and the likelihood of opening the vents all the way diminishes as they head into winter, explains Ingratta.
Allegro Acres’ insect screen supplier, Holland Gaas, says their products are made from UV-stabilized polyester monofilament threads and are designed to last for a number of years – no replacements have been needed since their company’s inception. In the Netherlands,
insect screening is common for breeding nursery greenhouses and seed companies, “but it’s also applied more and more in floriculture and vegetable cultivation,” says Karin Dahmeijer of Holland Gaas.
“What we see is that insects are spreading through different countries and continents, or that they behave differently due to changes in climate.” When deciding on whether to install insect netting or which mesh size to use, growers may want to consider targeting pests that have outbreak potential. For example, mesh openings of 0.8 mm x 0.8 mm will not only exclude the pepper weevil from entering the greenhouse, but Tuta absoluta as well, she adds.
Holland Gaas has worked with a number of Canadian growers over the years. Because of this, their managing director, Marcel Schulte, says they continue to tweak their products for improved performance in various climates. “Due to different weather conditions, different guiding systems have to be used,” he says, explaining that the system ensures proper folding of the netting screens as the vent closes. To stand up to high winds, such as those experienced in the Windsor-Essex region, the supplier has developed a new, stronger stainless steel guiding system. The installation process is not one-size-fits-all either. Schulte says they’ve engineered different installation solutions for each type of greenhouse and often customize them for different situations.
Price-wise, purchase and installation costs can vary. “A lot of it has to do with
the current greenhouse structure and how much retrofitting needs to be done,” McCreary explains. “If they’re older greenhouses that need a lot of retrofitting, then it’s going to be at the higher end. Some of the new greenhouses that are being installed [are] working it into their original design.”
Though the upfront costs can be steep for larger acres, Ingratta says the benefits multiply in the long-run. His crop now finishes cleaner and cleaner with every season, drastically reducing the inputs and efforts needed to manage their pest challenges each year. It’s allowing them to finish strong, and more importantly, start the next season with little to no pest pressures present. “It’s like having a little force field protecting the farm,” he says, while also reducing the risk of developing resistance. “No pest is going to build up resistance to screens.”
Though pepper weevil pressure has been low in the past two years, insect screening seems to benefit the greenhouse in many different respects, including a more stable indoor climate, fewer chemical inputs and more effective biocontrol. “Biocontrol programs can be much stronger when there aren’t as many pests flying around,” McCreary points out. While insect netting screens generally won’t be 100 per cent perfect, as one or two pepper weevils will find a way to sneak in, the netting still makes a substantial difference. “It all results in potentially fewer pesticides being used …[and] makes for a stronger pest management program.”
Does dry soil promote root growth? Research and greenhouse experience would disagree.
BY ALBERT GRIMM
Grower knowledge is permeated by greenhouse lore that is enduring but not always accurate. One of these myths claims that dry soil promotes root growth, because roots are forced to ‘search for water’. Consequently, growers dry their crops into mild water stress to aid the development of root systems. The problem is that practically all plants disagree. We know that moisture stress and dry/ wet cycling produces less root mass and branching, not more. This is confirmed by close-to-home research at the University of Guelph.
Plants develop roots where they find the best conditions for water and nutrient uptake. Root hairs, the active parts of most roots, work best
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when they are continuously covered by a thin film of liquid water with a comparatively large air-filled space beyond the water layer. In other words, roots place themselves exactly at the boundary of a wet surface and a body of air. Availability of water stimulates root hair development, and the air is necessary for oxygen supply, because oxygen must continuously dissolve into the water film covering the root hairs. Water moves into the cells and brings along necessary oxygen. Root hairs suffocate if they are not surrounded by air-filled spaces and if no oxygen dissolves in the water that enters the plant.
Substrate that is too wet or does not hold air spaces creates thin, rapidly
On a sunny day in late May, it may take more than 15 irrigation cycles per day, with 1-2 ounces of water per cycle to maintain fully mature hanging baskets at moisture level 3. Tight water control allows us to create sturdy, droughtresistant plants with excellent garden center and consumer shelf-life.
elongating roots without any hairs. If the substrate is too dry, adequate root hairs will not develop and root development slows down. So, roots do not search for water, but for conditions that are ideal for root hairs.
The plant perspective of happy roots allows us to use purpose when we apply water to a crop. However, before we can do so, we need a method to measure soil moisture that allows us to compare between different crops and different seasons.
Soil colour, experience-based judgement, and the often-clichéd feeling in one’s gut merely represent a grower’s idiosyncratic perspective of how wet or dry any substrate should be. Neither of these provide us with any plant perspective. We need a reliable measure of how much water is available in any given substrate before we can assess the effect on roots. For this purpose, we have developed a 5-step moisture scale for peat-based container substrates, where level 1 is dry and level 5 is wet. This is how we define these moisture levels:
Moisture Level 5: The substrate is saturated with water. We can easily squeeze an abundance of water out of the substrate. When a small amount is placed on a sheet of paper or cardboard, it leaves clearly visible droplets or a wet spot, even when no pressure is applied. Plant Experience: Roots do not find enough waterto-air boundaries, because all capillaries in the substrate are flooded.
