Progressive Crop Consultant - January - February 2017

Progressive

Crop Consultant The Leading Magazine For Ag Professionals

January - February 2017 Thermal Infrared Sensors for Postharvest Deficit Irrigation of Peach Using Nutrient Symptoms to Diagnose Plant Nutritional Management Winter Sanitation in Nut Crops

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Volume 2 : Issue 1

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UCCE Butte/Glenn Counties Almond & Walnut Day 3 PCA Credits (0.5 Laws, 2.5 Other) and CCA credits will be requested.

JANUARY 19, 2017 7:30am - 1:30pm

Main Session

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2357 Fair St., Chico, CA 95928

7:30am

Registration/Trade Show (CE Credits: 15 minutes; Other)

8:00am

Laws and Regulations Update: TBD, Butte County Agricultural Commissioners Office

8:30am

Spider Mite Control in Almond & Walnut Orchards: Dr. Jhalendra Rijal, UCCE IPM Advisor, Stanislaus County

9:00am

Symptoms of Nutrient Deficiencies (and How to Correct Them): Richard Buchner, UCCE Orchards Advisor, Tehama County

9:30am

Break/Trade Show

10:00am

California Walnut Board Update: TBD, California Walnut Board

10:15am

Almond Board of California Update: TBD, Almond Board of California

10:30am

Phytophthora, Crown Rots & Root Rots: Dr. Dani Lightle, UCCE Orchards Advisor, Glenn, Butte & Tehama Counties

11:00am

Almond Disease Control: Dr. Jim Adaskaveg, Dept. of Plant Pathology, UC Riverside

11:30am

Butte-Yuba-Sutter Water Quality Coalition Updates: Kayla Zilch, Program Coordinator, Butte County Farm Bureau

12:00pm

Free Industry Tri-Tip Lunch

1:00pm

Trade Show (CE Credits: 15 minutes; Other)

1:30pm

Adjourn

Hands-on Breakout Sessions

Breakout sessions are limited to 25 people each. Session registration will be available beginning at 7:30am.

8:30, 10:30, 11:30am

Navel Orangeworm Control Using Mating Disruption: Dr. Emily Symmes, UCCE IPM Advisor, Sacramento Valley.

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9:00, 10:00, 11:00am

Using Dendrometers for Irrigation Management Decisions: Allan Fulton, UCCE Water & Irrigation Resources Advisor, Tehama County.

Allan will have a tree dendrometer on hand and demonstrate how this new technology is used and share data supporting its utility.

9:00, 10:00, 11:00am

Understanding and Optimizing your Spray Coverage: Dr. Franz Niederholzer, UCCE Orchards Advisor, Colusa County.

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In This Issue Thermal Infrared Sensors for

6 Postharvest Deficit Irrigation of Peach

Contributing Writers & Industry Support

Ben Faber, PhD UCCE Crop Advisor, Ventura/Santa Barbara County

Using Nutrient Symptoms to Diagnose

10 Plant Nutritional Management

Sabrina Hill Contributing Writer Cecilia Parsons Contributing Writer

16 Winter Sanitation in Nut Crops

Emily J. Symmes, PhD IPM Advisor, Sacramento Valley Dong Wang USDA-ARS Water Management Research Unit

18

IPM Technology

Looking Back to Look Forward

22 UC Weather Information UC Cooperative Extension Advisory Board Kevin Day

County Director and Pomology Advisor, Tulare/ Kings County

David Doll

UCCE Farm Advisor, Merced County

Dr. Brent Holtz

Steven Koike

Plant Pathology Farm Advisor

Emily J. Symmes

IPM Advisor, Sacramento Valley

Kris Tollerup

IPM Advisor, Fresno/ County Director and Madera Counties, UC Pomology Farm Advisor, Statewide IPM Program San Joaquin County and Cooperative Extension, Kearney Ag Research and Extension Center 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.

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Photo Credit: Dong Wang

PEACHES

Thermal Infrared Sensors for Postharvest Deficit Irrigation of Peach Dong Wang USDA-ARS Water Management Research Unit

C

alifornia has been in a historic drought and the lack of water has been a major problem for agriculture especially for crops that depend on irrigation. Deficit irrigation may be used in some cropping systems as a potential water saving strategy (Goldhamer et al., 1999). The term “Deficit Irrigation” simply means irrigating at less than the full amount required by crop evapotranspiration needs. For fruiting trees such as peaches, because fruit yield and quality at harvest may not be sensitive to water stress at some developmental stages such as during the

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non-fruit bearing postharvest season, there is an interest in applying deficit irrigation strategies. Deficit irrigation has not been widely used due partially to the lack of effective and fast methods of monitoring plant water stress in near real-time and determining associated risks of applying deficit irrigation.

