Progressive Crop Consultant - July/August 2019 by JCS Marketing, Inc.

July/August 2019 Mitigating Pesticides and Sediment in Tail Water using Polyacrylamide (PAM) Do Liquid Digestates, By-Products of Bioenergy Production, have Nematode-Suppressive Potential? Management Practices to Improve Soil Function Neofabraea Leaf and Twig Lesions, a New Disease of Super-High-Density Olive Trees

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PUBLICATION

July /August 2019

PUBLISHER: Jason Scott Email: jason@jcsmarketinginc.com EDITOR: Kathy Coatney ASSOCIATE EDITOR: Cecilia Parsons Email: article@jcsmarketinginc.com PRODUCTION: design@jcsmarketinginc.com Phone: 559.352.4456 Fax: 559.472.3113 Web: www.progressivecrop.com

IN THIS ISSUE

4 12 16 22 26 36

Mitigating Pesticides and Sediment in Tail Water using Polyacrylamide (PAM) Selective Forces That Act on Weeds and How They can Alter Plant Populations and Communities

CONTRIBUTING WRITERS & INDUSTRY SUPPORT

Do Liquid Digestates, By-Products of Bioenergy Production, have NematodeSuppressive Potential?

Zhixuan Qin

Department of Agricultural and Biological Engineering, UC Davis

UC Cooperative Extension Montery County

Michael Cahn UC Cooperative Extension Monterey County

UCCE Agronomy and Weed Science Advisor, Merced and Madera Counties

David Chambers

Florent Trouillas

UC Cooperative Extension Monterey County

Cooperative Extension Assistant Specialist in Plant Pathology, University of California

Caroline Eberlein

Management Practices to Improve Soil Function

Iron Deficiency in Fruit and Nut Crops in California

Abdelhossein Adelati

Department of Nematology, UC Riverside, Parlier, California Andreas Westphal Department of Nematology, Matthew Fidelibus UC Riverside, Parlier, Extension Specialist, California Department of Viticulture and Enology, UC Davis Mohammad Yaghmour Area Orchard Systems Phoebe Gordon Advisor, Kern County Area Orchard Systems Advisor, Merced County Ruihong Zhang Department of Agricultural Sarah Light and Biological Engineering, Agronomy Advisor, Sutter, UC Davis Yuba, and Colusa Counties

UC COOPERATIVE EXTENSION ADVISORY BOARD Kevin Day

Magnesium Deficiency in Grapes

Emily J. Symmes

County Director and UCCE IPM Advisor, UCCE Pomology Farm Sacramento Valley Advisor, Tulare/Kings County

Steven T. Koike,

Kris Tollerup

Director, TriCal Diagnostics

Neofabraea Leaf and Twig Lesions, a New Disease of Super-HighDensity Olive Trees

Lynn Sosnoskie

UCCE Integrated Pest Management Advisor, Parlier, CA

The articles, research, industry updates, company profiles, and advertisements in this publication are the professional opinions of writers and advertisers. Progressive Crop Consultant does not assume any responsibility for the opinions given in the publication.

July /August 2019

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Mitigating Pesticides and Sediment in Tail Water using

Polyacrylamide (PAM)

BY MICHAEL CAHN | UC Cooperative Extension Monterey County ZHIXUAN QIN | UC Cooperative Extension Monterey County DAVID CHAMBERS | UC Cooperative Extension Monterey County

Progressive Crop Consultant

July /August 2019

HERBICIDE EC

FORORGANICPROD

“By 1999, almost 1 million acres of land

were annually treated with PAM in the northwest of the United States.

“

prinkler and flood irrigation often generate runoff that transports sediment from agricultural fields to downstream rivers, lakes, and estuaries. Additionally, some classes of pesticides, such as pyrethroids, bind to the suspended sediments in tail water which can cause toxicity to aquatic organisms in these receiving waters. Currently numerous rivers and creeks in California are considered impaired by pesticides and sediment transported with drainage from agricultural land. As water quality regulations become stricter, growers will need to implement practices on their farms that treat potential pollutants in runoff.

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Tail water can be a particularly challenging water quality problem on the central coast of California where overhead sprinklers are widely used for vegetable production. Sprinklers can contribute to high concentrations of suspended sediment in tail water because the force of the falling water droplets erode soil aggregates and allow fine particles to be carried with runoff water. Research that we have conducted on the central coast has shown that adding a low concentration of polyacrylamide to irrigation water can dramatically reduce sediment loads and sediment-bound pesticides in agricultural tail water (Figure 1, see page 6). Across a range of soil types, polyacrylamide treatment reduced sediment concentration in runoff by more than 90 percent on average. On some highly erosive soils polyacrylamide reduced sediment concentration in sprinkler induced runoff by more than 98 percent. Total phosphorus and nitrogen concentrations in sprinkler runoff were also reduced by 40 percent to 70 percent using polyacrylamide.

Despite dramatic improvements in water quality, polyacrylamide, also called PAM, has been slow to be adopted as a management practice on the central coast and in much of California. One reason may be because of misunderstandings about how to most effectively use PAM for treating runoff, especially for sprinkler irrigation. Another reason is that several physical properties of polyacrylamide make it challenging for handling and applying to fields.

Continued on Page 6

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Working with PAM PAM can be very difficult to use if it is not handled correctly. Wet PAM is very slippery, and because it solubilizes slowly in water, PAM spills should be cleaned up with a dry absorbent rather than washing it with water. Although it is not toxic to humans, some precautions should be taken when handling PAM: Use gloves to avoid irritation to skin. Goggles will prevent eye exposure. Also, a dust mask is recommended when pouring or handling granular or powder forms of PAM to avoid inhalation.

One rule of thumb to keep in mind is that it is much easier to add water to PAM than to add PAM to water. Dry PAM rapidly Figure 1: Runoff from overhead sprinkler water untreated (left). Treated with 5 ppm PAM (right). absorbs water, increasing its original volume many times to become a slimy, gooey substance. Dissolving dry PAM in water can be challenging. Because PAM is a very large molecule it does not dissolve readily into water and requires Continued from Page 5 many hours of agitation to dissolve. It will often stick to the side of a tank when being mixed. Also, mixing up concentrations greater than 0.15 percent in water is nearly Brief background on PAM impossible because the solution becomes very viscous and Polyacrylamide is a simple polymer molecule made of difficult to agitate. Some manufacturers sell effervescent PAM tablets which aids dissolution in water, but still only carbon, nitrogen, and oxygen. Various forms of PAM exist, relatively dilute solutions can be mixed up. but the type used to stabilize soil and prevent erosion is a very large, mostly negatively charged molecule (12-15 For these reasons it easiest to use liquid PAM products megagrams per mole). Agricultural PAM is commercially that have been emulsified with a carrier such as mineral available in dry powder (granular), emulsified liquid, and oil or humectants, or work with dry PAM products, dry tablet forms, and costs as little as $4 to $6 per pound of such as granular PAM or PAM in a tablet form. The active ingredient depending on the formulation, supplier, emulsified liquid products generally have active ingredient and cost of the raw materials used for manufacturing PAM concentrations ranging from 25 to 50 percent. (i.e. natural gas). PAM is used for many nonagricultural purposes such as a flocculant for waste and potable water Application Methods treatment, processing and washing of fruits and vegetables, clarification of juices, and paper production. It is also a For applications in furrow systems dry or liquid product component of makeup. can be added to water flowing in a head ditch or main line (if gated pipe is used) at a rate to achieve a 2.5 to 10 ppm Use of PAM for Irrigation (parts per million) concentration. Automated equipment can be used to spoon feed granular PAM into flowing and Erosion Control canal water. The application can be made continuously Because PAM is a very long, linear molecule it easily binds during the irrigation or until the water advances almost to to soil aggregates, thereby preventing soil erosion during the end of the furrows. An alternate application method, irrigation events. Beginning in the early 1990’s numerous called the “patch method” involves spreading granular studies demonstrated that low application rates of PAM (1 PAM to the first 3 to 5 feet of each furrow. The granular to 2 lb/acre) reduced runoff and improved water quality PAM slowly dissolves as water flows down the furrows. A in furrow systems by stabilizing the aggregate structure of similar strategy is to add a PAM tablet at the beginning of soil, improving infiltration, and flocculating out suspended each furrow. Applications into sprinkler systems require sediments from irrigation tail water. Most of the research specialized equipment for injecting either liquid PAM or and demonstrations of PAM were conducted in furrow dry PAM into pressurized pipe which will be discussed in system on very erodible soils in Idaho and Washington more detail later. states.. By 1999, almost 1 million acres of land were annually treated with PAM in the northwest of the United Environmental and Food Safety States. Additionally, growers in the San Joaquin Valley and Only PAM products labeled for application to food crops the Bakersfield areas of California used PAM to reduce soil should be used in agriculture. Also, the buyer/processor/ erosion under furrow and flood irrigation. 6