Moisture Level 4: The substrate is at moisture capacity, but it does not contain any freely draining water. The substrate looks wet, and we can squeeze out some droplets of water, but it does not leave any wet spots when it is placed on a sheet of cardboard. Plant Experience: Roots find plenty of water-to-air boundaries, because the capillaries are filled with air. Water uptake is unrestricted. As we increase moisture beyond level 4, the water-to-air boundaries gradually disappear because the capillaries begin to flood.
Moisture Level 3: The substrate changes colour from dark/black to light/ tan and contains visibly less moisture. The substrate still feels moist to the touch, but we can no longer squeeze out water unless we use extraordinary effort. Plant Experience: Roots find plenty of water-to-air boundaries. Water uptake is
The roots in this rockwool slab place themselves exactly at the boundary of the water film, which forms where the water drains from the substrate onto the inside of the plastic cover.
slightly restricted, and the root system is expanding with healthy root hairs. Practically all ornamental crops develop optimal root systems if substrate moisture is maintained at level 3.
Moisture Level 2: The substrate is very light/tan in colour and does not contain any visible moisture. The substrate feels dry to the touch. The crop is under discernible water stress, but it does not wilt. Plant Experience: The root system is working at full capacity to extract water from the substrate. This is about as dry as we will take most crops without fear of damaging them permanently. If we decrease moisture beyond level 2, the residual water films disappear.
Moisture Level 1: The substrate is completely dehydrated. It loses its elasticity, visibly shrinks, and often separates from the container. The crop is under severe water stress and loses turgor. Plant Experience: Many sensitive crops are permanently damaged by these conditions.
Moisture Level 3 is the sweet spot. Almost all containerized crops would be
perfectly happy if we could maintain this level all the time. It offers a perfect balance of moisture to air in the substrate, and plants can comfortably regulate water uptake to balance turgor pressure. If we increase moisture to level 4, water-to-air boundaries and oxygen supply will remain intact, but water is available for uptake with almost no resistance. That’s OK if the plants can evaporate the water at the same rate as roots pump it into the system. However, when the greenhouse climate changes rapidly, e.g. at nightfall after a sunny day, the roots may not be able to reduce uptake quickly enough, and as a result of increased turgor pressure, cells begin to stretch, internodes elongate, and foliage expands. For some crops this may be advantageous, but most ornamental growers are in the business of selling compact canopies underneath abundant flowers and stretch is not desirable.
If we reduce moisture from the sweet spot towards moisture level 2, we make it harder for the plant to take up water and nutrients. This reduces stretch and canopy expansion, but it also reduces root growth and photosynthesis, particularly during warm, bright weather when plants need a
Crop watered 3-4 times per week
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Crop watered 3-4 times per day
Tight control of substrate moisture levels requires frequent irrigation with small volumes of water.
constant supply of water for evaporation.
HOW CAN WE USE ALL THIS KNOWLEDGE TO MANAGE PLANT HEALTH AND HABIT?
Growers should not just water plants. Growers should operate root systems. We need clear objectives before we can make purposeful decisions about watering plants. Do we want to optimize biomass production, or are we concerned about too much canopy? Can we trade off stress tolerance for optimal photosynthesis, or do we need tough plants that survive for weeks in a hot, dry garden center without being watered regularly?
Our target moisture level should match our objective. Moisture level 3 is adequate for most crops, but we can increase drought tolerance if we are to operate closer to level 2. If we have a greenhouse optimized for biomass production, we may want to aim for moisture level 4 to maximize potential water uptake.
The practical challenge is to develop irrigation methods that achieve our target moisture level with only minimal fluctuation. For uniform substrate moisture, we must water as frequently as our irrigation system allows with as small a volume per irrigation as possible. Infrequent watering requires larger volumes of water per irrigation and results in larger fluctuations of substrate moisture between cycles. If we simply wait until the crop is dry before we water thoroughly, we get maximum moisture fluctuation and are no longer able to manage the root system.
Grower panic is the most common cause of water-related crop damage. Let’s imagine
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Root hairs develop along active sections of healthy roots. You can learn how to read roots and substrates by observing very closely where you find these active sections on the root systems in your crops. Typically, there is a large substrate capillary nearby. In dense or saturated portions of the substrate, roots are comparatively thin and less active with fewer root hairs.
that you arrive at the greenhouse and one of your crops is wilting. You realize that you will be in big trouble if anybody else sees such a sad picture. You get grower panic, and you rush to get water to these wilted plants as quickly and as thoroughly as you can manage. A few days later, the roots are dead, and the quality of this crop is toast. Such damage would not have been caused by the wilt, but by the water.
