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WEST COAST NUT July 2017 Issue SPOTLIGHT: Dust Control Using these 6 Steps Can Help Control Soil Erosion, Mite Control & Safety Issues

In This Issue:

IPM Updates and Summer Considerations Pistachio Nut Phenology 2017 Floods - After the Waters Recede:

Impact Continues for Walnut and Almond Farmers

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Publisher: Jason Scott Email: [email protected] Editor: Kathy Coatney Email: [email protected] IN THIS ISSUE Design Department Email: [email protected] Tel: 559.352.4456 Fax: 559.472.3113 IPM Updates and Summer Considerations Web: www.wcngg.com 4

Contributing Writers & Industry Support Almond Pest ID Workshops: Amy Wolf, MPPA, CFRE, Lu Zhan 10 Provide Sustainability Tools for Almond Growers President and CEO, AgSafe Post-doctoral researcher, UC Davis. Astrid Volder Pistachio Nut Phenology: Plant Sciences, UC Davis Marni Katz 16 California Studies Address Crop Development Contributing Writer Bruce Lampinen UCCE Walnut Specialist, UC Mohammad Yaghmour Davis Area Orchard Systems 20 6 Steps to Effective Dust Control Advisor, Kern Co Elizabeth Fichtner UCANR Advisor, Tulare Narges Moosavi Micropropagation of Hazelnut: and Kings Cos; Mahvelati, Jr. 24 Specialist, UC Davis The Opportunities, Challenges and Limitations Emily J. Symmes and UC ANR IPM Advisor UCCE and AB 1732: Statewide IPM Program Priscilla Rodriguez 28 Safety Specialist, Western Single-User Restrooms and the Impact on Ag Production Greg Browne Ag. Processors Association USDA Plant Pathologist Flooded Orchard Damage Update: Roger A. Isom Janine Hasey 30 President/CEO, Western Recent Study Provides Potential Resources Available UCCE Farm Advisor Ag. Processors Association Sutter/Yuba/Colusa Cos. 2017 Flood - Long After Flood Water Recedes: Sabrina Hill Louise Ferguson Contributing Writer 36 The Impact Continues for Walnut and Almond Growers CE Specialist, UC Davis UC Cooperative Extension Advisory Board 40 SGMA's Will Change the Way We Farm David Doll UCCE Farm Advisor, Merced County Elizabeth Fichtner 1000 Cankers Disease: UCCE Farm Advisor, Tulare County 44 Everything You Need to Know For Walnuts Dani Lightle UCCE Orchards Advisor, Glenn/Butte/Tehama Counties Franz Niederholzer 48 Nutrient Management of Zinc in Pistachios UCCE Farm Advisor, Colusa/Sutter/Yuba Counties

The articles, research, industry updates, company profiles, and advertisements in this publication are the professional opinions of writers and advertisers. West Coast Nut does not assume any responsibility for the opinions given in the publication. View our ePublication on the web at www.wcngg.com

FEATURED ARTICLE

Good, thorough dust control has many benefits from reducing topsoil erosion, to mite control, to safety. Dust control is not just at harvest. It goes through the entire season, according to David Doll, University of California Cooperative Extension (UCCE) farm advisor for Merced County.

See the full story on page 20 Coatney Kathy courtesy: Photo

West Coast Nut July 2017 www.wcngg.com 3 Photo 1: Adult frosted scale on walnut. Photo credit: E.J. Symmes IPM Updates and Summer Considerations

By Emily J. Symmes in the orchard. All of this information there are plenty of blighted nuts in Sacramento Valley Area IPM Advisor will help to make decisions on the need many orchards to serve as early-season University of California Cooperative to treat codling moth for the remainder NOW development sites. Couple this Extension and Statewide IPM Program of the season. with a high codling moth year, and the potential for NOW damage in walnuts Walnuts Although wet winters can cause remains high, in spite of any help with increased overwintering mortality of overwintering mortality that the winter The first codling moth flight this navel orangeworm, significant survival rains provided. Placing traps in the year (1A and 1B peaks) were reported was apparent in walnut mummies ex- orchard (pheromone, kairomone, and/ to be quite high in many orchards, and amined this spring (March 2017). Bear or egg traps) is worth the time invested applications targeting one or both of in mind neighboring orchards may not and can give you a sense of NOW activ- these flight peaks were common. Keep have been able to execute their normal ity and relative abundance. in mind that a good codling moth pro- NOW sanitation programs last winter gram can help minimize early-season either, and these may be a source of Significant populations of frost- navel orangeworm (NOW) infestation, immigrating populations as the season ed scale were evident in a number of thus limiting in-house build-up of progresses (in addition to any car- orchards this year (Photo 1). It is not NOW and reducing the numbers that ry-over populations that may have built entirely clear why this pest, which it will be looking to lay eggs on walnuts up within the orchard). Prior to husk typically present only at low levels, has at husk split. Keep a close eye on trap split, NOW will go back into mummies increased so dramatically in recent counts going into the second and third and into this-season’s damaged nuts years. Research is underway examining flights, numbers of codling moth-in- (codling moth-infested and blighted this phenomenon, as well as best prac- fested dropped nuts, and canopy strikes nuts). With all of the spring rainfall, tices and timings for effective popula-

4 West Coast Nut July 2017 Photo 2: Frosted scale crawlers and adults on walnut. Photo credit: E.J. Symmes

IPM Updates and Summer Considerations tion reduction. Frosted scale produces scale (either dormant/delayed-dor- honeydew when feeding (walnut scale mant or crawler), monitor the popula- does not). This favors growth of sooty tions during the next dormant period mold, which increases the chances for looking for the overwintering nymphs sunburn damage, so keep an eye on this (Photo 3, page 6). Frosted scale has if the orchard was heavily impacted by only one generation per year, so the frosted scale this spring. Frequent rains effects of this season’s spray program throughout winter and early spring will be best observed at this time, and limited the ability for many growers to as next spring’s populations begin to get into the orchards to apply dormant/ develop. delayed-dormant scale treatments, necessitating applications targeting the Walnut husk fly (WHF) trap catches spring crawler stage. Crawler emer- began the week of June 5 in the Sac- gence was observed late in the second ramento Valley. Remember that WHF week of May 2017 (compared to the treatment decisions should be made on first week of May 2015 and last week of a site-specific basis and take the time April 2016), with peak crawler activity to hang traps high in the tree canopy— noted approximately two weeks later this will provide better accuracy in de- (Photo 2). This highlights the impor- tecting activity. If trapping indicates the tance of monitoring the populations, presence of treatable WHF populations, rather than applying treatments based all insecticides should be applied with a on “typical” calendar timing (which bait (i.e., molasses, Nu-Lure®, Monterey would have been too early this year Insect Bait®). The exception is GF-120 to target peak crawler activity). Our which contains its own bait. For low-to research trials this year are exam- moderate-populations, coverage is not ining efficacy of different treatment critical and low-volume and/or partial materials and timings specifically for coverage applications (e.g., alternate frosted scale (walnut scale has been row) of bait with insecticide can be the focus of research in recent years). If treatments were applied for frosted Continued on Page 6

www.wcngg.com 5 Continued from Page 5 effective. However, in high population orchards with extensive previous damage, high-volume, full coverage, and/ or multiple applications of bait with insecticide may be necessary to achieve adequate control. If you miss a timing and are observing fresh stings, full cover neonicotinoids that have some ovicidal (egg-killing) activity mixed with an adulticide will provide partial control of eggs if applied immediately after stings are observed. Generally, a short-residual insecticide-plus-attrac- tant will kill walnut husk fly for 10 days. With the egg development period added to this time, there is about 3 weeks Photo 3. Overwintering frosted scale nymphs. of protection after an application (GF- Photo credit: University of California Statewide 120 treatments often must be applied IPM Program/Jack Kelly Clark more frequently).

Spider mite activity in walnuts re- economically-viable in most walnut just spider mite numbers alone) to mains low as I write this but will likely orchard situations. Treatments should achieve a balance in which predators begin to pick up soon with sustained be based on thresholds of spider mites can provide free control services. Also warmer temperatures. Prophylactic and their natural enemies (particularly consider the impacts of other pesticides May applications of abamectin, while predator mites and sixspotted thrips). on spider mite and predator popula- still favored by many almond produc- In general, the goal is to manage the tions (organophosphates and pyre- ers, have shown to be less effective and ratio of predators-to-spider mites (not throids are highly detrimental to spider

6 West Coast Nut July 2017 mite natural enemies and often result in spider mite flare-ups). More information on treatment thresholds for mites and predators in walnuts is available at: ipm.ucanr.edu/PMG/ r881400111.html and a detailed article on monitoring and management of spider mites in walnuts was published in the May 2017 issue of West Coast Nut. Best practices for getting the most out of your miticide in walnuts include choosing the right material for the job (i.e., those softer on predators if they are present, desired residual activity and pre-harvest intervals, quick and effective knock-down if needed, etc.) and obtaining optimal coverage (high volume, slow speed).

Almonds

As mentioned for walnuts, wet winters can help in the fight against navel orangeworm but make sanitation efforts much more difficult to achieve. Wet weather can help but will provide the most benefit if almonds are on the orchard floor prior to the bulk of the rainfall. A greater number of orchards were not sanitized this past winter, either due to weather-related access issues, or the practice was considered unnecessary because of all the precipi- tation.