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July /August 2019

Federal Environmental Protection Agency (EPA) requires that PAM sold for agricultural uses contain less than 0.05 percent acrylamide monomer. In soil, PAM degrades rapidly by physical, chemical, biological, and photochemical processes, but it does not decompose into the acrylamide monomer. A previous study of the movement of PAM from agricultural fields showed that less than three percent of the applied product remained in the runoff leaving the field. The remaining PAM in the tail water was almost completely removed through adsorption to suspended sediments as the water flowed a distance of 300 to 1000 ft. in the tail water ditch. Figure 2: Trailer outfitted for injecting liquid PAM into the main line of an irrigation system using an auger metering pump.

shipper of the produce should be informed that PAM is being applied to the crop, especially if the application is made near harvest. Agricultural PAM used for soil erosion is not toxic to mammals. Environmental studies of anionic (negatively charged) PAM have not shown any detriment

to fish, algae, and aquatic invertebrates such as Ceriodaphnia dubia, and Hyalella azteca. Polyacrylamide is sometimes confused with acrylamide monomer, a precursor in the manufacturing of PAM. Acrylamide monomer, a potent neurotoxin, has a high, acute toxicity in mammals. The

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One concern with using emulsified liquid PAM is that the mineral oil carrier can have toxicity to downstream aquatic invertebrates. However, toxicity from the mineral oil can be avoided by using PAM formulations with either high concentrations of PAM (>50 percent active ingredient) or with nonoil carriers such as humectants.

Optimizing PAM for Sprinklers Although many research studies have evaluated the efficacy of PAM in furrow systems, fewer studies have evaluated the use of PAM with sprinklers. Applications of PAM made before irrigating with sprinklers, such as by spraying PAM solution or broadcasting dry product on the surface of the soil were far less effective than continuously injecting PAM at a low rate into the irrigation water. Injecting PAM only at the beginning of an irrigation was also less effective in controlling sediment in runoff than a continuous application at a low concentration during the entire irrigation. Our studies on the central coast showed that injecting PAM to achieve a 5 ppm concentration in the irrigation water provided the highest reduction in sediment, nutrients, and pesticides in the tail water using the least amount of product. In some fields 2.5 ppm PAM provided equal efficacy for control of suspended sediments as 5 ppm PAM. Treatment with PAM should be started with the first irrigation after planting and continue during the following two to three irrigations. PAM should be reapplied when sprinkler irrigating after the field has been cultivated. Product can be saved in

Continued on Page 8 July /August 2019

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Figure 3: Prototype dry PAM applicator for pressurized irrigation systems (left) and PAM cartridge that inserts into the applicator (right).

Continued from Page 7 fields where very little runoff occurs during the first few hours of an irrigation by making an initial application for the first half hour and then applying product again when runoff becomes significant.

Injecting PAM into Pressurized Irrigation Systems The chemical characteristics of PAM that make it so effective as a flocculant, also make it difficult to inject into pressurized irrigation systems. Liquid PAM solutions are viscous and will clog chemigation equipment with valves such as diaphragm and piston pumps, as well as venturi injectors. Also, because the desired PAM concentration in the irrigation water is low, injection rates as low as one to three ounces per minute are needed to treat 10 to 15-acre fields. Most small, gas-powered centrifugal pumps usually cannot be easily calibrated to inject at these low rates. Peristaltic pumps can be adjusted to inject slowly but often are not designed to operate under high pressures that are common in sprinkler main lines. The best type of pump that we have identified for injecting liquid PAM is an auger pump (Figure 2, see page 6) which has no valves and can inject viscous solutions at very low rates. These pumps also maintain a consistent injection rate at pressures as high as 100 psi (pounds per square inch). Although liquid formulations of PAM are the best option for pressurized irrigation systems, we are currently exploring methods of injecting dry PAM into pressurized sprinkler systems. The advantage of dry PAM is that it is generally cheaper than liquid products and the possibility of introducing toxicity from the inactive emulsifying 8

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July /August 2019

ingredients in the liquid products is eliminated. Another advantage of this approach is that it may require less labor since no pump must be calibrated and managed during an irrigation. The dry PAM applicator is loaded with cartridges containing either granular or tablet forms of PAM (Figure 3). A portion of the water from the main line is diverted through the applicator chambers and then added back to the main water stream. Although the PAM concentration is lower than can be achieved with liquid PAM, preliminary tests have shown that as much as 90 percent of the suspended sediments can be eliminated in the runoff (Figure 4, see page 10). Further studies during the upcoming season will evaluate the practicality of use this applicator in commercial fields.

Other Potential Benefits of PAM In addition to water quality benefits, we have observed or measured agronomic benefits from the use of PAM. Because PAM stabilizes soil aggregates, soil is less likely to crust under the impact of sprinkler droplets, which improves infiltration and decreases the volume of runoff. In one field trial, PAM reduced runoff from four successive sprinkler irrigations from 4000 gallons per acre to less than 1500 gallons per acre. Less crusting of the soil may also improve germination of small seeded vegetables such as lettuce. In one of four replicated field trials conducted in commercial lettuce fields, we were able to measure an increase in yield and plant weight with the use of PAM. This yield increase may have been a result of better penetration of water or because the seed emerged earlier than in the non-treated plots. Although we have not conducted long-term studies, anecdotal reports from growers who applied PAM to their fields over successive years were that soil structure was improved by keeping the fine particles in place.

Continued on Page 10

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July /August 2019

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Figure 4: Samples of field runoff from irrigation water treated using the dry PAM applicator (left) and untreated (right).

Continued from Page 8 An additional benefit of PAM is the savings associated with less frequent cleaning out of sediment that clogs ditches and fills retention ponds during the irrigation season. Often once or twice per year growers on the east side of the Salinas valley who farm on soils prone to crusting and runoff must schedule a backhoe and crew to remove sediment from ditches and ponds and redistribute the material in their fields. To reduce costs with using PAM, growers also can receive costshare payments under the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Environmental Quality Incentive Program) (EQIP). In summary here are a few key concepts on using PAM for controlling sediment in runoff: • Polyacrylamide is a long linear molecule that binds to soil and can flocculate suspended sediments in water. • PAM does not readily solubilize in 10

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water and increases the viscosity of water (thickens). • Concentrations of 2.5 to 5 ppm PAM in irrigation water are ideal for optimizing erosion control benefits under sprinkler and furrow irrigation. • For agricultural purposes only use anionic PAM products for erosion control and labeled for use on food crops. • Small amounts of granular PAM can be applied to the beginning of furrows before flood irrigating (1 to 3 lbs/acre).

• PAM itself is not toxic, but the mineral oil in some liquid PAM products can be toxic to aquatic organisms. • A prototype applicator is being developed to inject dry PAM into pressurized sprinkler systems, although it is not yet commercially available. Further information on using polyacrylamide is available on the UC Cooperative Extension Website for Monterey County (http://cemonterey. ucanr.edu/Custom_Program567/ Polyacrylamide_PAM/)

• For sprinklers PAM needs to be injected into the irrigation water during the entire irrigation event. • Applying PAM to the soil before sprinkle irrigating or only at the beginning of an irrigation will not maximize control of sediment in runoff. • PAM should be applied during the first three to four irrigations after planting or transplanting and when irrigating after soil cultivation. • Auger pumps are ideal for metering liquid PAM products into pressurized sprinkler water.

July /August 2019

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SELECTIVE FORCES THAT ACT ON WEEDS and How They Can Alter Plant Populations and Communities Figure 1. All photos courtesy of Lynn Sosnoskie.

BY LYNN SOSNOSKIE | UCCE Agronomy and Weed Science Advisor, Merced and Madera Counties

eeds are problematic in crops, primarily because they compete with commodities for water, light, and nutrients, which can result in yield loss. Weeds can also impact crops, indirectly, by serving as alternate hosts for insects and pathogens (Del Pozo-Valdivia 2019; Petit et al. 2011), providing habitat for vertebrate pests (White et al. 1998), or by impeding harvest operations (Morgan et al. 2001; Smith et al. 2000), among many other effects.

Resistant Weeds Consequently, growers employ a variety of control strategies, including the application of herbicides, to manage unwanted vegetation in their production systems. Although herbicides can be extremely effective, weeds may escape chemical control for a variety of reasons, including the evolution of herbicide resistance. Currently, there are 500 confirmed cases (species x site of action) of herbicide resistance, worldwide (Heap 2019). With respect to the United States, 164 unique instances of resistance have been documented. Most resistances (52 cases) are to the acetolactate synthase (ALS) inhibitors followed by the photosystem II (PS II) inhibitors (26 cases), 5-enol-pyruvyl-shikimate-3phosphate synthase (EPSPS) inhibitors (17 cases), and the acetyl-CoA carboxylase (ACCase) inhibitors (15 cases) (Heap 2019). Examples of active ingredients for these sites of action would be rimsulfuron (ALS-inhibitor), atrazine (PS II-inhibitor, glyphosate 12

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(EPSPS-inhibitor), and sethoxydim (ACCase-inhibitor), respectively.