Severe water stress followed by excessively wet conditions is deeply problematic for plants. The tender root hairs of moisture stressed plants are using enormous force to pull out the last drops of water film from dry soil. If we suddenly inundate the substrate and the roots with an abundance of water, these root hairs do not have enough time to shut off their water pumps. Water rushes into the cells, and the resulting internal pressure bursts their tender membranes. The root hairs
explode. The resulting wounds allow diseases like Pythium to establish, and this is the key trigger for water molds. Even if the roots survive unscathed, the sudden change in turgor pressure can cause a variety of other undesired physiological symptoms on the plants.
The proper way to re-hydrate any severely dry or wilted crop is slowly. Initially, give the plants no more than a few drops of water, preferably over the foliage to reduce stress. After 20 minutes, give them a few drops more, and let the roots know that water is coming. Give the roots time to adjust, and then re-hydrate the soil very slowly by watering repeatedly over an 8-10 hour period. Doing so is more effective at preventing root rot than a fungicide drench.
Albert Grimm is head grower at Jeffery’s Greenhouses in St. Catharines, Ont. He can be reached at albertg@jefferysgreenhouses.com
pH and EC values are important, but they’re only useful if your meters are accurate.
BY HEIDI LINDBERG
Spring of 2020 is in full swing! Propagators are shipping and plugs are being transplanted. With all of the activity in the greenhouse, it is easy to forget the basics, such as making sure your pH and electrical conductivity (EC) meters are calibrated correctly.
In my experience, growers are carrying out their daily activities until they see a nutritional problem in the crop – and then it is time to dust off the pH and EC meter. The measurements you take with your meters are only as good as the calibration. Remember that pH is based on a logarithmic scale, so a pH of 6.0 is 10 times more basic than a pH of
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5.0. What appears to be small shifts in pH are actually larger than you might think and may quickly affect the nutrient uptake of your plants. For example, I had not calibrated my meter in over 6 months and the readings were 0.5 units off. If your pH and EC meter also provides you with an inaccurate reading, you might falsely make a management decision about your spring crop – costing you time and money – and you still will not achieve your desired results. There are a variety of EC and pH meters on the market, but the meter that I have is a Hanna Instruments HI 9313-6. Michigan State University Extension recommends that
Place the tip of the probe into a standard solution and adjust the calibration dial until the reading on the meter matches that on the standard solution bottle or packet.
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you calibrate your meter before every measurement session, but at a minimum calibrate your meter a couple of times throughout the season. Calibrating your meter is quick and easy. Simply follow this step-by-step process:
1. Gather all materials needed to calibrate your pH and EC meter: pH and EC meter, storage solution, standard solutions, distilled water, and beakers or cups (if applicable).
2. If you have not used your pH and EC meter in a while, follow the manu-
facturer’s instructions on how to get it ready to go. First, check to see if the probe needs a new battery. After a long period without use, the electrode in the probe of the meter will have likely dried out. If the probe dried out but still works, soak the probe in a storage solution for a minimum of an hour (for example, HI70300 Storage solution).
3. Make sure your standard solutions are not expired! Frequently, we are tempted to draw out of the same
bottle for years on end. Be careful, as the integrity of the solution may have changed over time. The manufacturers often sell these calibration solutions in variously sized bottles or as convenient individually packaged disposable sachets.
4. If your standard solution came in a larger bottle, pour the solution into a clean, dry container such as a small cup. If your standard solution came in an individual sachet, place the electrode directly into the packet. Never dip the probe directly into the larger bottle as the known pH or EC will become inaccurate over time. Also, growers should take note that the pH of the solution changes with temperature, so be sure to check the temperature of the solution before calibrations.
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5. Once you have “re-wet” the probe, you will now need to calibrate the pH of the meter. For my meter, I needed the pH standards of 4.01 and 7.01.
6. Rinse the tip of the probe with distilled water or reverse osmosis (RO) water prior to dipping it in any standard solution.
7. After inserting the electrode in the standard solution, adjust the dial to make sure your meter is reading the pH of the known 7.01 standard (see photo).
8. Rinse between calibrations with distilled water or RO water.
9. Now calibrate your meter using the 4.01 standard solution. Similar to step 6, adjust the calibration dial so that your pH meter reads 4.01.
10. Finally, calibrate your meter to a known EC. My meter displays the number in mS/cm, but the calibration packet is labelled in µS/cm (1413 µS/cm, in my case). Remember, 1413 µS/cm is equivalent to approximately 1.41 mS/cm. Place the tip of the probe into the EC standard solution and adjust the EC calibration dial to the known standard (1.41 mS/cm). You are now ready to use your pH and EC meter! For guides and videos on meter calibration, crop-specific factsheets (annuals, vegetables/leafy greens, and potted crops), and pH and EC management recommendations, check out fertdirtandsquirt.com
Heidi Lindberg is a greenhouse and nursery educator at Michigan State University Extension. She can be reached at wollaege@ msu.edu.