In these orchards, where many mummies remained in the tree canopy through spring, there is no shortage of viable mummies for early generations of NOW to oviposit on and develop in (Photo 4, page 8), leading to potential build-up of populations as hullsplit approaches. Remember that even if your orchard is fairly “clean,” NOW can migrate in from nearby orchards (up to a quarter mile). Continue monitoring populations and crop phenology to time any hullsplit applications. Along with sanitation (whenever possible) and insecticide applications, early, rapid harvest and timely removal of nuts from the orchard are the other keys necessary to minimize NOW damage.

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www.wcngg.com 7 Continued from Page 7

Maximize your spray efficacy by using higher volume applications (150-200 gpa) and maintaining slow ground speeds (do not exceed 2 mph).

Many almond growers in the state have adopted the prophylactic approach to spider mite management (early abamectin sprays, typically in May). If you treated your almond orchard in May this year with abamectin, UCCE Farm Advisor Franz Niederholzer wrote a recent blog post on how to follow up with the rest of the season’s mite management (sacvalleyorchards. com/almonds/insects-mites/what-to- if-you-applied-abamectin-to-almonds- Photo 4: in-may/). While the prophylactic approach Almond mum- can be an effective method, there are some my infested with first drawbacks, particularly the impacts to beneficial generation navel predators. orangeworm in spring. Early season destruction of natural enemies and/or their food Photo credit: E. J. Symmes sources will likely mean that they will not be present, or not present in enough numbers at the right time, to provide mea- surable impacts later in the season when we need them to help fight flare-ups.

An alternative is to use a threshold and conservation biolog- ical-control based method of determining treatment timing(s) and materials selection. Admittedly, predators alone may not be sufficient to keep spider mites below economically-dam- aging levels, and miticides may be needed based on your site-specific monitoring when thresholds are reached. Know which predators are present and choose materials accordingly. Using a miticide that is gentle on beneficials helps keep them around to suppress spider mites missed by the pesticide. This link contains a table of almond pesticides and their impact on beneficials, including predatory mites and sixspotted thrips: ipm.ucanr.edu/PMG/r3900311.html.

Employ best practices for getting the most out of your threshold-based miticide application: choose the right material for the job (i.e., those softer on predators if they are present, desired residual activity and pre-harvest intervals, quick and effective knock-down if needed, etc.), obtain optimal coverage (high volume, slow speed), and apply with oil to maximize efficacy. A detailed article using this approach to monitoring and management of spider mites in almonds was published in the May 2017 issue of West Coast Nut.

Comments about this article? We want to hear from you. Feel free to email us at [email protected]

8 West Coast Nut July 2017

Almond Pest ID Workshops: Provide Sustainability Tools for AlmondGrowers

By Marni Katz, Contributing Writer

lmond Board of California’s Califor- Ania Almond Sustainability Pro- gram (CASP) held a series of three pest identification workshops throughout the Central Valley designed to encourage Rijal largely focused on monitoring monitoring, identification and sustain- and control strategies for spider mites, able management of regional pests. ants and navel orangeworm.

In Ripon, California, fourth-genera- Monitoring during the summer tion grower Matt Visser, who farms 60 through harvest is essential for spider acres of almonds with his brother Patrick mite control to preserve beneficials and at Visser Family Farms, welcomed nearly maintain balance for natural predation. two dozen growers, farm managers and others into his orchard to hear the latest. Monitoring should focus on areas of Jhalendra Rijal, IPM Farm Advisor for the orchard that are more prone to mites, Stanislaus County, noted that stink bugs such as edges, drier areas and weaker are also becoming an increasing concern trees. in the area. The University of California IPM “While it is not common, we are program recommends a presence/ab- finding stink bugs in ag areas for the first sence sampling method based on the time,” he said. percent of leaves sampled. Check 75

10 West Coast Nut July 2017 leaves in the orchard using a hand southern fire ants, pavement ants and the er, to prevent NOW larvae from over- lens, inspecting both sides of the less common thief ants, and distinguish wintering inside mummy nuts, remains leaves for eggs or live mites and the them from native gray ants. The main an essential first step in control. presence of predators. distinguishing characteristic of the pest ant species is two humps between the Mating disruption works by confus- If up to 50 percent of leaves abdomen and the thorax. Native gray ing male moths as they emerge looking sampled have mites or eggs present ants have only one hump. Fire ants have to reproduce. The first generation emerg- but there are also predators, such as an amber colored head and thorax and es from April to May, looking to lay eggs predator mites, thrips or beetles, it is black abdomen. in mummies, and the second generation OK to wait to treat. If no predators emerges in late June and July to lay eggs are present, but more than 30 percent Distinct differences can also be seen in split nuts. of leaves have mites it’s best to treat. in ant mounds to help determine if they are a pest species in almonds. Pest Egg traps in spring are an important Rijal said it is important to rotate species typically have multiple mound monitoring tool for navel orangeworm. among classes of chemistry and use openings. By checking weekly to determine biofix each class only once per season to based on the presence of eggs, almond slow the development of resistance. While there are few monitoring tools growers can time controls based on heat for ants, pest identification should be units after biofix. The UC no longer "We have about a dozen effective determined at five different locations recommends once conventional May miticides so we have plenty to chose in the orchard (examining about 1,000 sprays and instead recommends hull from," he said. square feet per location.) The number of split sprays based on 1,200 degree days mounds and level of nut damage should after biofix. Abamectin is good for early help determine if treatment is necessary. season control because its translam- Bait treatments are the best option to “It’s important to time it right, because inar activity works well on younger target the brood and queen that often if you don’t time sprays based on degree leaves. For contact miticides, good remain underground. Early treatment days, you could miss them altogether,” spray coverage is important to ensure with insect growth regulators work well Rijal said. contact with pests. early in the season but take time to work and should be applied three to four Rijal said newly available mating Rijal also helped growers iden- weeks before harvest. For later applica- disruption puffers and adult lures show tify pest ants in almonds, including tions, faster acting contact insecticides promise for commercial management work within about a week of NOW. Researchers are still working but must be timed around to determine how best to relate adult irrigation. pheromone lures to management.

In addition, growers “We are doing that work now in Left (cover photo): can help reduce damage almonds to provide an idea about how to Cliff Ohmart to almonds by minimiz- treat,” he said. “But mating disruption is of SureHarvest ing the amount of time effective for NOW, although it’s relatively guided almond harvested nuts lay on the new and expensive.” growers through ground. the California He said an integrated program that Almond “Even reducing by 1 to includes winter sanitation, mating dis- Sustainability 2 days can really mini- ruption and insecticides at hull split, as Program. mize the chance of ant needed, are likely to become the industry damage to the nuts,” Rijal norm. said. “My feeling is that this Left : UC IPM Navel orangeworm technique will eventually Advisor Jhalendra remains one of the biggest become a standard Rijal helps growers insect pests in almonds, practice used by growers identify and though pressures vary in California.” manage key pests. from orchard to orchard. Rijal said mating dis- Mating disruption works to confuse ruption, while still new, males and prevent them from repro- is likely to be the next ducing with the female. The techniques frontier in managing na- have been used successfully in pears and vel orangeworm (NOW). Winter sanitation, howev- Continued on Page 12

www.wcngg.com 11 Left: Ripon almond grower Matt Visser shares information about his 60-acre almond orchard.

Right: UC IPM Advisor Jhalendra Rijal helps growers identify and manage key pests. Almond Pest IDWorkshops Continued from Page 11 Rijal recommends installing one to mating disruption can be impacted by other crops for years, but it is a newly two puffers per acre in spring, targeting topography—the more uniform, the developed concept in almonds. the top third of the tree. The success of more effective. Wind direction is also a

12 West Coast Nut July 2017 convert required orchard profile infor- growers using the CASP platform, now, mation into a Nitrogen Management and it is quite user friendly,” Ohmart Plan report required by the Irrigated said. “It’s designed with all the informa- Lands Regulatory Program. The irri- tion you need to manage in your orchard gation calculator is a popular tool for in an easy way. It’s all there in one spot so those who haven’t invested in complex you can come back to it year after year.” irrigation monitoring and reporting systems. It uses the latest UC research and For more information on the Califor- recommends the amount and timing of nia Almond Sustainability Program visit water to be applied based on local evapo- www.almonds.com/growers/sustainability. transpiration (ET) data pulled from the nearest CIMIS station. Comments about this article? We want to hear from you. Feel free to “We have more than 1,000 almond email us at [email protected]

factor. With high pest pressures, puffers can be used in conjunction with insecticides, particularly on border areas, to keep populations down.

The CASP Pest ID workshops provided practical tips for integrating sustainable pest identification and management practices in the orchard and also explained sustainability tools available to almond growers in California. Almond Board of California’s Jenny Nicolau noted that CASP helps provide collective information about how almonds are farmed sustainably in California to meet the growing demand for such information from food man- ufacturers, retailers and consumers of California Almonds.

Cliff Ohmart with SureHarvest, which has worked since 2009 with the Al- mond Board to develop its sustainability program, guided growers through the process of establishing an online CASP account and shared some of the added value tools available to growers who participate in the program. He noted that the program is voluntary and individual data is secure and confidential.