Herbicide Resistance Herbicide resistance is an evolutionary process. Herbicides do not directly cause the mutations that lead to herbicide resistance, rather their repeated use over space and time ‘selects’ for the genetic mutations that result in reduced herbicide efficacy. In short, the genetic mutations that confer herbicide resistance are already present before the herbicide is applied. The herbicide treatment eliminates all the weeds that do not contain the mutated gene (i.e. the susceptible plants); if no further intervention is undertaken, the resistant survivors will continue to grow, flower, and set seed, which will be added to the soil seedbank. Over time, the resistant trait becomes dominant in the population as susceptible individuals die out without successfully reproducing (Figure 1) (Hanson et al. 2013).

Adaptations to Weed Control Herbicides are not, however, the only selective forces that can alter the structure of weed populations and communities. Any weed management or crop production practice can select for weed species that are adapted to the resulting environment. For example, repeated and consistent mowing (Pirchio et al. 2018) can favor the development of species that are naturally prostrate or spreading in habit, like clovers (Trifolium spp.) (Figure 2,

July /August 2019

see page 14). The use of drip-irrigation in processing tomatoes can lower the numbers of annual weeds that emerge and compete with the crop (likely due to reduced surface wetting that stimulates germination) while facilitating the establishment of field bindweed (Convolvulus arvensis), a deep-rooted and drought-tolerant perennial weed (Shrestha et al. 2007; Sosnoskie and Hanson 2015; Sutton et al. 2006). The adoption of reduced tillage in processing tomatoes favors the spread of field bindweed which can be suppressed by frequent soil disturbance. Even hand-weeding can serve as a selective pressure; Echinochloa crus-galli subsp. Oryzicola, a form of barnyardgrass that mimics cultivated rice both in physical form and phenology, is difficult to visually identify and may escape removal in labor-intensive production systems (McElroy 2014).

Managing Herbicide Resistance When it comes to managing herbicide resistance, the Weed Science Society of America (WSSA) has a list of strategies to employ in order to increase the diversity of tools in a production system. However, these tools have value beyond the prevention and mitigation of resistance; varying the types and timing of disturbances should help to combat difficult to control species that arose in response to the repeated use of a weed control strategy. Some of the best management practices endorsed by the WSSA include:

Continued on Page 14

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Figure 2: Herbicide resistance is an evolutionary process. Herbicides do not actively mutate the target weeds, rather, the repeated use of an active ingredient over space and time eliminates susceptible individuals (plain green patches) from a population leaving only the resistant plants (orange patches with the “R”) to reproduce and set seed. Over time, the resistant trait becomes dominant in the population as susceptible individuals die out without successfully reproducing.

Continued from Page 12 Using multiple herbicide modes of action and applying herbicides at the proper rates and times

Preventing the movement of weeds within and between systems

Adopting mechanical weed control when appropriate

Reducing weed seed production and seed return to the soil seedbank

Rotating crops to diversify the type and timing of weed control and production practices Emphasizing cultural practices that are suppressive to weeds

Bring the heat on hard-to-kill weeds and insects with

SOURCES:

Hanson et al. (2013) Selection pressure, shifting populations, and herbicide resistance and tolerance. ANR Publication 8493. https://anrcatalog.ucanr. edu/pdf/8493.pdf. Last accessed on May 16, 2019. Heap (2019) The International Survey of Herbicide Resistant Weeds. http:// weedscience.org/ Last accessed on May 14, 2019. McElroy (2014) Vavilovian mimicry: Nikolai Vavilov and his little-known impact on weed science. Weed Sci. 62:207-216.

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Petit et al. (2011) Weeds in agricultural landscapes. A review. Agron. Sustain. Develop. 31:309-317.

Shrestha et al. (2007) Sub-surface drip irrigation as a weed management tool for conventional and conservation tillage tomato (Lycopersicum esculentum Mill.) production in semi-arid agroecosystems. J. Sustain. Agric. 31:91–112. Smith et al. (2000) Palmer amaranth (Amaranthus palmeri) impacts on yield, harvesting, and ginning in dryland cotton (Gossypium hirsutum). Weed Technol. 14:122-126.

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Sosnoskie and Hanson. (2015) Field bindweed (Convolvulus arvensis) control in early and late-planted processing tomatoes. Weed Technol. 30:708-716. Sutton et al. (2006) Weed control, yield and quality of processing tomato production under different irrigation, tillage and herbicide systems. Weed Technol. 20:831–838. White et al. (1998) The control of rodent damage in Australian macadamia orchards by manipulation of adjacent non-crop habitats. Crop Protect. 17:353-357.

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Morgan et al. (2001) Competitive impact of Palmer amaranth (Amaranthus palmeri) in cotton (Gossypium hirsutum). Weed Tech 15:408-412.

Pirchio et al. (2018). Autonomous mower vs. rotary mower: effects on turf quality and weed control in tall fescue lawn. Agronomy 8:15.

Comments about this article? We want to hear from you. Feel free to email us at article@jcsmarketinginc.com

Del Pozo-Valdivia (2019) Weeds serving as alternative hosts for diamondback moth. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=29228. Last accessed on May 14, 2019.

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All photos courtesy of Caroline Eberlein.

Do Liquid Digestates, By-Products of Bioenergy Production, have Nematode-Suppressive Potential? BY CAROLINE EBERLEIN | Department of Nematology, UC Riverside, Parlier, California RUIHONG ZHANG | Department of Agricultural and Biological Engineering, UC Davis ABDELHOSSEIN ADELATI | Department of Agricultural and Biological Engineering, UC Davis ANDREAS WESTPHAL | Department of Nematology, UC Riverside, Parlier, California

Experimental tank wagon for band application of liquid digestate in a walnut orchard. The digestate is pumped via a custom nozzle underneath the tree row. Food hygiene guidelines need to be observed.

arge amounts of organic wastes of food or animal origin accrue in cropping systems and in the food industry. Traditionally, many of these byproducts could remain in the agricultural production chain. For example, almond hulls may be used as dairy feed. Others ended up in landfills. With the continually increasing amounts, and for other market changes, alternative uses are urgently needed. When converting these energy-rich materials to biogas, organic matter from food waste or animal manure are processed through anaerobic digestion by microorganisms in specialized biodigesters. The resulting biogas is then used as fuel for electricity and heat generation or put into cars and other vehicles as transportation fuel. The anaerobic digestion process has been favored to reduce the emissions of methane and other gases from organic waste materials during natural decomposition. Although animal manure is probably the most widely used substrate for anaerobic digestion worldwide, food waste is another organic substrate due to its high methane production potential. Besides biogas, a liquid effluent called anaerobic digestate is also produced from digestion processes. The disposal of such residues represents an environmental and economic challenge. A meaningful use of this material would favorably impact environmental

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stewardship by reducing waste disposal issues, and could benefit agriculture by recycling the nutrients in the digestate for plant growth benefits.

Plant-parasitic Nematodes Plant-parasitic nematodes are a constraint in crop production, especially in perennial crops in California. Long cropping cycles, soils that favor high nematode densities, and favorable climate conditions, increase nematode reproduction. In the past, nematodeinfested fields have been effectively treated with soil fumigants before planting or with various post-plant nematicides. The use of fumigants and non-fumigant nematicides is challenged by human and environmental health concerns. For example, regulation limits the use of 1,3-dichloropropene materials under so-called township cap. The quantity that may be used per year is restricted per 36 square miles (=Township). Clearly, more environmentally friendly alternatives to the use of these chemicals are urgently needed.

Environmentally Friendly Alternatives A number of studies have investigated the potential of these digestates as

July /August 2019

bio-fertilizers. Because these wastes originate from plant material they are nutrient rich and their use fits into a cyclic production of returning byproducts to the primary field production. Such cycling has positive environmental effects. In some studies, the potential of these digestate for managing pests and diseases in different crops were explored. In a study in Germany, anaerobically digested maize silage suppressed the sugar beet cyst nematode, a major pest of sugar beet production in Central Europe. Using organic materials as nematode management tool is challenging because such materials can vary greatly in their physico-chemical composition. This composition likely will impact the nematode-suppressive potential of digestates. It probably depends not only on the substrate but also on the conditions during anaerobic digestion. In a project supported by the Department of Pesticide Regulation (DPR), digestates from different sources of different processing conditions and substrate base as well as varying chemical constitution showed differences in nematode suppressive potential. This illustrated the challenge of working with organic materials,

Continued on Page 18

Experiment with pepper in microplots. Microplots are contained areas of two foot diameter and five feet long culvers perpendicularly inserted in the ground, and filled with test soils. Each of these plots allow for precise application amounts of digestates or other treatments.

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Watermelon experiment for testing for efficacy of digestates to suppress nematode population densities. Watermelon seeds are grown in root-knot nematode-infested soil after at-plant application of digestates for one month. Then roots are harvested and examined for nematode-induced galling.