It may be a tired saying, but prevention really is worth a pound of cure (or fungicide) when it comes to heading off disease issues.
BY DR. CHEVONNE
DAYBOLL AND DR. SARAH JANDRICIC
BELOW
Ensure that irrigation lines are cleaned before new crops go in.
Ever wonder how water-related disease issues just seem to pop up out of nowhere? You’ve never had a problem before, but suddenly things just aren’t looking right.
The truth is that problems often go unnoticed while pathogen levels are low. Or, problems can suddenly appear if a new pathogen is brought in through a variety of routes. Knowing potential inoculum sources and practising good preventative measures can help to reduce the risk of a big problem down the road.
Your irrigation water can be a potential source of inoculum. In your own operation, you might rely on rainwater, well water or city water. Your water sources might vary based on their purpose in the greenhouse: for use on the potting line or production irrigation, for example. The source might also change throughout the year, depending on your production needs and the availability of any given source.
Knowing the quality of all your water sources is a must for avoiding problems. The cost of a regular water test may be worth it if you can avoid costly applications of corrective products over the season. Aim to take, at minimum, seasonal samples of your water to ensure that it is free from contaminates. Knowing the attributes of your irrigation water can also help you to tailor your fertigation program – a win-win!
Your water storage method should also be considered. If you rely on rainwater, you might collect if off the greenhouse roof and store it in cisterns for later use. When was the last time you
University of Guelph researchers reduced phosphorus use by 75 per cent in greenhouse chrysanthemum production, with no change to market quality.
BY DR. BARRY J. SHELP, WILLIAM J. SUTTON AND EDWARD J. FLAHERTY
For plants, phosphorus (P) is a crucial component of nucleic acids, phospholipids and intermediates in many metabolic pathways, and is involved in the control of cell signaling pathways in response to developmental and environmental cues. Inorganic P (Pi), taken up by plants in a form known as orthophosphate, is often the major nutrient limiting plant development and yield. In natural soils, Pi availability is generally low, depending on various factors such as fixation in the soil, leaching and conversion into organic forms that are not readily absorbed by plant roots. These same factors contribute to the inefficient use of applied fertilizer-Pi by agricultural crops, which can lead to overuse of fertilizer-Pi and the eutrophication of terrestrial and aquatic ecosystems. More efficient fertilization strategies and technologies are required to minimize environmental concerns.
Subirrigation systems were developed to reduce nutrient and water usage in greenhouse floriculture operations, but their utility could be further enhanced by the optimization of nutrient delivery. Recent research with chrysanthemum combined a moderate rate of nitrogen (N) or sulphur (S) supply during vegetative growth with the removal of the entire suite of nutrients during reproductive growth. The delivery of N and S, respectively, was reduced by approximately 75 and 87.5 per cent over the crop cycle, compared to industry standards, and without adverse effects on plant and flower quality.
ods offer a novel delivery strategy for efficiently reducing the Pi nutrition of chrysanthemum.
Disbudded, potted chrysanthemums were grown in a peat-perlite mix under greenhouse conditions using two cultivars, ‘Olympia’ and ‘Covington,’ and four different Pi treatment rates, each replicated in four different areas of the greenhouse. One treatment was similar to the industry standard, where 80 ppm Pi was supplied as a complete nutrient solution over both veg-
Chrysanthemums were tested using different phosphorus regimens.
Recently, we tested two methods for reducing Pi delivery to subirrigated, potted, disbudded chrysanthemums: (1) Pi removal during the reproductive growth stage; and (2) reduction of Pi rate during the vegetative growth stage. All the Pi regimens tested produced market quality plants, even when Pi delivered over the crop cycle was substantially less than typical industry recommendations. Together, these two meth-
etative and reproductive growth stages (labelled as 80VR). The three remaining experimental treatments, 80, 60 and 40 ppm Pi, were supplied in an otherwise complete nutrient solution until bud crack (i.e., the vegetative stage only), and then replaced with deionized water thereafter (labelled as 80V, 60V and 40V, respectively). Some plants were harvested at bud crack (i.e., ear-
ly flowering) and again when the flowers were fully expanded (i.e., late flowering, 8 weeks after short days were imposed to induce flowering), and assessed for visual quality, plant characteristics, and tissue-P in various plant parts.