Online tools like the nitrogen calculator help growers manage inputs and can

www.wcngg.com 13

Pistachio nut phenology: CAlifornia studies address crop development as a function of

By Elizabeth Fichtner, UCANR Advisor, Tulare and Kings Cos; heat unit accumulation Louise Ferguson, CE Specialist, UC Davis, Narges Moosavi Mahvelati, Jr. ,Specialist, UC Davis and UC ANR; Lu Zhang, Post-doctoral researcher, UC Davis. microclimates in which pistachios are alifornia pistachio growers have limitations of modeling anticipated planted, and are subject to influence Clikely noticed the influence of the crop development based on calendar from large-scale trends such as glob- cool 2017 spring on crop develop- date. Nut development trends will also al climate change. As a consequence, ment. This observation illustrates the vary based on geographic area or local scientists utilize alternate methods to define developmental growth stages as a function of heat unit accumulation. This allows for comparisons of crop development between cultivars across sites, years, and even decades. Thermal unit modeling may also be used to fa- cilitate pest control, irrigation schedul- ing, and prediction of harvest time.

Some variability may exist between various model types; however, the unifying concept is that they strive to correlate milestones of plant development with accumulated heat. The time of fruit set is a biofix at which thermal unit (TU) accumulation is equal to zero. Heat unit measurements are determined by tracking hourly data using data loggers installed in the field. Thermal units are calculated by taking a daily average temperature and subtract- ing the base temperature threshold. In pistachio models, 7˚C is utilized to indicate the base temperature beneath which growth does not occur. The work of Allan et al. 2014, focused on relating six variables (nut length, width, height, volume, penetrability, embryo size) to

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16 West Coast Nut July 2017

Continued from Page 16 accumulated heat in each of 5 cultivars of pistachio.

Pistachio nut development is defined in three overlapping stages. Stage 1 is defined by the growth of the pericarp to its final size; stage 2 is defined by the hardening of the endocarp (ie. shell); stage 3 is character- ized by growth of the embryo (Figure 1). In pistachio, Stages 1 and 2 and Stages 2 and 3 have overlapping curves, indicating that portions of these developmental phases occur simultane- ously (Allan et al 2014). Stages 1 and 3, however, are mutually exclusive of each other such that the pericarp is fully formed before embryo development is initiated (Figure 1). The final volume of the pericarp is achieved after accumulation of approximately 670 TU (Fig- ure 2). In 2016, this would

18 West Coast Nut July 2017 development of a model that predicts the number of heat units to complete all three growth stages in the Kerman, Lost Hills, Golden Hills, Kaleghouchi and Pete1 cultivars and to develop the software to convert calendar dates to thermal units based on historical temperature records and two weeks weather forecast. Growers will be able to predict optimal harvest date con- veniently by logging into our website and inputting the location, cultivar and blooming date.

Select References Allan, C.A., Ferguson, L., Bourgeois, G., Cristosto, C., Thur, K., Ramacho, F.A., Jiminez, F.J., Saracoglu, T. Pista- chio nut phenology and development in five cultivars as a function of heat units. Report to the California Pistachio Research Board. www.calpistachiore- search.org.

Comments about this article? We want to hear from you. Feel free to email us at [email protected] have occurred around the beginning of June in the southern San Joaquin Valley (SSJV). Stage 2, the process of shell hardening, requires approximately 2423 TU. Embryo growth (Stage 3) is initiated after around 900-1000 TU accumulated (mid-June in 2016; SSJV) and maximum embryo length requires approximately 1880 TU (mid-August in 2016; SSJV). Stage 2 requires more heat units for completion then Stage 3. The variability of these mean values is largely contributed by differences in cultivars.

This year, we are building the pistachio nut growth models and strengthening the prediction ability of the model by continuing weekly fruit sampling from early fruit set to harvest. In addition to current equation of TU accumulation, we are also improving the method of calculating heat units using Asymmetric Curvilinear Growth Degree Hours (GDH) Model, as well as to predict the base, optimum and critical temperatures for pistachio growth in California. Our final objective is

www.wcngg.com 19 Photos credit: Kathy Coatney

Steps to Effective Dust Control 6 By Kathy Coatney, Editor ood, thorough dust control has “Nobody wants to be throwing dust out something to think about. Gmany benefits from reducing top- in the road and risking collisions out soil erosion, to mite control, to safety. on the county roads Growers should be thinking about Dust control is not just at harvest. It and highways,” who and what are around when goes through the entire season, accord- Niederholzer they’re harvesting, Ludwig said. ing to David Doll, University of Cali- said, add- Also, be mindful of nearby fornia Cooperative Extension (UCCE) ing dusty roadways, neighbors, other farm advisor for Merced County. orchard crops with crews working, roads and consider what you as “I think many people focus at can a grower can do to try and harvest because of how much dust you also be minimize dust, particular- throw out just through the harvesting a haz- ly in those situations, she process,” Doll said, but if good prac- ard to added. tices are employed earlier, it will also work- reduce dust at harvest, which is better ers and If harvesting near a busy for the trees. Franz Niederholzer, UCCE impact road, consider placing traffic farm advisor for Colusa, Yuba, and visibility. signs to warn motorists of har- Sutter Counties, said, dust control is an vest activities. environmental, safety and even a pest Doll agreed control issue. safety is another factor, MAINTAINING and a good reason for dust control. 2 ORCHARD ROADS 1 SAFETY Gabriele Ludwig, director of sustainability and environmental affairs for the Maintaining orchard roads with wa- Dust is kind of like spray drift when Almond Board of California, said, as ter, oil and different salt solutions will it’s close to roadways, Niederholzer said. acreage has grown, the visibility is really help reduce dust, Doll said.

20 West Coast Nut July 2017 Scott Hunter, part of Hunter Farms through the orchard when soils are wet EQUIPMENT in Livingston, California, does dust to prevent ruts from forming. Ruts 5 CALIBRATION control on his orchard roads and there have to be graded prior to harvest, and are several dust reducing agents avail- grading creates more dust, he said. Equipment calibration is a critical able, he said. Cover crops can reduce compaction component to dust control, Doll said. and dust. While cover cropping is not Don’t set the heads any lower than “We use a product called Dust-Off, necessarily convenient with other prac- necessary. Wire tines can be set as high which is actually food grade. It’s a good tices, it does help reduce compaction as 0.5 inches off the ground and still do product,” Hunter said. and dust in the field, Doll said. a good job sweeping. If they are set too low, the sweeping head will move an Some growers are using magnesium Driving on a bare orchard floor will excess amount of dirt into the windrow chloride for dust control on orchard kick up more dust than an orchard and substantially increase dust from the roads, Niederholzer said. with a cover crop. But at harvest, cover pickup machine. Using wire tines on crops can be a struggle and a challenge sweeper heads without rubber flaps will “Some materials are latchkey where to manage, according to Doll. also help reduce dust. there’s an applicator that comes and applies the product,” Niederholzer said, and others just use water. Continued on Page 22

“Dust control on roads is also part of a mite management program, and everybody wants to keep mites under control. So, keeping dust under control is double duty. Dusty trees tend to be where mites show up first,” Niederholzer said.

Steps to Effective 3 MITES “The dust that we create in an orchard is just going Dust Control to consolidate, it’s going to settle on the trees and eventually continue to build. And when a tree becomes dusty, it becomes stressed, and the stress brings in mites,” Doll said.

Mite damage has what Doll calls a hangover effect.

“It doesn’t necessarily impact this year’s crop as much as it can impact next year’s crop because you’re defoliating the trees and then the tree will release, and when it releases, it reduces the number of buds that will develop into fruit buds for the next year,” Doll said, adding dust control is one method for con- trolling mites. Photos credit: Kathy Coatney ORCHARD FLOOR 4 MANAGEMENT

Good dust control practices also help prevent problems with erosion, Doll said.

“I’ve been in more and more orchards where you’re seeing the berm that people plant the trees on has been eroded over time. And that erosion is usually due to the harvesting practices—the multiple times they’re sweeping, the multiple times they’re picking up in these orchards,” Doll said.

Reducing compaction is an important way to reduce dust. Doll advises growers to avoid driving Continued from Page 21 the berms, you’re able to go much faster, There is new equipment available which would equate to much less dust,” that is more effective for managing dust “You don’t want to go too deep in Hunter said. at harvest, Doll said. harvesting,” Hunter said, adding when you’re sweeping, you don’t want to go Hunter does about 50 percent of his Ludwig agreed investing in new too slow either. harvesting at night. Harvesting at night equipment that’s been engineered to re- means there’s generally less wind to duce dust is another way to reduce dust. Good orchard practices and having a move the dirt, and it settles back down, There are two ways to do this, Ludwig good orchard floor is probably going to he said. continued. One way is to actually go be the biggest thing that you can do to out and buy reduced dust equipment, or reduce the dust because it allows you Ludwig also suggested two, use the EQUIP program through to go through the field faster, using the trees to cap- United States Department of Agri- Hunter said. ture some of the dust culture (USDA)/National Resources “It’s like you’re in a car. If “It helps us, too, by blowing into the Conservation Service (NRCS). you’re getting from point A orchard instead of to point B without traffic, to schedule people. out. Eligible equipment is limited to you’re probably going to There’s a lot of benefits specific harvesters from demonstration have less emissions than if Plan passes trials at Texas A&M that were found to you were sitting in traffic to doing it at night,” and travel direc- reduce particulate matter by at least 30 for an extra hour,” Hunter Hunter said tion so that dust is percent. said. directed away from This isn’t a cost share program for roads, homes and directly buying equipment, Ludwig said. “If you can go through the sensitive locations like Instead, qualified growers will receive field at a good pace, and get a large schools, hospitals and day- $10.52 per acre for up to three years for percentage of the almonds without care centers, Ludwig said. use of qualified harvesters. having to go back and slow down, and have to really sit there and turn the 6 NEW EQUIPMENT “Part of the reason they did that is blower up all the way, and blow around there is quite a bit of custom harvesting

22 West Coast Nut July 2017 going on. So, this allows a grower who’s not doing his or her own harvesting to choose to work with a custom harvester who has low dust equipment, and then get some funding from NRCS,” Ludwig said, adding it also encourages custom harvesters to invest in the reduced dust equipment.