Continued from Page 16 and the need to quickly and easily characterize the nematode suppressive potential of digestate. For this purpose, a robust fast turn-around bioassay was tested in three different incubation environments, two different growing containers, and with two different nematode life stages as inoculum. In this test, a single radish seed is planted into nematode-infested soil in small containers after a small amount of digestate has been added. After four to five days, a staining procedure is used to visualize the nematode that have penetrated the young radish roots. Low

numbers compared to roots that did not receive the digestate suggest some suppression of nematode infection. In this project, results were similar in the different contexts, and the digestate tested was able to suppress nematodes in all contexts. Based on these results, this bioassay may be useful as a quality control tool for measuring nematode suppressivenesss of organic liquids that could possibly be implemented by commercial laboratories.

Temperature

Temperature is one of the most significant parameters influencing anaerobic digestion. Biogas generation through the anaerobic digestion process can take place over a wide range of temperatures, from as low as 50 F (10 °C) to 135 F (55 °C), corresponding to psychrophilic <68 F (< 20°C ), mesophilic 68 to 104 F (20-40°C ), and thermophilic >104 F (>40°C ) conditions. Because of an increased Radish seedling four days after seeding into nematode-infested biogas yield, soil and digestate amendment. This seedling has sufficient roots to in most cases, digesters are allow for examination of nematode infection. operated under 18

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July /August 2019

mesophilic or thermophilic conditions. Temperature does influence the activity and composition of microorganism groups. This influences the methane yield and likely the constitution of the resulting digestate possibly influencing the nematode suppressive potential. Of course the substrate, which can vary between different organic wastes will impact this constitution as well. The substrate and the process may therefore impact what secondary metabolites are produced during digestion, and thus nematode suppressive potential. Therefore, liquid manure and food waste both processed either mesophilically or thermophilically were used in a number of experiments to study the influence of these two factors.

Food Waste Versus Manure In the radish bioassay with the sugar beet cyst nematode, no difference in root penetration was found between the two substrates (food waste vs manure) but a significant difference was found between the two processes. The thermophilic digestates were able to reduce nematode root penetration by more than 50 percent compared to the mesophilic digestates. In greenhouse experiments, the digestates of different substrates and processes were used to treat watermelon in soil infested with Meloidogyne incognita (root-knot nematode, RKN) to test the versatility of nematode suppression. After fiveweeks incubation, plants were harvested and roots evaluated for nematode damage (root galling, and number of

In greenhouse experiments, the digestates of different substrates and processes were used to treat watermelon in soil infested with Meloidogyne incognita (root-knot nematode, RKN) to test the versatility of nematode suppression.

egg masses). Nematode-induced galling was similar or higher in plants from the digestate treatments than for plants from the control. A numerically small but significant reduction in root galling was found in food waste compared to manure. None of the digestates resulted in better plant growth when compared to the control.

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Small Field Experiments Microplot and small field experiments were conducted to implement the findings of controlled conditions into practical field contexts. Application strategies included drench application of the digestates as pre- or post-planting treatments. In a bell pepper microplot trial in RKN-infested soil, five different digestates were applied at planting. Three months later, plants were harvested and roots assessed for nematode suppression. The digestates did not result in improved plant growth compared to the control treatments. Nematode damage in roots was not reduced after treatment with digestates. Although, populations for RKN after harvest, were lower in plots treated with mesophilic manure and similar to the nematicide control. Similar studies were conducted with almond and walnut and ring nematode, root-knot and root lesion nematodes but results were somewhat variable indicating the need for improved application strategies. In summary, some beneficial effects of thermophilic digestates were observed on plant growth and nematode suppression

Continued on Page 20

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Root-knot nematodes are known for their root changing effects. Galls or the name-giving knots are visible on young seedlings, and older plants. Water and nutrient uptake are impeded by such unusual roots.

Continued from Page 19 compared to mesophilic digestates under controlled conditions. In preliminary tests in the greenhouse, nematode suppression was observed but under field conditions with different nematode pests of different crops, inconsistent results were obtained. Further experimentation is needed to elucidate the chemical nature of compounds conferring nematode suppression, and how to make use of this beneficial capacity of the waste product digestate. The environmental and economic benefits of cycling plant nutrients and concomitantly suppressing soil pests make this a valuable endeavor.

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Management Practices to Improve

Soil Function BY SARAH LIGHT | Agronomy Advisor, Sutter, Yuba, and Colusa Counties

oils are essential for life on earth. In addition to the fundamental role of soil in agriculture, soils support building and recreation, filter and store water, recycle nutrients, protect our communities from flooding, sequester carbon, and due to the wide microbial diversity of soils, have even been a source of antibiotic and prescription drug discovery. Soils are alive! In fact, up to one billion bacterial and several yards of fungal hyphae can live in a single gram of soil. These microbes, invisible the naked eye, are at the core of many of our soil building management practices.

is very challenging, if not impossible, to restore. As President Franklin Delano Roosevelt once said, “the nation that destroys its soil, destroys itself.” The United States Department of Agriculture (USDA)/National Resources Conservation Service (NRCS) estimates that the annual cost of soil erosion in the United States alone is $44 billion. While we cannot re-create soil once it is destroyed, we can employ on farm management practices to reduce the risk of soil destruction and to increase soil function.

The main principles of soil health are to maintain soil cover, minimize soil disturbance, keep a living root in the Despite being one of our most soil, and incorporate plant diversity. important natural resources, we These principles are intended to keep may not often think about soil as soils alive by encouraging flourishing something that needs to be built or soil microbial communities and protected. Unfortunately, soils globally physically protecting soils from either and in the United States are being loss or structural damage. Soil microbes destroyed at a rapid rate. Soil is a nonare a critical part of soil health because renewable resource and once a soil of the role they play in nutrient cycling has been degraded to the point where and building soil aggregates. Soil it cannot be used to produce crops, it aggregates are clumps of soil particles that are bound together, leaving more available space for air and water. Aggregates are held together by organic matter (like roots), organic compounds (produced by soil microbes), and fungal hyphae. Microbes get nutrients and energy from the carbon found Photo courtesy of Jeff Mitchell. in soil organic matter. Figure 1: Farmers and consultants examining crop This is the reason that many soil health residue and root growth and development in strip till practices involve corn in Chowchilla, California. increasing soil organic matter—it provides 22 Progressive Crop Consultant

July /August 2019

food for soil microbes which increases their activity and population. Consider this: soil microbes are necessary for the conversion of nitrogen from one form to another (like ammonium to nitrate) and they need carbon to thrive.

Maintaining Soil Coverage Bare soil is more susceptible to wind and water erosion, as well as to surface compaction. Our topsoil is the most nutrient-rich part of the profile so when we lose soil to erosion we are losing our most valuable soil to the environment. Although loss of soil to erosion may seem minor from year to year, when we consider that it takes 500 years to form an inch of topsoil, if we are losing just 1/100 of an inch of topsoil to erosion a year, we are still losing soil five times faster than it is being formed. Surface compaction develops when rain and irrigation water hits tilled soil, which forms a soil crust. Maintaining soil coverage throughout the year physically protects soil and provides a range of other benefits like reducing soil evaporation rates, moderating soil temperature, and suppressing weed growth. In annual systems we can keep our soil covered by planting a cover crop during our fallow season. Keeping crop residue on the field is also effective (Figure 1).

Minimize Soil Disturbance As described above, soil microbial activity is critical for soil aggregate formation and stability. Tillage practices disrupt this activity and break the fungal hyphae and roots that are holding aggregates together. Although it may seem that tillage increases soil pore