Being distinct cultivars, the morphological characteristics (i.e., shoot length, bloom diameter and dry mass yields) differed between ‘Olympia’ and ‘Covington’. However, neither cultivar was affected
by removing Pi during the reproductive phase and/or reducing Pi during the vegetative stage. Market quality flowers were produced without any decrease in bloom diameter or visible symptoms of P deficiency on either leaves or flowers (Fig. 1), even when given the lowest Pi treatment of 40 ppm Pi during the vegetative stage, and zero Pi during the reproductive stage (40V). Notably, ‘Olympia’ had much lower levels of leaf-P than ‘Covington’ across all Pi treatments, but the acquisition of P was similar in 40V ‘Olympia’ and 60V
Hoogendoorn’s next generation iSii monitors and controls all climate, irrigation and energy equipment in all types of greenhouses. The iSii is equipped with advanced controls that work according to the principles of Plant Empowerment, which resulted from Next Generation Growing (NGG) research. This way light, temperature, humidity and CO2 are aligned with each other for a maximum photosynthesis. In addition, to prevent water stress, irrigation is driven by the evaporation energy and water balance of the crop. With the iSii process computer, you set the base for high quality production.
‘Covington.’ Based on literature values for tissue-P in a diagnostic leaf during early flowering, these findings indicate that none of the Pi regimens limited plant development and growth, and that ‘Olympia’ utilized the available Pi more efficiently than ‘Covington’ over the crop cycle.
Phosphorus can be stored, primarily in the leaves and stems, during the vegetative stage, then drawn from during the
The primary strategy for improving P use efficiency in the plant was increased uptake efficiency.
reproductive stage when root uptake is relatively poor to satisfy some of the P demands for flower and seed development. P deficiency typically promotes the movement of Pi into and through the roots, as well as the release of P stored either as Pi or organic forms, for metabolism and/or transport to other areas of the plant as needed.
To better understand how chrysanthemums were able to compensate for the different Pi treatments, we estimated the actual Pi inputs delivered with each treatment in the nutrient solution over the crop cycle, and tracked three measures of P use in the plant:
1. Input-based P-use efficiency – A measure of how efficiently the plant used up the applied P (PUEi = shoot dry weight divided by weight of Pi input);
2. Input-based P-uptake efficiency – A measure of how efficiently the plant took up the applied P through its roots (PUpEi = shoot P content divided by weight of Pi input);
3. Content-based P-use efficiency: A measure of how efficiently the plant used its stored P in the shoots (PUEc = shoot dry weight divided by shoot P content).
All measures increased in both cultivars with decreasing Pi delivery, indicating that the plant compensated for lower P applied using all three methods above. The primary strategy for improving P use
Hartmann and Kester’s Plant Propagation remains the field’s most complete and up-to-date guide to the principles and practices of plant propagation. Using color figures throughout, the text pairs chapters on horticultural science with commercial techniques for plant propagation.
There is an introduction to the industry and basic plant biology, it then dives into more complex technical concepts, ranging from seed and vegetative propagation, to propagation techniques for specific fruits, nuts, and crops for the greenhouse and nursery.
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Fig. 1. Market quality flowers were produced without any visible symptoms of P deficiency on either leaves or flowers in ‘Olympia’ and ‘Covington.’ Treatments: 80VR received 80 ppm Pi over the vegetative and reproductive stages. 80V, 60V and 40V received 80, 60 and 40 ppm Pi, respectively, over the vegetative stage only.
efficiency in the chrysanthemum plant was increased uptake efficiency (Fig. 2). This could be explained by stimulation of multiple transport proteins that mediate the movement of Pi from the soil into and through the root, driven by a reduction in Pi availability. These findings confirm that ‘Olympia’ has greater internal utilization efficiency than ‘Covington’ over the crop cycle, especially when one considers that 40V ‘Olympia’ and 60V ‘Covington’ acquired the same amount of Pi.
From the differences in biomass yields, tissue-P concentrations, and content-based P-use efficiency with constant Pi acquisition, it is clear that ‘Olympia’ has greater P-utilization efficiency than ‘Covington’ when Pi availability is non-limiting. Other research has established that stored organic-P, and to a lesser extent Pi, are more important sources of P for flower development in ‘Covington’ than in ‘Olympia’, likely due to the higher tissue-P levels at flower emergence. Despite their differences, both cultivars produced market quality plants
and flowers, even when Pi delivery over the crop cycle was reduced to approximately 25 per cent of typical industry recommendations.
The success of our modified subirrigation practice (i.e., using moderate levels of a specific nutrient during vegetative growth combined with removal of all nutrients during reproductive growth) was previously demonstrated with N and S. We are continuing the study of the remaining macronutrients (i.e., potassium, calcium and magnesium), as well as the micronutrients (i.e., zinc, copper, iron, manganese, boron and molybdenum), in order to develop a complete, optimized nutrient regimen, which will then be validated in a commercial setting. Since there does not appear to be cultivar-specific responses in chrysanthemum to the modified management practice, it should be readily adoptable by growers. In the longer term, the modified practice could be applied to other agriculturally important, indoor-grown crops.