Applications are accepted year- round through your local NRCS office. Growers considering this for the current year’s harvest should contact their local office as soon as possible.

For more information on dust control, go to www.almonds.com click on grower, then harvest.

Comments about this article? We want to hear from you. Feel free to email us at [email protected]

www.wcngg.com 23 Micropropagation of Hazelnut: The Opportunities, Challenges A Limitations

By Kathy Coatney, Editor make us money, but they’re going to be Ron Chapin is a hazelnut grower, out of production in the next five years astern filbert blight (EFB) is a and he works with his two sons and totally,” Chapin said. Efungus that has infected hazelnut three nephews. The family run farm orchards throughout the Pacific North- has a total of six families involved in the There are another 50 acres of mature west. EFB causes severe cankering operation in Gervais, Oregon. Lewis, which are holding their own with and branch dieback. The only way to the blight. We also have 60 acres of Jef- control the disease is by pruning back Chapin said they have roughly 250 ferson, a blight-resistant variety, which infected limbs. For severely infected acres of the Ennis variety that are rapid- are just coming into good production. trees, removal may be the best option, ly dying of the disease. Another 280 acres of Jefferson are third especially with susceptible varieties like leaf or less, Chapin said. Ennis or Daviana, and replace them “They’re very hard to look at these with blight-resistant varieties. days to tell you the truth. They still During this period where they are waiting for the new blight-resistant varieties to come into production, Chapin is counting pretty heavily on the Top: Attendees nursery end of their business to actually listening to Ron Chapin provide income until the acreage gets demonstrate, Hazelnut on track. Summer Tour Micropropagation Left: Plants that have Chapin has been using microprop- been micropropagated agation where tissue is taken from a by Ron Chapin in Ger- plant and grown in a laboratory to vais, Oregon. produce plantlets that are genetically identical to the parent. Photo courtesy: Kathy Coatney “We’ve been developing microprop-

24 West Coast Nut July 2017 agation here for a number of years Chapin experimented growing the because it’s a way of mass producing Jefferson variety in 15 gallon pots. “I our plants,” Chapin said. just threw them in pots, and I found that in two years I could grow a pretty “I’ve worked over the years with nice looking tree in a 15 gallon pot,” he grafting, and with layering, and all of said. the various other methods with vary- ing degrees of success,” Chapin said. “We planted out small numbers with “There’s no other method where we can it, and finally last year, we planted out get the numbers that you can with the 40 acres,” Chapin said. He was very micropropagation.” impressed with the trees.

“It’s (micropropagation) an amazing “I think I truly can take two years process. You can get through about off the time to putting the orchard into eight to nine cycles a year, and multiply production by that method,” Chapin by a factor of three or four each time, said. and you can get one plant to several thousand by the end of the year,” Chap- Initially Chapin thought it would in said, adding it’s a way of very rapidly put them three years ahead by using the Above: Plant samples getting your numbers up. potted trees, but he found they lost a year due to the transplant shock. Left: Ron Chapin, a hazelnut grower speaks “I’m really a hazelnut grower far about micropropagation of hazelnut trees. more than a micropropagator,” Chapin While Chapin has seen good results, said, "But we needed access to the new he doesn’t think it’s practical to ship in varieties, so that was my main interest 15 gallon pots by truck. It took several Photos courtesy: Kathy Coatney in doing micropropagation." loads just to plant one acre of trees this year, Chapin said. Initially, the micropropagation This is staggering cost for the grower, started with a few thousand plants a “But it’s fun to look at, and I need to but after taking into account ground year. Today, it’s grown to about 150,000 understand it, to understand the pro- costs for two years, Chapin thinks it plants a year, Chapin said. cess to tell other people how to do it,” might be worth it. It’s an expensive Chapin said, plus it’s also expensive. process, but there could be ways to do it "Every year we use about 40 percent cheaper as an industry, Chapin said. of the 150,000 we produce annually," Chapin said. "The other 60 percent is “We’ve got a good industry that sold to other nurserymen to sell to the innovates a lot,” Chapin said. industry, plus we also do a major business in bare-root tie-offs." Pitfalls to Micropropagation “We’re going to be Potted Plants There are definitely pitfalls to micro- looking at $30 or propagation, Chapin said.

so for that plant,” “Most of us that have worked with micropropagated stuff have had some Chapin said. real colossal disasters. There’s been times that we’ve just killed off really major groups of plants, and then there’s a lot of times, too, you get some really just beautiful stuff out. But it’s not for everybody,” Chapin said.

“Once a plant comes out of micropropagation, it goes into our rooting facility, and we take it through a process. It’s kind of like detoxing somebody that’s been on drugs. Every day we stress it just a little harder. We lower the

Continued on Page 26

www.wcngg.com 25 Continued from Page 25 hormone levels, and you get back to a When plants are micropropagated plant that really likes to grow extremely humidity a little bit. We increase the and come out of the micropropagation, vigorously,” Chapin said. light a little bit. We try to get it actively they are used to 16 hour days, Chapin growing and putting on fresh leaves, said. “The trick to growing them is you get and then we take it clear out of there,” them growing hard, and you keep them Chapin said. “You bring them out in growing hard, and then you get a great the springtime, in March plant,” Chapin said. The plants are grown for a short period of time in a greenhouse to put on more or something like that, “But if you let them stagger, they growth and get them climatized to a they see about a 12 hour don’t have the reserves and everything little harder conditions before they go day and that just that a normal plant does, and you can to another nurseryman’s greenhouse, triggers them to go to get them in kind of this stupor where Chapin said. sleep,” Chapin said. they don’t know which way is up, and it’s hard to break them out of it,” Chapin “There’s a lot of things that happen in said. micropropagation,” Chapin continued. “With micropropagated plants, they There are a lot of things that can Some plants come out of micropropaga- have a lot of extra vigor—it’s some- go wrong, Chapin said. “Anytime that tion that are growing well while others thing we call juvenility,” Chapin said, a you’re growing in a greenhouse, there’s may come out yellow and do not do term that no one in the industry likes a lot of ways to kill a plant and do it well, Chapin said. because it’s kind of a catchall. quick,” Chapin said.

Some will go into dormancy. There’s “Juvenility would be like a newly Micropropagation is not for the faint nothing that can be done to make it sprouted plant, and you kind of re- of heart, Chapin said. grow except maybe a hormone shot vive that when you run it through the Comments about this article? to make it wake up, and hopefully put micropropagation process—you do We want to hear from you. Feel free to another eight to 12 inches of growth on the rapid generations, you do the high email us at [email protected] it, Chapin said.

26 West Coast Nut July 2017

AB 1732: Single-User Restrooms and the Impact on Production

Agriculture

By Amy Wolf, MPPA, CFRE President and CEO, AgSafe

n 2016, the legislature and governor toilet) and one urinal with a locking • Where there are less than five Ibrought to fruition Assembly Bill (AB) mechanism controlled by the user. Ac- employees, separate toilet rooms for 1732: Single-User Restrooms. The law cording to the Division of Occupational each sex are not required provided changed the California Health and Safety Safety and Health (Cal/OSHA), chemi- toilet rooms can be locked from the Code Section 118600 and took effect cal/non-flush toilets are not included in inside and contain at least one water on March 1, 2017. At it’s core, the law the “single-user toiler facility” definition. closet. requires all single-user toilet facilities As such, portable restrooms common- in any business establishment, place of ly used in production agriculture are • Urinals may be installed instead of public accommodation, or state or local exempt from the law. water closets in toilet rooms to be government agency be identified as used only by men provided that the all-gender toilet facilities by signage that That being the case, the number of number of water closets shall not be complies with Title 24 of the California gender-specific portable restrooms avail- less than two-thirds the minimum Code of Regulations, and designated for able in the field is still dictated under the number of toilet facilities. use by no more than one occupant at a requirements of the California Code of time or for a family assisted use. The law Regulations, Title 8, Section 3457 – Field Exception: An employer may provide is fairly straightforward but it’s imple- Sanitation. The standard specifically transportation to toilet and hand-wash- mentation for production agriculture is states the following: ing facilities, as an alternative means of not nearly as simple. compliance if: • Separate toilet facilities for each sex Impact on Production Agriculture shall be provided for each twenty 1. Employees perform field work for (20) employees or fraction thereof. a period of less than two (2) hours The change to the law includes the (including transportation time to term “single-user toilet facility” which is • One hand-washing facility shall be and from the field), a critical element for production agricul- provided for each twenty (20) em- ture. As of May 6, 2017, the phrase has ployees or fraction thereof. 2. Fewer than five (5) employees in been defined as one water closet (or flush any agricultural establishment are