Continued on Page 24

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to remember the rules of soil fertility tool for maintaining including the 4Rs and the Law of the consistent soil carbon Minimum. As a reminder, the 4Rs refer levels. In general, to the Right Rate, the Right Source, the keeping our soils alive Right Timing, and the Right Mode of throughout the year will Application. These principles allow us increase soil function. to optimize our fertilizer application Cover crops that are inserted into rotations as by ensuring the greatest nutrient use efficiency. This reduces the risk of loss possible are a means for achieving this soil health to the environment and can increase the bottom line. Liebig’s Law of the principle. As part of a Minimum refers to the idea that the California Department limiting factor has to be addressed of Food and Agriculture Photo courtesy of Jeff Mitchell. first. In other words, the soil issue (pH, Healthy Soils Program Figure 2: Direct seeding corn into wheat stubble in nutrient status) that is most restricting grant, my colleagues yield is the one that has the greatest and I are experimenting Five Points, California. potential to improve yield. If the pH is with planting cover yield limiting, no amount of fertilizer crops during the fallow Continued from Page 22 application will fix this problem. season. In San Joaquin County, UC Cooperative Extension farm advisors space, this benefit is short lived. This is Michelle Leinfelder-Miles because individual particles break off and Brenna Aegerter, are aggregates in recently tilled soils and Photo courtesy of Sarah Light researching the effects of can fill in pore spaces. A healthy soil a warm-season legume has about 50 percent open pore space cover crop between winter (half filled with air and half filled with small grains rotations. water). Soil pores are where roots grow In Sutter County, Amber and microbes thrive. There are other Vinchesi-Vahl and I are management practices to minimize researching the effects soil disturbance. These include not of a winter cover crop, at working or driving over soil when it is different seeding rates, wet, distributing tractor weight over a between summer cash larger surface area to reduce pressure crops (Figure 3). Our on specific points in the field, and projects are entering the reducing the number of trips over a Photo courtesy of Sarah Light. second of a third-year field when possible. Even if converting Figure 3: Winter vetch cover crop (with volunteer project, and we look to no-till isn’t realistic for your farm, forward to reporting the wheat) in Meridian, California. reducing the number of passes with results on soil health and the disc over a field and using vertical crop yields in the future. instead of horizontal tillage are ways to Maintaining soil health is the long game minimize soil disturbance. California and changes may not be apparent for Incorporate Plant Diversity farmers in a number of regions are several years. However, the more the now experimenting and sharing their management practices outlined above In annual systems this is called crop experiences with reduced disturbance are incorporated into our farming rotation. Crop rotation is beneficial production systems like direct seeding systems, the greater the likelihood of for many reasons. It breaks disease into crop residue from the previous long-term viability and protection of cycles by starving out pathogens that crop with little soil disturbance (Figure arable land. In addition to the benefits can only thrive on specific plants 2). Ongoing summaries of this work already discussed, soil water dynamics (or plants in a specific family). In may be found at http://casi.ucanr.edu/ can be improved by increased water addition, crops with different rooting infiltration and water storage. Every depths will mine nutrients, release Keep a Living Root in the Soil farming system is unique and some of carbon compounds, and improve soil the practices may be cost-prohibitive structure at different depths of the soil Plant roots release small carbon-based or not viable for some other reason. profile. Finally, plants form symbiotic compounds called root exudates, The goal should be to incorporate as relationships with various microbes, which are a mix of sugars, amino acids, many of the practices that will work in but these relationships are often species enzymes, organic acids and other our farm systems as often as we can. specific. When we incorporate plant compounds. These exudates can help Every opportunity to build and protect diversity into our systems we also build breakdown mineral nutrients, leading our soil will ensure the long-term to increased soil fertility. They also serve up the diversity in our soil microbial economic viability of our farms, as well populations. In perennial systems, plant as a source of food for soil microbes. as food security for our growing global diversity can be achieved by planting a Maintaining a living root in the soil population. helps keep our soil alive throughout the cover crop in between crop rows. year. Many beneficial microbes cannot Although soil biology is an important Comments about this article? We want survive in a low-carbon environment component of soil health, it is not the to hear from you. Feel free to email us at and keeping a living root is yet another article@jcsmarketinginc.com only consideration. It’s also important 24 Progressive Crop Consultant

July /August 2019

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Iron Deficiency

in Fruit and Nut Crops in California BY MOHAMMAD YAGHMOUR, | Area Orchard Systems Advisor, Kern County PHOEBE GORDON, | Area Orchard Systems Advisor, Merced County

icronutrients play a very important role in fruit and nut tree growth and development. Iron (Fe), which is an immobile micronutrient in the plant, is associated with chloroplasts and plays a role in chlorophyll synthesis. While Fe is considered the fourth most abundant element in the Earth’s crust, approximately five percent by weight, iron deficiency is a worldwide problem, and a common micronutrient deficiency in fruit and nut crops (Figure. 1) though it is uncommon in California.

description of pH. It indicates the concentration of H+ ions (protons) in a solution. Soils with low pH have more H+ ions than soils with a high pH. Because the equation is actually a logarithm (Equation 1), the amount of H+ ions does not increase linearly as pH decreases, it increases by a factor of 10. Thus, water with a pH of 5 has 10 times the amount of H+ protons than water with a pH of 6. Therefore, it is progressively harder to correct soil pH the farther it is from 7.

Many orchards in the Central Valley are on semi-arid soils in areas where the evapotranspiration exceeds precipitation. Arid and semi-arid soils can also be found in the southwestern USA and the Mediterranean areas. In this article we will be focusing more on calcareous soils with free calcium carbonate (CaCO3) and soil solution pH in the alkaline range (i.e. above 7.5).

Equation 1: equation for conversion of the concentration of H+ ions in solution to pH. Since the equation is logarithmic, there is a 10x difference between consecutive values.

pH = -log[H+]

Soil pH is important as the different soil minerals that contain and release iron (Fe) into the soil-water solution decrease in solubility as pH increases, which results in only a tiny fraction Before we get into the specifics of iron of the total Fe that is in the soil to in the soil solution, we’ll give a brief be available. In general, iron is more soluble and more available as pH decreases (acidic soils). Plants absorb some iron by diffusion at the root tips from the soil solution, and iron deficiency in California is mainly due to plants’ inability to take up iron due to soil factors such as poor soil aeriation and/or high concentration of HCO3- in the soil. Photo courtsey of Mohammad Yaghmour.

Figure 1. Advanced iron deficiency on almond tree in Kern County. Interveinal chlorosis are a typical symptoms of iron deficiency.

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Under low iron availability in the soil, the ability of trees and plants to mobilize iron immediately around the root is due to differences in genes between species. Scientists have categorized plants either as “Strategy I’ or ‘Strategy II’ based on their ability to mobilize Fe in the soil and make it available for uptake. Strategy I plants include all plants except grasses and include fruit and nut trees, while Strategy II plants comprise grasses such as wheat and corn. Under Fe deficient soil conditions, Strategy I plants excrete H+ into the soil, which acidifies it and makes iron more available for uptake. In poorly aerated calcareous or saturated soils, carbon dioxide will become trapped in the soil due to poor gas exchange with the atmosphere. This will cause the production and accumulation of bicarbonates as a result of the interaction between CO2 and calcium carbonates in the soil. Bicarbonates react with the H+ released by roots and interfere with their ability to increase iron availability.

Symptoms of Iron Deficiency The development of Fe deficiency symptoms is most prominent on young, newly developing leaves (Figure 2, see page 28) because this element is immobile in the plant. The symptoms are characterized by interveinal chlorosis, (Figure 3, see page 28). Under severe conditions, leaves have a white coloration due to the disappearance of chlorophyll, and leaves can turn necrotic and abscise. Leaf chlorosis due to iron deficiency reduces photosynthesis and will result in reduced fruit yields and fruit quality. These attributes are only for iron deficient plants; overfertilizing with iron will not increase these functions in the

Continued on Page 28

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Continued from Page 26 plant.

Pre-Plant Management of Iron Deficiency The first step in assessing an orchard is site selection, followed by collection of representative soil samples for analysis based on the United States Department of Agriculture (USDA)/ National Resources Conservation Service (NRCS) soil survey map. Send these soil samples to a commercial laboratory you trust to look at soil pH and the presence of free lime. It’s also helpful to get a water analysis to look for water pH and bicarbonates. When choosing a site, try to plant in a welldrained soil. Adequate root aeration will reduce the likelihood of iron chlorosis occurring. If the irrigation water contains more than 2 meq/L Photo courtsey of Mohammad Yaghmour. of bicarbonates, you may consider acidifying the water to a pH of 6.5 Figure 2. Iron deficiency on newly growing leaves on an almond tree in Kern County with leaves showing to reduce bicarbonate levels by 50 interveinal chlorosis. percent and prevent lime buildup in the soil and in your irrigation system. An agricultural laboratory can do a capacity potentially making the capital use, as substituting one acid for another titration curve, which will tell you how investment too expensive for smaller can result in incomplete or overmuch acid to add to decrease the water farms to consider. acidification. Urea sulfuric acids, such pH. We do not recommend decreasing as N-PHuric 10/55 and US-10, will also Acidification can be expensive and irrigation water pH below 5.0. acidify the soil and are safer to handle, in extreme cases may not be viable to Alternatively, 133 pounds of 100 percent however, application rates should not reduce pH in soils with a lot of free sulfuric acid will neutralize 1 meq/l per exceed nitrogen (N) crop requirements, lime, as it will require large quantities of acre-foot of bicarbonate in irrigation which limits its use for acidification. acid forming amendments to react with water. Water acidification can be Some growers use a “sulfur burner”, soil lime before the bulk soil pH begins achieved by using acids such as sulfuric which will convert elemental sulfur to decrease. It takes approximately or phosphoric acid. Make sure you tell into sulfurous acid (H2SO3) by burning half a ton of soil sulfur to break down your laboratory what acid you intend to elemental one percent calcium carbonate in one sulfur in a acre-inch of soil. To manage these costs, small furnace soil amendments such as elemental producing sulfur or sulfuric acid can be banded or sulfur dioxide shanked in the tree row before planting. (SO2). Combination of However, warm soil temperatures and soil bacteria are needed to convert the SO2 and water elemental sulfur to sulfuric acid and in the machine depending on the source of sulfur and will form its influence on particle size, structure, sulfurous acid and solubility of the sulfur this may take that is injected in the irrigation several weeks to years to break down. Acids work much faster but are more system. expensive. It is important to remember Sulfurous that any acidification will break down acid is safer free lime in the soil before the bulk soil than sulfuric pH is changed. acid injection. Sulfur Rootstock choice is one of the most burners have important choices you or your client a minimum will make before planting an orchard. design and This choice should be based on the Photo courtsey of Elizabeth Fichtner. production site challenges such as pH, salinity, Figure 3. Iron deficiency on newly growing prune leaves.