When crops are managed under deficit irrigation, the margin of error in timing and amount of water application becomes smaller before causing yield losses. Monitoring the soil and plant water status is more critical for reducing risks of a crop failure or permanent damage to the trees. However, current established techniques of monitoring the soil and plant water status such as neutron probe readings of soil water profile and

January/February 2017

pressure chamber measurements of stem water potential are labor intensive, and lack the timeliness needed for irrigation scheduling purposes.

Thermal Infrared Sensors Thermal infrared sensors have been used by researchers to measure crop canopy temperature and relating the temperature measurement to water stress. For example, infrared canopy temperature was used by Jackson et al. (1981) to estimate water stress in annual crops such as wheat. The canopy temperature method was also applied to irrigation scheduling for cotton production (Wanjura and Upchurch, 1997). Using canopy temperature measurement, the canopy to air tem-

Canopy-air temperature difference (˚C)

Figure 1. Correlation between stem water potential and infrared canopy – air temperature difference.

Photo Credit: Dong Wang

Irrigation Treatment and Sensor Deployment In a multi-year field study, an early-maturing peach was irrigated using furrow, drip, and micro-sprinkler systems under both full and deficit irrigation schemes. The trees were early-ripening “Crimson Lady” (Prunus persica (L.) Batsch) peach on “Nemaguard” rootstock. During the growing season, stem water potential was measured weekly or bi-weekly from both the full and deficit irrigation blocks. Infrared temperature sensors were installed in the orchard in both the full and deficit blocks irrigated by furrow, drip, or micro-sprinkler methods. These temperature sensors were mounted on galvanized metal pipes extending above the tree canopy. The center of field of view for each sensor was aimed at the middle three trees of the center row for each measurement block. A datalogger system was used to record temperature readings at 15 minute internals and readings were averaged to hourly outputs for each growing season. Thermocouples were installed in the orchard to record air temperature at the same frequency as the infrared sensors, and hourly canopy-air temperature difference was computed. A linear regression was made between the canopy-air temperature difference and stem water potential measurements. Correlation between stem water potential and canopy-air temperature difference showed a significant relationship (R2 = 0.6) where more negative potential values corresponded to larger canopy-air temperature differences (Figure 1). This is expected because when plants are under water stress, stomatal resistance

Stem water potential (MPa)

perature difference was correlated to the vapor pressure deficit in peach trees and used to reference stomatal responses to water stress (Glenn et al., 1989).

Approximately 10,000 ha of commercially-grown peach trees in central California depend on irrigation as the primary source of water in the peak summer growing season. A potential solution for managing water shortage is to use deficit irrigation during postharvest growth stages and to use thermal infrared sensors to monitor water stress in near real-time.

Continued on Page 8 January/February 2017

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Treatment

2008

2009

2010

2011

2012

2013

2014

2015

Continued from Page 7

Furrow, full

22a

12

17ab

26a

19a

20a

14a

15a

Furrow, deficit

22a

11

19a

22b

15b

18ab

10ab

13ab

Drip, full

21a

11

16b

24ab

16b

18ab

10ab

13ab

Drip, deficit

18b

10

18ab

22b

17ab

16b

8b

10c

Micro-sprinkler, full

na**

na

na

na

16b

15bc

13a

12bc

Micro-sprinkler, deficit

na

na

na

na

16b

14c

12ab

11bc

increases thus stem water potential is more negative. At the same time, transpiration decreases thus the canopy could be at higher temperature than the ambient air due to reduced evaporative cooling. The graph also indicates that infrared temperature measurement is not sensitive to stem water potential variations in the range of -0.5 to -1.0 MPa. This may imply that the infrared canopy temperature approach is applicable to water stressed conditions such as under deficit irrigation, but not sensitive to well-watered situations. The regression equation was subsequently used to guide irrigation scheduling (Zhang and Wang, 2013).