28 West Coast Nut July 2017 engaged in hand-labor operations Lastly, the definition of “single-user dustries. Since 1991, AgSafe has educat- on any given day, or toilet facility” has yet to be finalized. ed nearly 75,000 employers, supervisors, According to Cal/OSHA Chief Juliann and workers about these critical issues. 3. Employees are not engaged in Sum, the Fair Employment Housing hand-labor operations. Commission (FEHC) recently adopted regulations that define “single-user” as Comments about this article? It is important to remember that flush toilets as well as non-flush toilets. We want to hear from you. Feel free to while chemical/non-flush toilets are Her agency, as well as the FEHC, are cur- email us at [email protected] currently exempt, any single-user flush rently reviewing their interpretations of toilet in an office, shop or processing both laws and are determining the final facility must be labeled gender-neu- definition for the purposes of AB 1732. tral. In addition, employers need to Chief Sum encourages employers to officially communicate with employees visit their website often as their AB 1732 that if they self-identify with a gender Frequently Asked Questions document different from the one on their official will be updated when or if the definition identification provided at the time of changes and chemical/non-flush toilets hire, they are encouraged to share their are no longer exempt: http://www.dir. gender restroom preference. It is critical ca.gov/dosh/toilet-facilities-FAQ.html. to remember that legally you cannot arbitrarily decide an individual’s gen- For more information about AB 1732 der based on appearance, conjecture or or any worker safety, health, human any other information other than the resources, labor relations, or food safety individual self-identifying. You also can issues, please visit www.agsafe.org, call not require employees to self-identify. us at (209) 526-4400 or via email at However, you can encourage self-iden- [email protected]. AgSafe is a 501c3 Under the new law, “single-user” has tification, and once that information is nonprofit providing training, education, been defined as one water closet (or provided, ensure the appropriate number outreach and tools in the areas of safety, flush toilet) and one urinal with a locking of gender-specific portable restrooms are labor relations, food safety and human mechanism controlled by the user. available in the field. resources for the food and farming in-

www.wcngg.com 29 Flooded Orchard Damage Update and Management Considerations

By Janine Hasey, UCCE Farm Advisor, Sutter/Yuba/Colusa Counties Contributing Writers: Greg Browne, USDA Plant Pathologist, UC Davis Astrid Volder, Plant Sciences, UC Davis Bruce Lampinen, UCCE walnut Specialist, UC Davis

n 2017, high and fluctuating water orchards exhibited tree death or chard on heavier soil bloomed and Iflows, unprecedented for their dura- severe decline, but assessing losses started to leaf out, shoots began to tion, passed through the Sacramento should be delayed until the end die (Photo 1). However, some buds and Feather Rivers. Orchards were hurt of summer when the extent of (mainly on larger limbs) tried to by these flows due to direct flooding, damage will be clearer. There may push. Once the soil dried out, the indirect flooding via under-levee seep- also be effects seen next year and trees began to recover (Photo 2). age, and loss of land through river bank subsequent years. This illustrates why it is best to wait erosion. Many orchards had standing and leave trees through the sum- water from January through mid-May. In • Since peach trees start blooming in mer to more fully evaluate poten- other orchards, ditches overflowed with late February and are very sensitive tial recovery. nowhere to pump water out. Unlike pre- to wet conditions, the first peach vious years where floods occurred from tree damage was noticed in late • Preliminary results show Phytoph- levee breaks, such as 1986 and 1997, trees March/early April. Walnut root thora in several locations where we in 2017 had a much longer exposure activity begins in later spring, with sampled surface water. to waterlogged conditions. This article waterlogging symptoms appearing details our observations on flooded or- in early May. • In river bottoms where walnut chard damage as of early June, research trees were partially submerged for plans, management considerations, and • Some peach and walnut trees had prolonged periods, we isolated Phy- an update on potential resources avail- healthy crowns and roots in the tophthora species from bleeding able for flood damaged orchards. For top foot of soil even though they root and aerial trunk cankers first details on flooding damage generalities were leafing out late or had leafed noticed around mid-May (Photos and past flood events, please see our ar- out and died back. These symptoms 3 & 4). ticle in the 2017 spring newsletter issue, were caused by water logging of which can be viewed in 3 parts at www. deeper roots where soils were still • In a young Chandler orchard sacvalleyorchards.com/walnuts. saturated. In previous years, flood- on RX1 rootstock, a third of the ed trees usually had dead crown orchard had seepage from January Thoughts and Observations to Date tissue and rot of shallow roots from to early May, whereby only the tops waterlogging and/or Phytophthora. of the berms were not submerged. • By early June 2017, many flooded Flooded trees leafed out about a or waterlogged walnut and peach • In early April, after a peach or-

Continued on Page 32 30 West Coast Nut July 2017 Photo 1: Peach collapse from waterlogging taken Flooded Orchard April 5, 2017.

Damage Update Photo 2: Same orchard on June 1, 2017 with new shoot and growth after soil dried out. Management 1 2 Considerations

Photos 3 & 4: Bleeding cankers associated with aerial Phytophthora on a river bottom walnut tree (taken on May 23, 2017).

3 4

Photos 5 & 6: Late leaf out of waterlogged Chandler on RX1 rootstock. The tree on the right appears to be recovering as soil dries out 5 (taken on May 23, 2017). Continued from Page 30

month later than those not flooded. Some trees are struggling while others are continuing to leaf out and grow (Photos 5 & 6, page 31).

Research Plans

Our approach is to study two potential problems of concern: 1) diseases caused by Phytophthora and 2) impact of waterlogging on the root system.

• We know the “water mold” Phy- tophthora is found in surface water and infested soils. In May, we sampled water in the Sacramento and Feather Rivers, in swales of standing flood water in the Feather River bottoms (Photo 7), and in seepage water from under levees along both rivers for the presence of Phytophthora.

• We sampled several walnut trees with symptoms of aerial Phytophthora and examined the crown and upper roots on declining trees. We will monitor these sites through the summer and backhoe trees to examine root systems.

• We will study the impact of long- term flooding from continued- seepage on walnut root health and tree water status.

Management Considerations

• Flooded orchards will likely respond to irrigation differently than normal, since root systems are compromised.

• In saturated soils, fine roots die, and depending on the extent of flooding, larger roots can die as well. It takes time for the root system to regain functionality and re-start new fine root production after flooding.

• If the water table level below the soil surface drops gradually, trees Photo 7: Walnut in foreground collapsed in a swale of flood water that we sampled (background) in the river bottom (taken on May 23, 2017). All photos taken by Janine Hasey. Continued on Page 34

32 West Coast Nut July 2017

Continued from Page 32 soil is saturated as the water level • It is not a good idea to prune drops, as well as the amount of or fertilize trees after flooding. may be able to continue to pro- water that is being moved up Pruning will reduce both carbo- duce functional roots at increas- above this level of saturation hydrate reserves and leaf area, ingly deeper levels over time. by capillary rise. Apply enough while fertilizer applications may Initial irrigation could be delayed water to bring the soil to field mostly go to waste and delay or for some time, as deeper roots capacity to enable plant water damage root production. The may maintain water uptake. uptake from the upper soil, but best approach would be to wait, avoid prolonged periods of sat- and let the tree adjust to the • However, if the soil remains uration that may damage roots. altered environmental conditions saturated at some level below It is easy to saturate the soil, while managing irrigation as the surface, the only functional particularly when the water table described above to avoid further roots may be at a very shallow is close, so irrigate judiciously, damage to the root system. depth and irrigation may have to ideally using both soil moisture be initiated earlier than normal. monitoring and plant pressure Potential Resources for Orchards In this case, shorter but more chamber data to aid in deter- Damaged by Flooding frequent irrigations could help mining irrigation duration and avoid further damage to roots in frequency. We still don’t know fully which programs the upper zone. are available and who will qualify for • Do not initiate irrigation until what programs. For more complete sum- • Carefully monitor both soil water pressure chamber measurements maries of the resources available below levels and tree water status so show trees are 2-3 bars below and how to report tree damage visit: that the trees can be gradual- the fully watered baseline (more ly brought back to health. Soil dry) and only irrigate enough to http://www.sacvalleyorchards. based monitoring, using Wa- bring the trees back up to about com/blog/almonds-blog/resourc- termark® soil moisture sensors 0.5 to 1 bar below the baseline by es-for-flooded-orchards/ installed at different depths, will applying short sets of irrigation. let you know the level where the

34 West Coast Nut July 2017 1. Farm Service Agency (FSA) the tax roll, you can obtain a claim future income. There are two work- Contact your local office for form from the Assessor’s office. sheet versions: "With Replanting" program details and deadlines to and "Without Replanting”. qualify. Note that to qualify for FSA 3. Tree loss calculators based on UCCE programs, dead trees from 2017 cost studies through Agricultural & Re- https://coststudies.ucdavis.edu/ flooding/seepage need to be left source Economics at UC Davis. tree-vine-loss/ in orchards for loss assessments When an individual tree or vine is that will be conducted later this destroyed in an orchard or vine- summer. All the programs available yard due to natural causes, vehicle through the FSA can be accessed at accident, shaker damage, or other causes such as flooding, the link be- https://www.fsa.usda.gov/ low provides workbooks on specific Comments about this article? crops to calculate the value of a We want to hear from you. Feel free to Tree Assistance Program (TAP) single tree or vine lost to any cause email us at [email protected] The TAP provides financial assis- taking into account the loss of tance to eligible nursery and tree crop growers to rehabilitate or replant eligible trees or vines lost by natural disasters. To qualify, there must be more than 18 percent (15 percent + normal three percent) mortality loss in an orchard block. Final date to submit an application and supporting documentation is 90 days after the disaster event or the date when the loss is apparent.

https://www.fsa.usda.gov/Assets/ USDA-FSA-Public/usdafiles/ FactSheets/2015/tap_fact_sheet_ oct_2015.pdf

Emergency Loan Assistance A program which provides emergency loans to help cover production and physical losses in counties declared as disaster areas by the President.