28 Progressive Crop Consultant

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Continued on Page 30

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Change in pH for a Loam Soil

Pounds of Soil Sulfur to Modify a 6-inch Slice

8.5 to 6.5

2000

8.0 to 6.5

1200

7.5 to 6.5

500

7.0 to 6.5

100

Table 1. Amount of soil sulfur needed to modify a loam soil. Adapted from the Western Fertilizer Handbook, 9th Edition.

Continued from Page 28 nematodes, and risk of bacterial canker, for example. If high soil pH and concern about iron deficiency is the most important factor to resolve, then use of Fe deficiency tolerant rootstocks is a good solution. Some of the rootstocks that are considered tolerant include some of the (peach X almond) hybrids such as Hansen 536, Bright’s, Titan, and Paramount (GF 677). However, these rootstocks are very susceptible to other soil issues such as poor drainage and root diseases, so pick your rootstock carefully. Other rootstocks tolerant to Fe deficiency are Krymsk86 which is a peach/plum hybrid used for almonds and Gisela 5 used for cherry trees.

Post-Planting Management of Iron Deficiency After planting the trees, if your soils do not have a large amount of free lime, the best management practice is acidifying the soil around the root zone. This can be done using elemental sulfur or the injection of acids as described before, however you can easily damage your trees through acid injection so follow directions carefully. Do not apply sulfuric acid in established orchards at more than 1500 lbs per treated acre to prevent tree damage. 30 Progressive Crop Consultant

Elemental sulfur takes longer but is safer for the trees. It is often more economical to acidify a band of soil rather than attempting to acidify the entire root zone. Another way to correct iron deficiency after planting is to apply foliar and soil chelated Fe which will result in a faster response. However, it is short-lived, expensive, and can be leached below the root zone under heavy irrigation. Chelated Fe most likely will need to be applied multiple times in the orchard’s lifetime. Applications of ferrous sulfate to the soil or the tree is a cheaper option compared to chelated Fe. However, in calcareous soils it will very quickly become unavailable for uptake and is not an appropriate option in these soils.

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July /August 2019

Sources: Elkins, R., and Fichtner, E. (2012). Causes and control of lime-induced Fe deficiency in California fruit and nut crops. CAPCA (California Association of Pest Control Advisers) Advisor. August 2012. Lauchli, A., and Grattan, S., R. (2012). Soil pH Extremes in: Plant Stress Physiology. CAB International, Editors: S Shabala, pp.194-209. Sanden, B., L., Prichard, T., L., and Fulton, A., E. 2016. Assessing and Improving Water Penetration in: Pistachio Production Manual. UC ANR publication 3545, Editors Louise Ferguson and David Haviland, pp. 141-152. Tagliavini, M., and Rombola, A., D. 2001. Iron deficiency and chlorosis in orchard and vineyard ecosystems. European Journal of Agronomy 15: 71-92.

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How to Optimize IPM and Nutrient Management using Aerial Drone Technology Mark Dufau, Director of Business Development for AeroVironment

CE Credits: 30 Minutes; L & R

5:00PM Mixer/Trade Show

CE Credits: 30 Minutes; Other

3:00PM

7:00PM Jason Bird

Magician and Illusionist

Managing Botrytis in a Challenging Year

Jason Bird creates experiences that inspire people. He reawakens their sense of wonder and reminds them of how cool it is to be alive. In addition to the millions who have seen him on television, Jason Bird has cast his spell for audiences around the world in large theatrical venues as well as intimate settings.

Gabriel Torres, UCCE Farm Advisor, Tulare County

CE Credits: 30 Minutes; Other

3:30PM

The Latest in HLB and Asian Citrus Psyllid Management Greg Douhan, UCCE Area Citrus Advisor for Tulare, Fresno, and Madera Counties

CE Credits: 30 Minutes; Other

6:00PM Dinner

32 Progressive Crop Consultant

Future of Agriculture Chemicals in California

July /August 2019

Jason Bird will perform small group illusions during the trade show / mixer from 5-6PM

*PRE-REGISTER TO BE ENTERED TO WIN A TRAEGER PRO SERIES GRILL

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VISALIA CONVENTION CENTER Bringing 303 E Acequia Ave,Crop Visalia, CA 93291

Consultants

Attendee Registration

Together Workshops and Seminars Mixer & Networking Meals Included

PUBLICATION

7.5 Hours of PCA

(Breakfast, Lunch and Snacks)

Full Gala Dinner Live Entertainment

Other: 5.75 Laws and Regulations: 1.7526th-27th September

Visaliaof Convention 9.0 Hours CCA Center

(Jason Bird, Magician and Illusionist)

Over 50 Exhibits

DoAgenda/Pending you wish to receive/continue receiving our free monthly Publicatons? (Tentative CE Approval) West Coast Nut

Progressive Crop Consultant

Yes No

Organic Farmer

Prizes

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Full Name: Friday

September 27

PCA Hours:

8:00AM

Company:

Label Update

Email:

CE Credits: 50 Minutes; L & R

CCA Hours:

Cell:

Phone:

9.0

$100

8:50AM County:

Address:

7.5

per attendee Evaluation of Mating Zipcode: State: Disruption as Part of an IPM September 26th-27th 10:30AM Visalia Convention Center (Check only one) Program Secondary Business/Occupation (Check all that apply) Trade Show

City:

Primary Business/Occupation 303 E. Acequia Ave. Chuck PCA PCABurks USDA Independent PCA Independent PCA Visalia, CA 93291 CE Credits: 30 Minutes; Other Dani Casado, Ph.D. in Applied Chemical Ecology, Sutterra CCA CCA Independent CCA Independent CCA Jeannine Lowrimore, Pacific Bio Control Workshops Grower Grower Ag Retailer Ag Retailer CE Credits: 40 Minutes; Other Applicator Applicator Other Other Seminars

11:00AM

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commodity per line) Commodities Breakfast / Going(One Above and Beyond for Your Grower – Keeping them Compliant

Acres

Commodities

Panel—Top Insects Drink Plaguing Ticket on Us Acres Mixer California Specialty Crops— Networking BMSB, Mealy Bugs/NOW Meals Included Spotted Wing Drosophila

(One commodity per line)

Patty Cardoso, Director of Grower Compliance for Gar Tootelian, Inc.

Attendee Tickets cost $100 per person. Please list the full name of each attendee as appear on your name badge. Attendee Name:

(Gala Dinner, David Haviland (Mealy Bugs/NOW) UC Lunch, Breakfast, and snacks) Cooperative Extension, Kern County, KentitDaane you want to (SWD) Cooperative Prizes Extension Specialist, UC Berkeley, Jhalendra Rijal (BMSB) UCCE IPM Advisor for northern San Joaquin Valley

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PRE-REGISTER TO BE ENTERED TO WIN A TRAEGER PRO SERIES 780 PELLET GRILL

# Of Attendees:

12:00PM Lunch

x $100

Regulatory Impacts on California Crop ProtectionTotal: $ 12:15PM Industry A New Approach to IPM Signature Matthew Allen, Director, California Government Affairs,

PUBLICATION

Western Growers

7:30AM

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FOR MORE DETAILS OR TO REGISTER ONLINE VISIT Break

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Please Mail Applications to 1:00PM Progressive Crop Consultant P.O. Box 27772Adjourn Fresno, CA 93729 July /August 2019

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For Sponsorship Opportunities call (559) 352-4456 TODAY! September 26-27, 2019

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Company Name: ____________________________________________________________________ Company Address: ___________________________________________________________________

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Signature: _________________________________________________Date: ____________________ Future of Agriculture STANDARD BOOTH OPTIONS: Check One Booth Attendants: Chemicals in California 4:00PMEnter all of the information below as you wouldSpeaker like it to appear on name badges. TBD Indoor Booths Navigating Fungal Diseases CE Credits: 30 Minutes; Other

Company Name: Themis Michallides, Professor and Plant Pathologist UC Davis

1:00PM

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4:30PM 2)

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Paraquat Closed Transfer Additional Attendees: $100 per additional attendee System (New EPA Richard Kreps, CCA are included with eachGuidelines for 2020) 1) 3) Two conference registrations Getting the Most out of Your Soil

booth purchase. registration fee for each additional attendee.