Table 1: Fruit yield (kg/tree) under different irrigation regimes*

Fruit size (kg/fruit)

Fruit yield (kg/tree)

*Different letters indicate significance at P < 0.05 using the Tukey’s studentized range (HSD) test. ** na = data not available.

Total postharvest irrigation during the previous season June-November (mm)

Photo Credit: Dong Wang

Figure 2. Fruit yield and size over previous season postharvest irrigation totals.

Data from both full and deficit treatment of furrow, drip, and micro-sprinkler irrigation blocks from 2013-2015.

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January/February 2017

Peach Yield and Size Peach fruit was harvested each year by a commercial contract crew following typical farming procedures. Only marketable fruits were harvested and a total of two to three picks were used during each season. The total fruit weight per tree and number of peaches per tree were measured for each treatment block. Average weight per fruit or fruit size was obtained by dividing the weight per tree with number peaches per tree. Fruit yield (weight per tree) under different irrigation treatments is shown for each year for the multi-year field study (Table 1). For furrow irrigation there is no significant difference in yield between full and deficit irrigation except in 2011 and 2012. For drip, the difference is significant in 2008 and 2015. For micro-sprinkler blocks, no significant difference was found in fruit yield.

Average fruit yield and size of fruit from 2013 to 2015 over furrow, drip, and micro-sprinkler methods showed no significant change when cumulative irrigation increased from an average of 360 mm to 1360 mm during the postharvest season of 2012-2014 (Figure 2).

The average fruit yield was 11.9, 12.9, and 14.3 kg/tree when previous year postharvest irrigation totals was 360, 823, and 1360 mm, respectively. The large variation in yield from year to year was attributed, at least partially, to orchard management practices such as annual pruning and fruit thinning (see also Table 1). The size of fruit remained nearly constant at approximately 0.14

kg/fruit.

The multi-year study has demonstrated that deficit irrigation and infrared thermal sensing are potential management strategies for reducing overall crop water use and monitoring tree water stress. Peach tree water status can be estimated from thermal infrared temperature sensors in real-time, and the remotely sensed temperature data correlated to stem water potential measurements using the pressure chamber method. Future work includes determination of optimum amount of water deficit that can be used without causing unacceptable yield losses.

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References Glenn, D.M., Worthington, J.W., Welker, W.V., and McFarland, M.J. 1989. Estimation of peach tree water use using infrared thermometry.

J. Am. Soc. Hort. Sci. 114:737-741.

Goldhamer, D.A., Fereres, E., Mata, M., Girona, J., and Cohen, M. 1999.

Sensitivity of continuous and discrete plant and soil water status monitoring in peach trees subjected to deficit irrigation. J. Am. Soc. Hort. Sci. 124:437-444.

Jackson, R.D., Idso, S.B., Reginato, R.J., and Pinter, Jr., P.J. 1981. Canopy temperature as a crop water stress indicator. Water Resour. Res. 17:1133-1138.

Wanjura, D.F., and Upchurch, D.R. 1997. Accounting for humidity in canopy-temperature-controlled irrigation scheduling. Agric. Water Manage. 34:217-231.

Zhang, H., and Wang, D. 2013.

Management of postharvest deficit irrigation of peach trees using infrared canopy temperature.

Vadose Zone J. 12(3): doi:10.2136/ vzj2012.0093.

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NUTRIENT MANAGEMENT

Photo Credit: UC Statewide IPM Program

Using Nutrient Symptoms to Diagnose Plant Nutritional Management ON TERMINAL BUDS: - Ca & B ON YOUNG LEAVES: - Cu, B, Fe & Mn ON OLD LEAVES: - N, P, K, Mg, Zn, & Mo

Ben Faber UCCE Crop Advisor, Ventura/Santa Barbara County

S

Positions on a plant where deficiencies occur.

Boron toxicity citrus (tip burn, older leaves).

Sodium toxicity avocado (marginal leaf burn, older leaves).

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Progressive Crop Consultant

ince Greek and Roman times, the appearance of a plant has been used to help identify plant health.

The plant speaks through distress signals. The message may be that there is simply too little or too much water. Or the sign may tell us of a disease caused by a microorganism, such as a bacteria, virus or fungus.

The plant may show symptoms of attack by nematodes, insects or rodents or from injuries from frost or lightning. According to the plant species these signals may differ slightly, but frequently they can be generalized.