Acknowledgements: This research was funded by the Canadian Ornamental Horti-
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Fig. 2. Impact of Pi treatment on inputbased phosphorus uptake efficiency (PUpEi = mg shoot P content/mg Pi input) of ‘Olympia’ and ‘Covington’ chrysanthemums. 80VR received 80 ppm Pi over the vegetative and reproductive stages, whereas 80V, 60V and 40V received 80, 60 and 40 ppm Pi, respectively, over the vegetative stage only.
culture Alliance and the Ontario Ministry of Agriculture, Food and Rural Affairs through the OMAFRA-University of Guelph partnership. Thanks to Berger for providing the growing medium.
For more details, see the article,“Strategic timing and rate of phosphorus fertilization improves phosphorus use efficiency in two contrasting cultivars of subirrigated greenhouse-grown chrysanthemum”, which is published in the Canadian Journal of Plant Science (DOI: 10.1139/CJPS-20190173).
For more background, see the articles, “Moving towards low-input floricultural operations”, and “Managing sulphur nutrition of sub-irrigated greenhouse-grown chrysanthemum”, which are, respectively, published in the December 2018 and July 2019 issues of Greenhouse Canada magazine.
Barry Shelp, William Sutton and Edward Flaherty are Professor Emeritus, graduate student and research technician, respectively, in the Department of Plant Agriculture at the University of Guelph. For more information, please contact Dr. Shelp at 518-824-4120 ext. 53089, or bshelp@uoguelph.ca.
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Experts talk pain points and automation solutions for pest management in the greenhouse.
Pests are perennial problems in the greenhouse, but as technology continues to evolve, so do various ways of eradicating pests. Charlie McKenzie, CropWalk’s co-founder and director of partnerships, and Allison Kopf, CEO of Artemis, talk about today’s biggest pain points in pest management, costly mistakes they’ve encountered, and how innovative technology fits into future solutions.
What are the biggest pest management pain points today for commercial greenhouse operations?
CM: First, it’s a challenge to keep up with ever-evolving regulations and new products. There are chemicals today—especially in Canada—that growers can’t use on food and cannabis crops, or even ornamentals. While consumer safety is paramount, regulations have eliminated the use of many pest control tools, which has left growers with fewer options.
Second, is an increased resistance amongst pests to chemicals. Growers have to apply chemicals more regularly, and in turn, pests become resistant. It’s a vicious cycle. Growers apply chemicals thinking they’re beneficial, and they’re actually having an opposite effect.
Third, there’s a massive shift in the general practice of pest management. Regulations and pest resistance have rendered the traditional spray-and-pray methodology ineffective or illegal. Consequently, growers must focus more on proactive preventive measures and relearn how to scout and monitor for pests before a major problem occurs.
What are the top one or two considerations any grower should make when tightening their pest management protocol?
CM: The first step is for growers to understand the available tools including biocontrols. Some growers of higher margin crops like cannabis can use biocontrols at scale. But ornamental, leafy greens, and fruit and vegetable growers often must integrate traditional chemistry and biocontrols to stay cost-effective. Understanding all available tools and how they interact will give growers a leg up.
The second step is to establish an objective scouting and monitoring program. Knowing what exists in a crop and being able to look at those trends regularly crop-over-crop, year-overyear is important. If a grower uses biocontrol or a chemical on aphids, they might kill most in that initial sweep, but you can’t stop there. Growers need to check on a weekly basis to gauge how effective the control method performs over time.
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What are some common and most costly mistakes growers make when trying to eradicate pests from their production?
CM: One of the biggest mistakes is when growers integrate biocontrols into a program, but treat perishable beneficial insects as they would a chemical. Growers might order biocontrols once a month, but that’s not frequent enough for perishable biocontrols, which often require weekly shipments to remain effective.
Growers also have to ensure the biocontrol they ordered arrives alive. Many growers unknowingly apply dead or low quality beneficial insects to their crop. They receive a shipment, but skip quality assurance to verify the bugs arrived alive. Growers spend physical labour to apply dead bugs to crops, which is a massive and costly mistake.
Another mistake goes back to the regulatory issue. Growers that don’t pay attention to what’s on a label or regulations risk getting hit with a fine or a product rejection from a store. The produce safety industry—especially cannabis—is changing so fast that things go on and off the accepted list pretty quickly. Growers not in the know and up-to-speed could be applying something to a crop that’s going to leave it void of any value.
How does pest management fit into the larger picture of cultivation management and reducing risk to greenhouse operations from both a profitability and compliance standpoint?
CM: Pest management is probably the one variable that’s impossible for growers to control. It’s possible to figure the proper irrigation strategy down to the milliliter. Growers can make decisions about that strategy by controlling for variables like
the weather, time of year, and crop age.
But you can’t control every variable with pest management. You can’t control how the bad bugs enter your greenhouse. If you have a completely closed system and nothing can get in, that’s one thing. But most operations can’t say with certainty that they don’t have aphids or spider mites in their crop. You can’t yank a water valve and turn off pests; they’re a variable that’s uncontrollable. You have to look at it on a weekly basis, and it’s not going to be the same year-over-year or even crop-over-crop.