2:30PM

Charlene Bedal, West Coast Regional Manager, HELM AGRO2)US

CE Credits: 30 Minutes; L & R

How to Optimize IPM(ifand Optional Extras: Check applicable) Nutrient Management using Advertiser - Special Pricing Aerial Drone Technology

TOTAL: 5:00PMPlease enter the total amounts for all of the options you selected below. Mixer/Trade Show Standard Booth: $

Mark Dufau, Director of Business Development for Do youAeroVironment currently advertise in our publications? CE Credits:

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West Coast Nut, Progressive Crop Consultant, and Organic Farmer (Total Package Savings of $150)

Additional Attendees: $

Full Page Ad in the NEW Digital Guide 3:00PM

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Bag Insert ManagingTote Botrytis in a Challenging Year Non-Advertiser Gabriel Torres, UCCE FarmPricing Advisor, Tulare County

Digital GuideOther & Tote Bag Insert Combo CE Credits: 30 Minutes;

With this option you save $50, receive a tote bag insert and a full page ad in our NEW Digital Guide!

3:30PM Digital Guide Full Page Ad

Your in ad will appear in our NEW Digital Guide Latest HLB and Asian

The Citrus Psyllid ToteManagement Bag Insert

Greg Douhan,Put UCCE Citrus for Tulare, anArea insert intoAdvisor our tote bag to go to every attendee. Fresno, and Madera Counties

Magician and Illusionist

Total Amount Due: $Jason Bird creates experiences that inspire people. He reawakens their sense of wonPayment and completed formder are and required to secure your of booth. reminds them howPlease coolmail it is to payment with this completed form to JCS Marketing PO Box 27772, Fresno, CA In addition to the millions who 93729. Make checks payable tobe JCSalive. Marketing. **All credit card payments are have subjectseen to a 3% processing fee. him on television, Jason Bird has cast his spell for audiences around the Interested in a FREE booth? world in largeopportunities theatrical venues as well as Check out our sponsporship at wcngg.com or call today for special custom pricing onsettings. advertising packages. intimate 559-352-4456

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show / mixer from 5-6PM $1,000,000 for each occurrence. Mail to JCS Marketing PO Box 27772,during Fresno,the CAtrade 93729.

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34 Progressive Crop Consultant

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2-Day Agenda

VISALIA CONVENTION CENTER 303 E Acequia Ave, Visalia, CA 93291

Workshops and Seminars Mixer & Networking Meals Included

7.5 Hours of PCA

(Breakfast, Lunch and Snacks)

Full Gala Dinner Live Entertainment

Other: 5.75 Laws and Regulations: 1.75

9.0 Hours of CCA

(Jason Bird, Magician and Illusionist)

Over 50 Exhibits

(Tentative Agenda/Pending CE Approval)

Friday September 27

Prizes

8:00AM

Label Update

CE Credits: 50 Minutes; L & R

8:50AM

Evaluation of Mating Disruption as Part of an IPM Program

7:00AM

10:30AM

Trade Show

Chuck Burks USDA Dani Casado, Ph.D. in Applied Chemical Ecology, Sutterra Jeannine Lowrimore, Pacific Bio Control

CE Credits: 30 Minutes; Other

CE Credits: 40 Minutes; Other

11:00AM

Panel—Top Insects Plaguing California Specialty Crops— BMSB, Mealy Bugs/NOW Spotted Wing Drosophila

Breakfast / Going Above and Beyond for Your Grower – Keeping them Compliant Patty Cardoso, Director of Grower Compliance for Gar Tootelian, Inc.

David Haviland (Mealy Bugs/NOW) UC Cooperative Extension, Kern County, Kent Daane (SWD) Cooperative Extension Specialist, UC Berkeley, Jhalendra Rijal (BMSB) UCCE IPM Advisor for northern San Joaquin Valley

CE Credits: 60 Minutes; Other

12:00PM

9:30AM

Regulatory Impacts on California Crop Protection Industry

7:30AM

Trade Show

CE Credits: 30 Minutes; Other

Matthew Allen, Director, California Government Affairs, Western Growers

CE Credits: 30 Minutes; L & R

Lunch

12:15PM

A New Approach to IPM Surendra Dara, Entomology and Biologicals Advisor, University of California Cooperative Extension

CE Credits: 30 Minutes; Other

10:00AM

1:00PM

Break

Adjourn

July /August 2019

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Magnesium Deficiency in Grapes

Figure 1. Magnesium deficiency in Scarlet Royal table grapes. Photo courtsey of Matthew Fidelibus.

BY MATTHEW FIDELIBUS | Extension Specialist, Department of Viticulture and Enology, UC Davis

hen most California grape growers think of macronutrients, nitrogen (N) and potassium (K) are rightfully at the top of list, as these two mineral nutrients are needed in relatively high amounts and are commonly supplemented with fertilizer applications. However, magnesium (Mg) is also considered a macronutrient, though it is needed in much lower amounts than N or K. Even so, it is not uncommon to observe Mg deficiency symptoms, especially in certain grape varieties which appear to be particularly prone to Mg deficiency, including Barbera, Grenache, Redglobe, Thompson Seedless, and Zinfandel. Recently, I have heard from several growers that some of the newer table and raisin grape varieties also appear to be prone to Mg deficiency. Rootstocks also differ in their ability to take up Mg. For example, 1103P is considered to be good at amassing Mg, whereas Riparia Gloire (Vitis riparia), and some V. riparia hybrid stocks are less effective at amassing Mg.

Magnesium Magnesium is a central component of chlorophyll, and by mid to late summer, the leaves of Mg-deficient vines typically develop a distinctive creamy-white chlorosis along the margin of basal leaves. The primary and secondary veins of the leaves retain a dark green color, resulting in a Christmas-tree pattern on the leaf (Figure 1). In red varieties, the leaf margins may develop red color (Figure 1), and in severe deficiencies, the margin may become necrotic, brown colored, and dry. Analysis of petiole samples can be useful in verifying Mg deficiency. Petioles collected at bloom should contain >0.3 percent Mg. Magnesium plays a critical role in enzymatic reactions, including the activation of adenosine triphosphate (ATP). Magnesium deficiency impairs the loading of sucrose into phloem in leaves, thereby causing carbohydrates 36 Progressive Crop Consultant

July /August 2019

to accumulate in leaves, while reducing the supply of carbohydrates to other organs that need them. Thus, Mg deficiency could theoretically limit the vine’s ability to produce and distribute carbohydrates. Australian research has linked low Mg levels in rachises with bunch stem necrosis (BSN), and in such cases, application of Mg reduced BSN. Vines with Mg-associated BSN sometimes, but not always, had leaves with Mg deficiency symptoms. However, studies in California have not verified a link to Mg and BSN.

Magnesium is Moderately Leachable in Soil Magnesium is moderately leachable in soil and tends to be most abundant in subsoil and least abundant in the surface layers, especially on weathered soils. Young vines are more susceptible to Mg deficiency than older vines, probably because the roots of young vines have likely not explored as much of the subsoil as the roots of older vines. Thus, vine age, particularly the age of the root system (if on topworked vines), should be considered when assessing the relatively susceptibility of new varieties to Mg deficiency. Removal with the harvested crop can further reduce Mg in a vineyard, though previous studies suggest that grape berries only amass about 0.2 lbs Mg/ton of fruit. The Mg concentration in soils can be easily measured, but critical soil values have not been established, and it would be very difficult to account for the possible supply of Mg in the subsoil that may be available to the vine. As noted above, Mg deficiency can occur due to insufficient Mg in the root zone, a limited root system, or both. However, Mg deficiency can also be induced by soil acidification (pH < 5.5), which can occur after years of irrigation and fertilization. High levels of other cations, especially K and calcium (Ca) compete with Mg for uptake by roots. Thus, an imbalance in K or Ca

Continued on Page 38

Do you know if your foliar nutrients are getting in?

the form of foliar nutrients do matter! The 5 R’s of foliar nutrition are - apply the Right nutrients, in Right form, at the Right time, in the Right mix and in the Right place. Applying effective nutrients based on a “Science Driven™” approach that DO penetrate leaf tissue ensures your crop is getting the nutrients it needs at the right time. The form of foliar nutrients DO matter. Many foliar nutrient formulations are built on large chain molecules or unreacted oxides or carbonates that are not in-solution. These types of foliar nutrients and others have limited uptake on most leaf surfaces. Agro-K has three main foliar lines – one based on phosphite (Sysstem®) another based on dextrose/lactose (Dextro-Lac®) and a third for organic growers (CLEAN™). They are true 100% nutrient solutions based on low pH small molecular formulations that penetrate leaf tissue rapidly and completely. Rapid and complete uptake of foliar applied nutrients gives growers the ability to effectively meet “peak nutrient demand” timing. Whether you’re applying zinc for rapid leafout to maximize leaf size, or magnesium and iron to ensure maximum chlorophyll development or potassium for fruit bulking, if nutrients do not go in quickly and fully then your foliar dollars are less effective and yield and quality suffers. Make sure you know how well your foliar nutrients penetrate. Ask for SAP analysis comparisons. The chart shows three Agro-K zinc formulations, Sysstem-ZN, Zinc Dextro-Lac and CLEAN Zinc were applied to Viognier grapes on August 8th, along with a commonly available competing zinc amino acid product. Leaves were pulled prior to application and eight days after treatment. SAP analysis, which measures only the free-nutrients available within the leave sap,

Science-Driven Nutrition SM

Viognier Wine Grapes

Zinc levels (ppm) via SAP Analysis 100 96 83

25 4

8 Days After Treatment Pre-treatment n UTC n Sysstem ZN n Zinc DL n Clean Zinc n Competing Zinc Amino Acid

showed that zinc levels prior to zinc applications were the same for all treatments in this fully replicated trial. SAP analysis eight days later shows all three Agro-K foliar products were far more effective than the competing amino acid product in delivering zinc into the leaf tissue where it matters. This year make sure you know the efficacy of your foliar fertilizers before you spray! Talk to an Agro-K representative or your authorized Agro-K distributor and/or PCA for more information on foliar nutrients that truly WORK!. Call 800-3282418, visit www.agro-k.com, or email info@agro-k.com.