It is also possible to generalize about the signals linked to the nutritional status of a plant. Learning these symptoms can alert us to appropriate steps to correct the toxicity, deficiency or imbalance of nutrients.

There are 17 elements essential for plant growth. Hydrogen, oxygen, and carbon come either from the air or water. The others come from the soil. Depending on the quantity needed by the plant, these are called either primary or trace (micronutrients) nutrients. The micronutrient nickel is required in such small amounts (50-100 parts per billion) by plants that it was identified only in 1990 as being an essential nutrient. Other micronutrients are iron, manganese, boron, chlorine, zinc, copper and molybdenum. Some other nutrients have been identified as being essential for only certain plants, such as silicon for sugar cane.

The primary nutrients are measured on a percent (parts per 100) dry weight tissue basis. These are nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. The

January/February 2017

trace elements are measured on a part per million dry weight basis.

For example, a typical analysis of a dried leaf from a healthy cherimoya might show two percent nitrogen, one percent potassium, 100 ppm (parts per million) iron and 50 ppm boron.

Although plants require more primary than trace nutrients, all the essential elements need to be present for a healthy plant. An excess, deficiency or even an imbalance of these elements will lead to individual symptoms which are characteristic to most plants.

Furthermore, these symptoms take on characteristic positions.

The micronutrients typically show up on young, expanding tissue (calcium is a macronutrient that also shows up on young tissue), while macronutrients and toxicities generally show up on older tissue.

Because of our climate and soils, some nutritional issues are more common in some areas than others.

Acid soils in high rainfall areas will typically show calcium, magnesium, and boron deficiencies than those in high pH soils with low rainfall.

Iron, manganese, copper and zinc are more common in higher pH soils than in low. Nitrogen, phosphorus and potassium can appear on plants in many different environments.

Excess or toxicity (usually related to irrigation practices) Boron—chlorosis (yellowing), leading to tissue death (necrosis) along the margins of older leaves.

Sodium, Chloride—necrosis of the leaf tips and margins on older leaves. They often occur in combination.

Deficiency Phosphorus—frequently the only Continued on Page 12

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Page 00

Photo Credit: UC Statewide IPM Program

Continued from Page 10

Chloride toxicity avocado (tip burn, older leaves)

Phosphorus deficiency in pear (small leaves, shortened internodes, older leaves).

Potassium deficiency in citrus (leaf curling, but often marginal leaf burn on older leaves).

symptom is smaller plants, but occasionally the leaves are darker than normal or may have a reddish cast, a common symptom in sweet corn.

Phosphorus deficiency in California trees is rare.

Potassium—scorching or firing along leaf margins that usually first appears in older leaves. Plants grow slowly and have a poorly developed root system. Stalks are often weak and fall over.

Nitrogen—plants are light green or yellow. Older leaves are often affected first, but in trees the chlorosis may appear on any part of the plant.

Zinc—depending on the plant there may be interveinal (between the leaf veins) chlorosis on younger leaves, but frequently the leaves are small and appear in a rosette.

Iron—very sharply defined interveinal chlorosis of younger leaves, with little size reduction. Can often Continued on Page 14

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January/February 2017

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Page 13

Continued from Page 12 be associated with wet soil conditions.

Manganese—mild interveinal chlorosis of younger leaves, with no size reduction.

In Acid Soils especially, Deficiencies in: Boron—leaves can have general yellowing often with holes.

Calcium—leaf margins light colored, entire leaf blade made be thickened.

Magnesium—a pointed shape appears in the center of the leaf.

Photo Credit: UC Statewide IPM Program

Nitrogen deficiency in avocado (general yellowing of older leaves).

Zinc deficiency in citrus (smaller leaves on young tissue, older unaffected leaves in background).

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Progressive Crop Consultant

Iron deficiency on citrus (fine interveinal yellowing, young leaves).

January/February 2017

These and other problems can be corrected with appropriate fertilizers, amendments and manures and also by soil and water management.

In well-managed plants you may never see these signs, but learning the signals can help direct your activities if you do.

All plant species show similar responses to low or high levels of nutrients. Some show the symp-

Photo Credit: UC Statewide IPM Program

Further Reading Chapman, H. 1966. Diagnostic Criteria for Plants and Soils University of California Press (the bible if you can find it).