Emergency Conservation Program (ECP) Tehama County and Butte County FSA offices are waiting to hear final approval for the Emergency Con- servation Program. This program may help assist with debris removal, releveling or grading, and restor- ing irrigation systems. Contact the respective office if you have land in Butte or Tehama counties. This program will not apply to orchards inside the levees.

2. County Assessor The Revenue and Taxation Code allows reassessment of property damaged by misfortune or calami- ty. If there is at least $10,000 worth of losses of tree value currently on

www.wcngg.com 35 Long After The 2017 Flood Water Receeds - The Impact Continues for Walnut & Almond Growers By Julie R. Johnson Contributors to the article include: Janine Hasey, UCCE Farm Advisor, Sutter/Yuba/Colusa Counties; Greg Browne, USDA Plant Pathologist, UC Davis; Astrid Volder, Plant Sciences, UC Davis; and Bruce Lampinen, UCCE walnut Specialist, UC Davis.

t’s hard to complain about this winter erosion,” reported Janine Hasey, Univer- downstream from the Oroville Reservoir Iand spring’s rainfall amounts as the sity of California Cooperative Extension into the Feather River. When California state recovers from a historic drought, (UCCE) Farm Advisor, Sutter/Yuba/ Department of Water Resources (DWR) but for some farmers living along the Colusa counties, in a research document, authorities sharply reduced water flow Feather River in Northern California, the “Flooded Orchard Damage Update and into the river to enable repair work, rainfall, in combination with the failure Management Considerations.” countless acres of riverbank eroded and of the Oroville Dam spillway, spelled washed away. disaster. Such is a case for Marysville walnut grower Brad Foster, who farms acreage “I’m not the only grower to have “High and fluctuating water flows, surrounding the Marysville area, includ- lost acreage along the river and to have unprecedented for their duration, passed ing 400 acres of walnuts in river-bottom orchards standing in flood waters for through the Sacramento and Feather land adjacent to the Feather River. weeks on end,” said 58-year-old Foster, Rivers in 2017. Orchards were hurt by The riverbank serves as a natural buffer who has been farming for 30 years. “I these flows due to direct flooding, indi- between his orchards and the Feather have neighbors up and down the river rect flooding via under-levee seepage, River. With rainfall and the spillway who have suffered as much, if not more and loss of land through river bank collapse, large amounts of water poured than I have.”

The Crisis

On Feb. 27 the Feather River from Gridley south averaged 89 feet. That was the day DWR engineers temporarily stopped the reservoir flow to make critical repairs to a power plant, according to reports.

In less than two days, the river dropped 15 feet and slowed from 46,000 cubic feet per second to 2,500 cubic feet per second.

Normally, a significant reduction in reservoir outflow from the dam occurs over a period of days. That wasn’t the case in February.

Foster explained the river acts as a support for the riverbanks and when the water recedes quickly it sucks the bank with it.

“You could literally watch acreage washing away,” he added.

36 West Coast Nut July 2017 He described the water saturated wall Call grows walnuts on acreage adja- At this point in time Call doesn’t see of riverbank flowing away as looking cent to the Champlin Slough, a tributary any signs of increase in disease or pests like “applesauce.” Such occurrences are to the Sacramento River. He recorded among his orchards, but he said time will referred to a “sloughing,” when heavy, 33 inches of rain this year, saying the tell. saturated soil is ripped from the river- average for the region is 21 inches. banks by its own weight. Another positive he ran into from the “With a wet winter and spring like we abundant rain was a month’s delay in The Impact Continues for Foster estimates he lost at least five just experienced, either the trees grow needing to start spring irrigation. acres of river bottom land to the erosion. like crazy or they die. As I have traveled Assessing damage to sections of his between here and Sacramento I have “In addition, the amount of rainfall Walnut & Almond Growers orchards had to wait until the water re- seen a lot of damage in orchards and a we experienced has created a reserve of ceded. Foster was then joined by experts lot of dead trees. For me, the majority of moisture in the soil. The rainfall goes in the field, such as Hasey, to study his my trees grew really well, lots of growth, down and water is stored deep in the soil orchards, conduct tests, research and it has overall a very positive year,” Call creating a reserve that will benefit in the assessments. said. summer,” he added.

“What I am seeing now is a lot of However, not everything was incident What Researchers Found black stain on my trees,” Foster said. “I’m free. A problem Call ran into this spring hoping the research will be able to deter- was the delay and difficulty of getting Call and Foster do have one thing in mine what the blackness is and what can into his orchards on a timely basis. common from this year’s generous rain- be done about it.” fall—a cautious outlook when it comes “We didn’t want to compact the wet to the possibility of disease within their In Other Areas ground. It doesn’t come back and that orchards due to extended increase in leads to water sitting on the ground in moisture, and the potential for orchard Fortunately, the rains didn’t result in the future,” he said. “Also, the rains de- and crop losses. a crisis for the majority of growers in layed us in clearing brush out and when Northern California. I couldn’t clear the brush and I couldn’t However, Hasey reported assessing Los Molinos walnut grower Brad Call mow, it delayed spraying herbicide and losses should be delayed until the end of said the rains have been nothing but a blight control.” blessing. Continued on Page 38 Continued from Page 37 infested soils. In May, we sampled water the soil is saturated as the water in the Sacramento and Feather Rivers, level drops, as well as the amount of summer when the extent of damage will in swales of standing flood water in the water that is being moved up above be clearer. In addition, she believes there Feather River bottoms, and in seepage this level of saturation by capillary may also be effects seen into next year water from under levees along both rise. Apply enough water to bring and subsequent years. rivers for the presence of Phytophthora,” the soil to field capacity to enable Hasey said. plant water uptake from the upper “Many orchards had standing wa- soil, but avoid prolonged periods of ter from January through mid-May. In The team also sampled several walnut saturation that may damage roots. other orchards, ditches overflowed with trees with symptoms of aerial Phytoph- It is easy to saturate the soil, partic- nowhere to pump water out. Unlike pre- thora and examined the crown and ularly when the water table is close, vious years where floods occurred from upper roots on declining trees. so irrigate judiciously, ideally using levee breaks, such as 1986 and 1997, trees both soil moisture monitoring and in 2017 had a much longer exposure to Continued study of both issues will go plant pressure chamber data to aid waterlogged conditions,” Hasey said. on throughout the summer and into an in determining irrigation duration extended period of time, with trees back- and frequency. Researchers found that waterlogging hoed for examination of root systems, • Do not initiate irrigation until pres- symptoms started appearing in May. and the impact of long-term flooding sure chamber measurements show Walnut trees had healthy crowns and from continued seepage on walnut root trees are 2-3 bars below the fully roots in the top foot of soil, even though health and tree water status. watered baseline (more dry) and they were leafing out late, or had leafed only irrigate enough to bring the out and died back. Orchard Management Conditions trees back up to about 0.5 to 1 bar below the baseline by applying short “These symptoms were caused by The research team provides the fol- sets of irrigation. waterlogging of deeper roots where soils lowing information to growers: • It is not a good idea to prune or were still saturated. In previous years, fertilize trees after flooding. Pruning flooded trees usually had dead crown • Flooded orchards will likely respond will reduce both carbohydrate re- tissue and rot of shallow roots from wa- to irrigation differently than normal, serves and leaf area, while fertilizer terlogging and/or Phytophthora,” Hasey since root systems are compromised. applications may mostly go to waste reported. • In saturated soils, fine roots die, and and delay or damage root produc- depending on the extent of flooding, tion. The best approach would be In river bottoms where walnut trees larger roots can die as well. It takes to wait, and let the tree adjust to were partially submerged for prolonged time for the root system to regain the altered environmental condi- periods, the research team first noticed functionality and re-start new fine tions while managing irrigation as and isolated Phytophthora species from root production after flooding. described above to avoid further bleeding root and aerial trunk cankers • If the water table level below the soil damage to the root system. first around mid-May. surface drops gradually, trees may be able to continue to produce func- Where to Find Help Another observation of the team tional roots at increasingly deeper concerned a young Chandler orchard levels over time. Initial irrigation Hasey and her team said there are sev- on RX1 rootstock, of which a third of could be delayed for some time, as eral potential resources and programs the orchard had seepage from January to deeper roots may maintain water for growers who suffered flood-related early May. In this orchard, whereby only uptake. damages. Resources include: Farm Ser- the tops of the berms were not sub- • However, if the soil remains saturat- vice Agency; Tree Assistance Program; merged, flooded trees leafed out about ed at some level below the surface, Emergency Loan Assistance; Emergency a month later than those not flooded. the only functional roots may be at Conservation Program; County Asses- Some trees were struggling while others a very shallow depth and irrigation sor; and Tree loss calculators based on are continuing to leaf out and grow. may have to be initiated earlier than UCCE cost studies through Agricultural normal. In this case, shorter but & Resource Economics at UC Davis. Two Potential Areas of Concern more frequent irrigations could help avoid further damage to roots in the For more complete summaries of the In their study the research team has upper zone. resources available and how to report found two potential problems of con- • Carefully monitor both soil water tree damage visit: cern: Diseases caused by Phytophthora; levels and tree water status so that http://www.sacvalleyorchards.com/blog/ and impact of waterlogging on the root the trees can be gradually brought almonds-blog/resources-for-flooded-or- system. back to health. Soil based monitor- chards/ ing, using Watermark® soil moisture “We know the ‘water mold’ Phytoph- sensors installed at different depths, Comments about this article? thora is found in surface water and will let you know the level where We want to hear from you. Feel free to email us at [email protected] 38 West Coast Nut July 2017 www.wcngg.com 41 SGMA's