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July /August 2019

Continued from Page 36 may induce Mg deficiency. Peacock and Christensen (1996) suggests Mg deficiency is most likely when the Mg saturation of cation exchange capacity of the soil is <5 percent, or when total exchangeable Mg concentration drops below 25 mg/kg. In addition, Peacock and Christensen (1996) notes that exchangeable Mg should be two to three times as high as exchangeable K.

Mild Mg Deficiencies

Mg12

Mild Mg deficiencies, defined as the appearance of symptoms on a few basal leaves in localized vineyard areas, do not contribute to economic loss, and do not require correction. More serious deficiencies should be corrected. To correct Mg deficiencies, growers should consider the various factors, outlined above, which can contribute to Mg deficiency. For example, if soil acidification is found to be a contributing factor, then incorporating lime into the soil can help address Mg deficiency. Dolomitic limestone can increase pH and add Mg. Fertigation and foliar application of Mg fertilizers are effective and may be needed in cases where the deficiency is due to insufficient Mg in soil. Magnesium sulfate may be used for either fertilization method, though other Mg fertilizers are also available. Christensen and Peacock recommended ½ to 2 lbs of MgSO4/vine for fertigation, and 4 lbs MGSO4/100 gallons for foliar application.

Further Reading: Christensen, L.P. and W.L. Peacock. 2000. Mineral nutrition and fertilization. In Raisin Production Manual. L.P. Christensen (Ed.), pp. 102-114. University of California Agriculture and Natural Resources, Oakland. Peacock, B. and P. Christensen. 1996. Magnesium deficiency becoming more common. UCCE Pub. NG5-96

Comments about this article? We want to hear from you. Feel free to email us at article@jcsmarketinginc.com 38 Progressive Crop Consultant

July /August 2019

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All photos courtsey of Florent Trouillas.

Neofabraea Leaf and Twig Lesions

A New Disease of Super-High-Density Olive trees BY FLORENT TROUILLAS | Cooperative Extension Assistant Specialist in Plant Pathology University of California, Davis

Figure 1: Neofabraea leaf lesions on Arbosana olive. 40 Progressive Crop Consultant

July /August 2019

eofabraea leaf and twig lesions were first detected in California super-high-density oil olive orchards in 2016. Since then the disease was found in Glenn, San Joaquin, and Stanislaus Counties. Causal agents of this new disease of olive were identified as Neofabraea kienholzii and Phlyctema vagabunda (syn: Neofabraea vagabunda). Phlyctema vagabunda is known in Spain as the causal agent responsible for the olive leprosy or lepra fruit rot, causing fruit malformation as well as leaf lesion and twig canker. This disease is of increasing concern in Spain, Portugal and Italy. Dr. Trouillas at UC Davis has outlined the disease epidemiology, disease cycle, and determined best spray timings and materials that will help to control this disease.

Disease Symptoms Neofabraea leaf and twig lesions are primarily associated with wounds, such as those sustained during mechanical harvest. Leaf lesions are circular to elongate, necrotic, approximately 0.5 to 1cm in diameter and normally do not number more than one lesion per leaf (Figure 1, see page 40). Twig lesions are reddish-brown in color mainly affecting the bark tissues (Figure 2, see page 42). The disease may occasionally cause fruit rot near the time of harvest. In severely infected orchards, defoliation and fruit loss may occur.

reports of the disease in California olive have included fruit spots in ‘Cortina’, ‘Picholine’ and ‘Frantoio’ varieties in Sonoma county. To date, table olive varieties (Manzanillo and Sevillano) in the Central Valley have not tested positive for Neofabraea leaf and twig lesions.

mechanical harvest, rain events allow for fungal inoculum to be released in the air, leading to infection of the fresh wound sites. Leaf spot symptoms are most visible in March, with defoliation occurring in April and May. Infected leaves and fruits act as inoculum sources for infection the following year.

Infection occurs at the site of plant injuries. In super-high-density oil olives, these wounds are typically associated with damage caused by mechanical harvesters but may also include abrasion sites where leaves or twigs rub against each other. Following

Disease Management Field trials have been conducted for three consecutive years in the highly

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Two fungal pathogens have been identified using morphological and molecular techniques: Neofabraea kienholzii and Phlyctema vagabunda (syn: Neofabraea vagabunda). These pathogens have been associated with bull’s eye rot and canker of apples and pears in the Pacific Northwest. In olive, the disease has been detected primarily from superhigh-density oil olive orchards in Glenn, San Joaquin and Stanislaus counties. The cultivar ‘Arbosana’ is the most susceptible but the disease has also been isolated on occasion from ‘Arbequina’ olives in the Central Valley. It was not found in the Koroneiki cultivar. Previous

Continued on Page 42

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leaf “Neofabraea and twig lesions are

primarily associated with wounds, such as those sustained during mechanical harvest.

“

Figure 2: Neofabraea twig lesions on Arbosana olive.

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July /August 2019

Continued from Page 41 susceptible Arbosana cultivar to determine fungicide efficacy. Results showed that several products were effective in reducing infection by the pathogens and limiting disease incidence. Overall, best disease control was achieved by Topsin M, Vanguard, Inspire Super, Bravo and Ziram fungicides, which provided up to 75 percent reduction in disease incidence. Copper fungicides did not control the disease. Comparison of different fungicide application regimes showed that one to two applications after harvest significantly reduce disease incidence. Two independent wound susceptibility trials were conducted also to determine the duration (0, 1, 2, 3, 4 or 5 weeks) when wounds on leaves remain susceptible to infection, and thus determine the number and timing of fungicide applications required to control Neofabraea and Phlyctema diseases. Results showed that leaves inoculated immediately after wounding (harvest) and those inoculated one week after wounding were the most susceptible to infection. Overall, leaf wound susceptibility to infection declined substantially after four weeks following wounding. This suggests that wounds had healed after four weeks following a wounding event at harvest and that one fungicide application after harvest followed by a second application two to three weeks later should suffice to protect olive trees from infection.

Next Steps Two fungicides were nominated to the IR-4 program in 2018: Ziram (Ziram 76WDG) and difenoconazole/ cyprodinil (Inspire Super). These fungicides were approved

of different “ Comparison fungicide application

regimes showed that one to two applications after harvest significantly reduce disease incidence.

“

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Acknowledgements We are thankful to the Olive Oil Commission of California for funding this research. Comments about this article? We want to hear from you. Feel free to email us at article@jcsmarketinginc.com

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CIDETRAK DA MEC will provide a higher level of insecticide efficacy in killing hatched larval worms and protecting the walnut set that the grower currently sees and counts on by targeting the Codling Moth 1B, 2nd and 3rd flights, with the added benefit of decreasing damaged-nut sites for NOW to later infest. ~ Dr. Douglas Light, USDA-ARS, Emeritus

“

for residue trials at the National Food Use Workshop in September for registration on olives. Strong support was provided based on the afterharvest and winter season usage with expected zero to limit-of-detection residues on the crop in the following harvest season. Ziram is a FRAC Code M3 whereas Inspire Super is a FRAC Code 3/9. Thus, integration of multi-site modes of action for both products was also established as an effective anti-resistance strategy. Ziram and Inspire Super were also submitted for section 18 emergency exemptions, which are expected to come into effect during the course of 2020. The availability of these two fungicides in olive will improve control of Neofabraea and Phlyctema leaf and shoot lesions and will allow for management of fungicide resistance by rotating modes of action.

CIDETRAK® DA MEC™ contains a novel, patented kairomone in a micro-encapsulated liquid formulation that influences the behavior of adult and larval Codling Moth, resulting in significant enhancement of the control of Codling Moth larvae when tank mixed with various insecticides. Additionally, Codling Moth adult control is significantly enhanced when mixed indirectly with airborne Codling Moth pheromone applied as a mating disruption treatment. • What it does: Disrupts oviposition. Changes larval behavior: Stops/delays locating walnut; stops/delays walnut entry and reduces damage. • How to use it: Simply tank mix with each insecticide application. • Longevity: More than 14 days following application. ®

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