Foth, H.D., 1999. Fundamentals of Soil Science. John Wiley and Sons, Inc. Havlin, J.L., J.D. Beaton, S.L. Teasdale and W.L. Nelson. 2005. Soil fertility and nutrient management: An introduction to nutrient management. 7th Ed. Pearson/Prentice Hall.

Manganese deficiency on citrus (blotchy yellow interveinal areas).

Singer, M. J, and D.N. Munns. 2005.

Soils: An Introduction. 6th Ed. Pearson/Prentice Hall.

Photo Credit: Tony Wiley

toms more clearly than other plants.

Sweet corn is a wonderful indicator plant which develops very prominent symptoms according to the deficiency. Planting a row of sweet corn (not field) is a tasty way to determine if your soil has a generic nutritional problem.

The other thing to remember is that soils are important, but in irrigation situations, water management is an overriding factor. How, when and how much applied can often mask an irrigation problem.

Once irrigation is managed correctly, then start looking at nutritional problems. A tree has lots of reserves stored in different parts of its structures, and it will often call on them first before taking up nutrients from the soil. Soil analysis works well for an annual plant, but for tree it is more important for diagnosing pH problems and toxicities, such as boron, sodium and chloride.

Soils in most cases are made of iron, silicon, aluminum and oxygen.

But often in calcareous soils, iron can be deficient. It is there, but just not available. Correcting soil pH is the most effective long range effect.

Many trees have mycorrhizal symbioses that help take nutrients like phosphorus and zinc.

A classic example of a fruit tree that is tremendously efficient at recycling nutrients from its fallen leaves is the avocado. Often by the time the tree is 8-10 years of age, the amount of nutrients, such as nitrogen and potassium, can be reduced compared to the wildly growing young tree. In this case, annual tissue analysis can be extremely important in adjusting the yearly fertilizer applications along with the crop load, and also learning to read the tree’s language.

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University of California, ANR. 2015.

California Master Gardener Handbook, 2nd Ed. UC ANR Publication 3382 Western Plant Health Association.

2010. Western Fertilizer Handbook.

Waveland Press.

Boron deficiency in avocado (young leaves with holes)

Websites Curtis, N.C. http://nzic.org.nz/ ChemProcesses/soils/2A.pdf New South Wales Dept. of Primary Industries. Plant Nutrients in the Soil. http://www.dpi.nsw.gov.au/agriculture/resources/soils/improvement/plant-nutrients University of Arizona. Guide to Symptoms of Plant Nutrient Deficiencies. http://extension.arizona. edu/sites/extension.arizona.edu/ files/pubs/az1106.pdf

Calcium deficiency in citrus fruit with stylar end rot, leaves often appear dark green.

University of Florida. Citrus Tree Nutrient Series. https://edis.ifas.ufl. edu/topic_series_citrus_tree_nutrients University of Florida. Plant Nutrient Deficiency Database. http://hort.ufl. edu/database/nutdef/index.shtml University of Florida. Soil Fertility and Plant Nutrition. https://edis.ifas. ufl.edu/topic_soil_fertility_and_ plant_nutrition

Magnesium deficiency in citrus (pointed shape on older leaves).

January/February 2017

www.progressivecrop.com

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TREE NUTS

Emily J. Symmes, PhD IPM Advisor, Sacramento Valley

M

Photo Credit: J. E. Nay

any pests and pathogens require year-round activities in order to maximize the likelihood of achieving the low levels of harvest damage desired by growers, processors, and marketers. In order to realize these industry standards in almonds, walnuts, and pistachios, winter sanitation (removal and destruction of mummy nuts) is a vital component of your year-round IPM program.

The primary pest impacted by orchard sanitation activities in almond, walnut, and pistachio production systems is navel orangeworm (NOW).

Many years of research has shown that without the baseline of sanitation in an integrated NOW management program, even aggressive in-season spray programs may not be sufficient to keep damage below economic levels.

Reducing mummy nuts has a two-fold benefit: (1) Directly reduces overwintering NOW populations, and (2) Limits oviposition and development sites for the first generation of NOW in spring/ early summer.