Will Change the Way We Farm

By Roger A. Isom President/CEO Western Agricultural Processors Association

n 2014, the California Legislature passed,I and the Governor signed, a three lature felt compelled to pass a law that The act requires the formation of bill package that will most likely become ultimately will regulate the pumping of local groundwater sustainability agen- the most impactful regulation to Califor- groundwater. Known as the Sustainable cies (GSAs) that will assess groundwater nia in a long, long time. Driven by the Groundwater Management Act (SGMA), conditions in their areas and create plans huge drawdown in groundwater due to it will not only impact agriculture, to manage groundwater sustainability. the multi-year drought, pumping restric- but cities and anyone else who pumps So what does this mean? Once GSAs are tions in the Delta, and counties starting groundwater. formed, they will have several manage- to ban further well drilling, the Legis- ment tools to help bring the basin to a

40 West Coast Nut July 2017 sustainable level. The GSAs can require Board (SWRCB) on any inadequacies. and how limiting will they be. registration of groundwater wells, man- After this consultation, the SWRCB will date extraction reports from wells, and notify the GSA that they will be desig- even impose limits on wells. And yes, nated “probationary” unless they can they will have the ability to assess fees to address the deficiencies within 180 days support the development and manage- of notification. If they fail to address the ment efforts. deficiencies, the SWRCB can create their own interim plan and assume authority Once formed, the GSAs will have 20 over the GSA until the GSA can create years to develop and implement ground- an approvable plan. water management plans to achieve “sustainability”. These plans are called So what does “sustainable ground- Groundwater Sustainability Plans or water management” mean? Well, the GSPs. GSPs are due by January 31, 2020 legislation calls for managing a ground- for critically over-drafted basins, and water basin in such a manner as that it January 31, 2022 for high and medium does not cause “undesirable results.” The priority groundwater basins not in a legislation defines “undesirable results” condition of critical overdraft. Much as the following: of the San Joaquin Valley is listed as “critically over-drafted”. Once submitted, • Chronic lowering of groundwater the California Department of Water Re- levels sources (DWR) will review the GSPs for •Significant and unreasonable reduc- compliance. Compliance is determined tions in groundwater storage on whether or not DWR believes the •Significant and unreasonable seawater GSA can achieve sustainability within 20 intrusion years. If DWR determines that the GSA •Significant and unreasonable degrada- most likely will not achieve sustainabil- tion of water quality ity or is inadequate, DWR will consult •Significant and unreasonable land with the State Water Resources Control subsidence •Surface water depletions that have significant and unreasonable adverse impacts on beneficial uses

While DWR does not say this will take away the ability of water users to pump groundwater, it is pretty obvious what has occurred over the past several years will not be allowed to continue under SGMA. It does not affect water rights, but it can be reason- ably assumed that restrictions will follow, especially in critically

Cont.on Page 42

www.wcngg.com 41 Continued from Page 41 over-drafted basins.

Once the GSA has been formed, the real work begins. The development of the GSP is where the details are and where growers need to be involved. If you are not involved in your GSA, you need to be. The legislation allowed for, and the Governor and the DWR staff have maintained, that “groundwater management is best accomplished locally.” The SWRCB will only step in if the GSP is insufficient. This is where the questions begin. How will the local GSA accomplish “sustainability?” What practices will be put in place for growers to follow? Will cropping patterns change? The answers to these questions set the stage for what is to come, and it is not pretty. It is not a matter if restrictions will be employed, it is a question of when

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42 West Coast Nut July 2017

Figure 1. English walnut (Juglans regia) infested with WTB and severely affected by TCD. Symptoms of branch dieback, bleeding at emergence/entry holes.

Photo credit: M. Yaghmour later in 1997 and 2001 that black walnut mortality in Utah, Oregon, and New Mexico, and somewhat later in Colo- rado, was associated with walnut twig beetle (WTB) Pityophthorus juglandis. However, it was not until 2008 that tree mortality was attributed to WTB feeding in the phloem, and to canker formation around the WTB galleries caused by a new fungus. The fungus was later 1,000 described as Geosmithia morbida and the disease was called Thousand Cankers Disease (TCD). The name was proposed Cankers due to the many cankers developed around beetles’ galleries that coalesce and girdle twigs and branches resulting Disease: in decline and mortality. Currently, TCD is considered a com- Everything plex and emerging disease in the US and California, and it is responsible for decline, dieback, and death of eastern black You Need to walnut in western US, and is currently spreading in the native range of the eastern black walnut. It is also widespread in Know For Walnuts California causing decline in California black walnuts and disease in English walnut orchards. Beside its spread in the By Mohammad Yaghmour and Elizabeth Fichtner US, it was reported in Italy on eastern black walnut and English walnut trees he walnut tree (Juglans sp.) is well tance in the ecological system as a source and vectored by the WTB. Tknown for its valuable wood and for food and shelter for wildlife, J. hindsii timber quality and its nutritious nut. has an economic value for its wood, and Any plant fungal disease is a function Different native species of walnut are an as a rootstock for English walnuts (J. of three major factors, the pathogen, important part of the ecological system regia) in commercial orchards or as a a susceptible host, and environmental in North America. Eastern black walnut parent in the hybrid rootstock ‘Paradox’ conditions conducive to disease de- (Juglans nigra) is native to eastern North (J. hindsii × J. regia). velopment. In this case, the pathogen America from the northeast in Vermont is being vectored by an insect making and southern Ontario to Minnesota California is also considered the the insect an important part of disease and south to Florida. It also ranges east number one state for producing English development. Thus, an understanding from the Atlantic coast to central Texas walnuts with approximately 99 percent of the biology of the insect, the fungus, except the Mississippi River Valley and of the total U.S. production. English host susceptibility and their interaction Delta. Juglans nigra has an important walnut, which is native to Asia and was is necessary to understand the disease economic value estimated at more than first introduced to California later in the biology and development, and thus help $500 billion for its wood and timber eighteenth century with the first com- in developing effective control methods. alone. Among the other species that are mercial orchard planted in 1843. Walnut In this article, we will introduce the signs considered native to the US with natural is a high value crop and considered one and symptoms of this disease as well the range are Arizona walnut (Juglans ma- of the major nut crops grown in Califor- different factors contributing to its devel- jor), Texas walnut (Juglans microcarpa), nia and ranks in the top ten commodi- opment, and how the current advances and California black walnuts (Juglans ties in California with approximately 300 may help control this disease. californica and Juglans hindsii). thousand acres and a market a value of approximately $977 million in 2015. Signs and Symptoms In California, there are two native ranges of California back walnut species; In early 1990’s, black walnut decline Affected walnut trees will show symp- Southern California black walnut (J. cal- and mortality was observed in Utah and tom of branch die back and flagging ifornica) and Northern California black Oregon and was not associated to any (Figure 1). Once we see those symp- walnut (J. hindsii). Beside their impor- biotic cause at the time. It was not until toms, it is always advised to examine the

44 West Coast Nut July 2017 tree and take a closer look at the bark surface of twigs and the main trunk for signs of entry/exist holes created by the beetle. These will be tiny holes with a size less than 0.04 inch in diameter (Figure 2). The beetle prefers to attack branches that are greater than ½ - ¾ of an inch in diameter. In many cases, affected trees exhibit bleeding around beetle holes, and removal of the surface bark will show cankers development around beetle galleries in the phloem tissue, with sometimes presence of the beetles in the galleries, or signs of fungal mycelium and spores that could be visible in the galleries (Figure 3). As Figure 2 (top left): Entry the cankers increase in size, they may and exit holes created by the coalesce girdling branches and causing walnut twig beetle (Pityophtho- tree decline and mortality under severe rus juglandis) on English walnut. infections and beetle colonization. Photo credit: Elizabeth Fichtner

The Beetle Figure 3 (left): Signs and symptoms of thousand cankers The WTB is very small and it’s ap- disease. (A) Peeling the bark proximately 0.06 inch in length (Figure from a Paradox branch reveals 4). The beetles and the larvae overwin- canker development around ter in the host tissue and emerge be- beetles’ galleries. (B) Beetle tween January and March in California. boring into the phloem of an Once they emerge, male WTB looks for English walnut tree. a susceptible host and starts to colonize the tree first by initiating new galleries in Figure 4 (above): Walnut the twigs or the main trunk. During this twig beetle (Pityophthorus process, they produce an aggregate pher- juglandis). Approximately 0.06 omone to attract two to three females for inches long mating. The females lay the eggs in gal- Photo credit: L. L. Strand. leries in the phloem and xylem surfaces, (Source: http://ipm.ucanr.edu/ and once the eggs hatch, the larvae start EXOTIC/thousandcankers.html) to feed and create feeding tunnels along the wood grain. After that, the larvae pupate and emerge as adults and move to colonize the same tree or move to a different tree.