Knowing that pests will throw curve balls at you and having a contingency plan are what’s going to possibly save you from reducing profitability on the compliance side. Many crops have restrictions on what can be on the plant at time of sale. From my experience in the ornamentals business, I would ship a truck that would have certain pests on it and they would send it back. We wouldn’t get credited for that money and it would be a total loss. Growers need to hedge their bets from the beginning by having a pest management plan in place, which could prevent major potential financial losses.
What are some common links between insects that cause damage both by feeding on plants, but also by spreading diseases, and how can both be controlled by proactive insect control?
CM: Certain insects like fungus gnats can open up the roots to a challenge in soilborne diseases. They pierce the surface of the roots while feeding, and then in overly moist conditions, this allows pythium to develop. Thrips and aphids both transmit viruses. Having them in your crop might mean you are at risk of a virus being transmitted. It can certainly be a cause-and-effect relationship between insects and disease.
Controlling aphids, thrips, and fungus gnats up front is not only going to prevent pest damage that’s either aesthetically displeasing or that reduces yields, but it also might prevent a virus or pathogen that would be transmitted by those pests. Piercing and sucking mouthparts on insects can give the insect the ability to be a vector and transmit some sort of pathogen. Preemptive pest control can alleviate some of these potential issues.
What are some key practices that can minimize the risk and/or buildup of pest infestations?
AK: Controlling pests in greenhouses
and other controlled environments is a critical component of a larger cultivation management strategy aimed at reducing operational and financial risk, as well as maintaining regulatory compliance. While crop damage and contamination can always occur post-harvest, common pests including thrips, aphids, spider mites and various molds and diseases infest and attack plants during cultivation between seed and harvest.
Many growers have widely adopted integrated pest management (IPM)
as a system of best practices to fight pests. IPM employs a variety of cultural, chemical, and biological controls during cultivation to minimize overall risk and prevent any buildup of infestations.
Simple, proactive tactics such as facility maintenance and sanitation can play a huge role in preventing pests or pest buildup. For instance, one of the biggest issues in pest management is cross contamination. Moving plants from cultivation zones to harvesting zones can promote the spread of disease and pests throughout the
greenhouse. Some of this can be mitigated before operations start, by designing the facility with separate harvest and vegetative rooms where plants are moved in a single direction, rather than back and forth. This isolates pests and prevents them from contaminating entire batches.
What is the role that technology, data, and automation can play in early detection and diagnosis?
AK: Pest control professionals are beginning to adopt mobile devices to get real-time data about the nature and severity of pest problems. They can host the data online or in the cloud for facility managers, laborers, and pest control professionals to easily access and evaluate. This allows the facility to identify issues quickly and be agile in their response.
As an early detection tool, the use of this automated technology and real-time data allows facility managers to deploy labour more strategically. Imagine you have 300 acres with people physically walking around counting bugs on sticky traps. That is wildly inefficient and wastes money and labour. These devices free up time that would otherwise be spent on the painful process of manually patrolling crops, but they also allow facility managers to identify precisely where labour needs to be deployed to fight early pest infestations or disease.
Furthermore, real-time data can allow growers to take preventative actions to avoid infestations and disease before they even develop. With ever increasing measurements of new integrated data points (e.g. being able to measure the presence of harmful airborne spores) growers can not only make decisions more quickly, but they can make the right decisions.
What are some innovative technologies and solutions on the market today for pest management?
AK: Koppert Biological Systems is a leading pest management company that offers a complete program of products and services for IPM. It provides a mobile app that can take pictures of sticky cards and identify bug count and type. One of their solutions is an integrated mobile iPM (intelligent pest management) app and dashboard for more efficient scouting, which is a significant part of pest management. The app uses GPS outdoors for mapping, and real time data from the field. Showing what pests exist and where saves time on scouting, allowing for fast and targeted
Another innovative company in the pest control space is Scanit Technologies, an Artemis partner. Scanit uses sensors to detect airborne particles and spores. These are analyzed against common spores known to be dangerous to particular crops in the greenhouse. If hazardous spores are identified, Scanit relays this information to growers, who can then act before a fungus or disease problem even fully materializes.
Why is having a Cultivation Management Platform (CMP) a critical part of pest management, and what gaps does it cover that an existing ERP doesn’t?
“...growers can not only make decisions more quickly, but they can make the right decisions.”
AK: ERPs are great at aligning horizontal functions like payroll, billing, inventory tracking, logistics, etc. The downside is that they are expensive, difficult to implement, and most importantly, not industry-specific. This is critical when it comes to pest management, because a CMP allows growers to sync and track all of their pest control data along every point from seed-to-harvest.