Entomologists at UC Davis and the omone and possible US Forest Service identified the aggre- future use to enhance gate pheromone which was a tremen- IPM programs to dous help in studying the beetle’s biology control this pest such and behavior. They found that the beetle as the use of mating generally has two flights during the sea- disruptions techniques. son after their initial emergence between Excellent detailed January and March. The primary flight information about is between May and July; and a second- monitoring guidelines ary flight from September to October. for the WTB as well de- The importance of these studies is that tecting and identifying now we have a better idea about WTB the beetle can be found seasonal flights and biology allowing us to monitor the WTB using the pher- Continued on Page 46

www.wcngg.com 45 Continued from Page 45 During 2012 and 2013, extensive sur- walnut. Keeping TCD from spread- veys took place in major English walnut ing can be achieved by preventing the in this UCIPM publication. producing counties in California to look movement of unprocessed wood as well http://entomology.ucdavis.edu/ at the incidence of the disease. What we as firewood. In California English walnut files/194027.pdf found is that TCD is more prevalent in orchards, growers are advised to monitor the southern San Joaquin valley (Tulare closely newly and mildly infected trees Host Susceptibility and Kings Counties) than in the Sacra- and remove and burn or chip trees when mento Valley area (Yuba, Sutter, Solano, they are severely infected and showing The most susceptible host to TCD Yolo Counties). Additionally, other field sever decline. is eastern black walnut. In field inocu- observations suggest that trees infected lation and greenhouse studies, Juglans with Agrobacterium tumefacians, the It is always important to remember spp. showed variable susceptibility to cause of crown gall, may be more suscep- that TCD is a complex disease, and TCD. In California field inoculation tible to WTB attack, making them more beetle feeding and reproducing behavior studies comparing susceptibility of seven likely to develop TCD in addition to by itself does little to tree health. It is the Juglans spp, English walnut and north- crown gall. Further research is needed to fungus that hitch-hikes on the beetle that ern California black walnut developed fully characterize the potential relation- is causing the damage. The tremendous intermediate cankers compared to other ship between the two diseases. advancements accomplished in un- species tested in this experiment. Also, derstanding beetle and fungus biology, Chinese wingnut (Pterocarya stenoptra), Control their interaction with the host, as well as a member of the Juglandaceae family, current ongoing research to understand was found to be a host to WTB and Currently, use of pesticides as a con- volatile organic compounds that repel or susceptible to TCD in California. In the trol method is not available for manage- attract the beetle, and selecting walnut past, Chinese wingnut was evaluated in ment of this disease. However, exclusion rootstocks resistant to plant diseases, in- breeding programs as a potential parent as a management practice is an import- cluding TCD, will all help combat TCD for hybrid rootstocks for English walnut ant strategy, and this can be achieved in English walnut orchards. More infor- in California. Hence, this work provides using quarantine. Many states estab- mation about the disease and the beetle valuable information for future rootstock lished quarantine areas to prevent TCD can be found under UC IPM Exotic and breeding programs. spread into new areas where TCD was Invasive Pests page http://ipm.ucanr.edu/ not reported, previously, on eastern black EXOTIC/index.html.

46 West Coast Nut July 2017

Nutrient Management of Zinc in Pistachios

By Sabrina Hill, Contributing Writer

inc is among the most likely defi- Zcient micronutrients for pistachios in the California growing areas, but there are ways for growers to monitor, prevent, and treat low zinc levels in the orchard. As summer progresses, growers should be considering leaf sampling to check for zinc deficiency in the orchard. soils that limit root growth can also be not soluble, they remain in solid forms Author’s note: Information herein problematic. Methyl Bromide fumiga- that the plants cannot absorb properly. was collected from scholarly papers and tion causes a temporary loss of mycor- presentations by University of Califor- rhizal fungi and ultimately less zinc. Look for symptoms of zinc defi- nia (UC) advisors Bob Beede, Brent Lime reduces zinc availability as well, ciency in spring. The seasonal onset of Holtz, and Craig Kallsen. as do high magnesium or phosphorous symptoms of zinc deficiency is mid to levels. late season, especially in young bearing Importance of Zinc trees. Younger leaves show zinc defi- With the Environmental Protection ciency while older growth does not, due Zinc is necessary for formulation of Agency (EPA) phaseout of Methyl to the limited mobility of zinc in the Auxin, which plays a role in cell elonga- Bromide more than ten years ago, there plant. Over the course of the season, tion and the forming of chloroplast. It is is less issue with the temporary loss of growers can look for delayed bud needed for the development of pollen, mycorrhizal fungi. Arbuscular my- opening, terminal leaves that are small along with flower bud differentiation corrhizal fungi are microscopic fungi and yellow, wavy leaf margins, terminal and fruit set. naturally occurring in soil that form dieback, reduced nuts and more blanks. a symbiosis with plant roots. Studies Factors and Signs of show that this process helps plants Testing for Zinc Levels Zinc Deficiency absorb zinc through the roots. Growers can use soil sampling and There are several factors relating to Alkaline soils are more susceptible to leaf sampling to get an accurate picture zinc deficiency in pistachios and other zinc deficiency. Alkaline soils have pH of the zinc needs and uptake in their nut crops. First, cut areas are more values of 7.0 or greater and can lead to crop. likely to be deficient. In addition, zinc deficiencies in other nutrients as well. has restricted solubility and movement The solubility of several nutrients low- A single orchard can have several in soils, which is made worse in alkaline ers as the pH level increases, including different soil types within it, due to soils and limitation in water flow. Root iron, phosphorus, copper, boron, and conditions such as sand deposits, cuts health is important for zinc uptake, so manganese. When these nutrients are or fills, or a number of other factors. In

48 West Coast Nut July 2017 addition, soils often change with depth. Unlike leaf sampling, soil sampling typically does not need to be performed every year.

Other UC guidelines for soil sampling are:

• Take three to ten sub samples for each area. Then combine them by depth into single s amples

• Repeat the samples through out the orchard

• Though pistachios are deep rooted, the suggested protocol is to sample at one foot incre- ments down to three feet

Leaf sampling is a widely prescribed testing procedure for zinc and other nutrients in nut crops. It shows how successfully the tree is pulling nutrients from the soil and transporting those nutrients throughout the plant. Leaf sampling should be performed every year. Zinc levels for mature trees in late Photos courtesy of Sabrina Hill Continued on Page 50

www.wcngg.com 49 Continued from Page 49 • Deliver the sample to the lab be needed. within 24 hours July and August are suggested by UC Acidifying soils with sulfuric or advisors to be 10 to 15 PPM (parts per • Optimal leaf tissue concentra- phosphoric acids will correct some million). tion: 10-15 ppm nutrient deficiency in alkaline soils. It is also possible and in some cases benefi- The UC guidelines for effective leaf • Critical value seven ppm cial, to treat soil with sulfur dust where sampling are: there is lime. Treating for Zinc Deficiency • Collect the sample from late Other recommendations from UC July through mid-August Once a grower has identified zinc farm advisors include: deficiency in the orchard, there are sev- • Sample non-fruiting branches, eral possible courses to take and con- • Zinc sulfate in late posthar- six ft. (1.8 m) from the ground siderations to keep in mind. Treatments vest or bud-swell. can include applying fertilizers, differ- • Choose fully expanded ent irrigation management techniques, • Single post-bloom foliar spray sub-terminal leaflets and changing the pH of the soil. of zinc sulfate and copper ap plied when canopy is 50-90 • Collect four-10 leaflets per tree Zinc cannot be ‘stored’ by the plant, percent fully. therefore over-applying zinc for later • Sample 10-20 trees/orchard use by the plant is not effective and • Fertigating with non-chelated block ultimately can be a waste of money. zinc and copper in alkaline Foliar fertilizers benefit only the tissues soils is NOT effective. • Do not include leaflets that sprayed and do not help plant growth have received in-season nutri- that is developed after application. Fer- • Fall application in late ents sprays tilizers have limited long term effective- October (50 percent defolia- ness, therefore, repeat applications may tion) requires high

50 West Coast Nut July 2017 rates of Zinc Sulfate 36 percent powder at 40 pounds/100 gal. water. Liquid Zinc Sulfate 12 percent also effective at 10 gal./100 gal. water.

• Delayed dormant timing (early March) also effective at above rates.

• Much lower rates required at 50 percent leaf expansion (late April) before leaves complete wax development. Two pounds Zinc Sulfate 36 percent per acre. Buffer with citric acid to pH=5.0.

• In season sprays correct deficiency on new growth, NOT old.

• Repeated treatments may be required.

• Supply required throughout all stages of growth and reproduction

Zinc is a vital nutrient for pistachios. Deficiencies in this micronutrient and others can lead to low levels of pollen and poor fruit set, which ultimately result in a smaller yield and loss of potential profits for the grower. Local farm advisors are available to assist in creating sampling programs and to answer questions. Growers are encouraged to contact UC farm advisors with any concerns and/or inquiries.

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www.wcngg.com 51

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58 West Coast Nut July 2017