Once a grower has identified the source or cause of a pest-related problem, a CMP provides full traceability, allowing growers to go through their data and understand what specific action they need to take to eliminate the problem. With a CMP, growers can truly manage risk and compliance by tracking precisely where a problem arose and understand how far it spread. It doesn’t matter what you grow or how you grow it, all crops are vulnerable to pests, and an ERP can’t help manage this risk to product and profits.
On the labour side, greenhouse facility managers can even track what employees were on site and in which areas where the disease or pests originated or spread. Rather than losing an entire batch due to a small, isolated pest issue or disease that has gone untracked, a CMP can show growers precisely what plants need to be destroyed and which ones don’t, saving growers huge amounts of time and money.
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GARY JONES | Gary.Jones@kpu.ca
The figures are in. 256.6mm for January 2020.1 Fifth most rainfall on record. A ‘normal’ January average is 158 mm, and Vancouver saw 22 consecutive days of rain this year (26 days for the month). OK. OK. You’re right – we don’t have to shovel it, so we should stop whining. But go tell that to the folks with flooded homes, wrecked cars and those stuck at Sasquatch Mountain Resort. It seems like an odd month to consider the theme of irrigation.
With this year’s Pacific Ag Show, the LMHIA Short Course offered almost a hundred presentations (98 actually), with seven specifically on the topic of water or irrigation. A full morning session on ‘Agriculture Water Management’ included subjects such as ‘Variable Rate Irrigation Improvements’, and ‘Salinity Monitoring in Delta’. Talks in the separate blueberry session discussed ‘Using Drones to Manage Irrigation in Blueberries’, and ‘Achieving Optimal Yields and Fruit Quality Through Precise Irrigation’.
Sadly, I couldn’t get to these talks, but I did drop in on several sessions across diverse horticultural fields including hops, organics and mushrooms. No matter your interests, horticulture, in particular as showcased at events like this, always has something to offer. The fascinating multi-disciplinary nature of horticulture struck me once again.
irrigation (or deficient drainage system) will increase the likelihood of contamination by and spread of water-borne diseases. No need to incur unnecessary plant losses or use chemical fungicide treatments if simply improving irrigation efficiency can have the same benefits. Doing all of these ‘Good Agricultural Practices’ will also likely lead to improved profits.
• A project by Mirella Aoun and colleagues found that reducing irrigation in organic cranberry fields has the potential to promote plant establishment and simultaneously reduce weed pressure.2 Probably similar techniques applied to field nursery crops, or soil-grown greenhouse crops, have likewise benefits.
• Following on from that, such a benefit would clearly impact the bottom line with reduced labour. And we all know the issues with securing labour for our industry.
• Also from the world of organic crop research, a project by Liette Vasseur and colleagues is investigating combinations of cover crops, rootstocks and irrigation techniques to enhance soil health and grape quality.3 The project is also looking at how such techniques can help build resilience into such a crop system. Greenhouse tomato growers are familiar with the effects of irrigation on fruit quality (especially cherry tomatoes), but are there more wide-reaching benefits we have not yet considered?
...see if there is anything you can learn from other sectors...
Often times in the greenhouse sector we look at the details of irrigation such as when, how much, what time of day, specifics of EC, pH, and nutrient concentrations. We sometimes don’t appreciate the secondary benefits that come with good irrigation practices, some of which were the focus of LMHIA talks. These include:
• Saving water. Obvious, I know, and it hardly seems worth bothering about in BC in January, but come June, July…. Right – it’s a different story then. And if the water includes fertilizer, then there are associated savings in fertilizer costs.
• Should any excess irrigation water run off to nearby creeks or other water courses, then reducing waste water will also reduce potential pollution. Most of us are aware of legislation aimed at preventing waste water run-off, so I hope this is not a surprise. But there may be unseen leaks in pipelines and faults in any runoff prevention structures, so it’s always good to do an audit of the systems every now and then.
• Another somewhat obvious one, is that excess
• We all know the dangers of irrigation lines dripping onto pavers or concrete paths, and how algae can quickly build up. Inevitably, this brings an increased risk of falls, worker injury and possible time off work. Such issues are easily avoidable with a regular eye on fixing deficient irrigation lines. And who knows, attention to this may even reduce your insurance premiums. So stop being a drip. Have a walk around your workplace, and see if there is anything you can learn from other sectors like organics, mushrooms and hops.
1 www.Vancouver.weatherstats.ca/
2 White, J, et al, (Eds) (2018) Organic Science Canada, Vol. 1. Organic Fed of Canada, Montreal, pp. 46.
3 https://www.dal.ca/faculty/agriculture/oacc/en-home/organicscience-cluster/OSCIII/horticulture-/activity-15.html
Gary Jones is a faculty member of the School of Horticulture at Kwantlen Polytechnic University, Langley, BC. He sits on several industry committees and welcomes comments at Gary.Jones@kpu.ca.