The concept of sanitation for NOW management is not new. Research in the early 1990s by UCCE Advisor Steve Sibbett and Specialist Bob Van Steenwyk showed that increasing levels of walnut mummy destruction after removal from

the trees resulted in greater reductions in emerged NOW adults (Sibbett and Van Steenwyk 1993). Mummy nuts were placed on bare berm, in weeds, double-disked, or shredded. Over the two-year study, shredded nuts showed the highest levels of NOW reduction relative to those placed on bare berm (100 percent and 97 percent), followed by nuts double disked (95 percent and 68 percent), and nuts placed in the weeds (86 percent and 24 percent). In studies conducted in almonds from 2003 to 2006, Research Entomologists Brad Higbee (Wonderful Orchards) and Joel Siegel (USDA-ARS) demonstrated the relationship between the average numbers of tree and ground mummies and harvest damage in Nonpareils in the southern San Joaquin Valley (Higbee and Siegel 2009). Their research showed that to maintain kernel damage at harvest below 2 percent required fewer than an average of 0.2 tree mummies/tree and 4 ground mummies/tree after flail mowing. From this research, University of California IPM Guidelines were updated to reflect these more stringent almond sanitation thresholds for the southern San Joaquin Valley.

Current sanitation guidelines are most developed for almonds: Determine the average numbers of mummies per tree by mid-January, examining 20 or more trees per block.

Photo Credit: J. E. Nay

Winter Sanitation in Nut Crops

Photo 2. Multiple viable NOW larvae in the hull of a ‘Padre’ mummy.

Evaluate trees of all varieties, as numbers of mummy nuts can differ widely based on variety.

•

•

•

•

• • Photo 1. Multiple viable NOW larvae in a single ‘Monterey’ mummy nut.

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Progressive Crop Consultant

January/February 2017

If possible, determine the percentage of infested mummies and the presence of live larvae and pupae (Photo 1). This can provide additional information going into next season regarding the carry-over population, potential NOW pressure the following season, and blocks/orchards to keep a close eye on.

Trees should be cleaned to fewer than 2 mummies/tree (Sacramento and northern San Joaquin Valleys) and 0.2 mummies/tree (southern San Joaquin Valley) by February 1.

All varieties (not just Nonpareil) should be considered important for sanitation. Larvae can survive mild, dry winters in the hulls of hard shell varieties (Photo 2).

Shaking or poling after rain or fog events facilitates mummy nut removal, as the added moisture causes heavier mummies and weakens the attachment point.

Blow or rake all mummies into the middles and mow or disc by March 1.

In years with significant winter rainfall where ground cover is present, high levels of natural mortality may occur once mummies are on the

Photo Credit: F. J. A. Niederholzer

T R E´ C E´

Photo 3. Kernels of in-season nuts (three on right) and mummies (three on left) from Colusa County, CA in July 2015 following a dry winter. ground. However, in many locations and due to drought conditions in recent years, the “better safe-thansorry” approach should include destruction of mummies once they are on the ground. In dry years, the quality of mummy nut kernels can be maintained long into the following season and be an optimal food and oviposition source for NOW prior to the availability of in-season nuts (Photo 3).

In walnut and pistachio, the approach is similar, although specific mummy nut thresholds and guidelines are less developed. In walnuts, get the orchards as clean as is economically feasible by knocking mummies remaining in trees and destroying mummies once they are on the ground. The thicker shell of walnuts offers overwintering NOW more protection than the softer shell of almonds. Therefore, less natural mortality should be expected in walnuts, even in wet years, and mowing or discing walnut mummies should always be done regardless of weather conditions.

Pay attention to any areas surrounding the orchard where nuts or debris may accumulate and provide overwintering sites for NOW (e.g., around hullers, processing equipment, etc.). In pistachio, maximizing the time mummies are on the ground is important so they can begin to rot, leading to more NOW mortality. Destroying pistachio mummies is particularly challenging due to their size. However, discing pistachio mummies twice after removal from the tree can provide benefits by burying the nuts, thus limiting oviposition and development sites for the early season generations.

As labor costs continue to rise, some growers may begin to consider minimiz-

ing or eliminating orchard sanitation practices. It is therefore important to remember that removal and destruction of mummy nuts is not only critical for managing NOW, but may also provide benefit with regard to a number of orchard diseases. In pistachio and walnut, removal and destruction of mummy nuts reduces sources of inoculum of Botryosphaeria fungi. In almonds, inoculum sources of anthracnose, bacterial spot, brown rot, and possibly hull rot and scab (if hulls are infected) may all be reduced through mummy sanitation, leading to less disease pressure the following season.

Best wishes for a prosperous 2017!

The author can be contacted at ejsymmes@ucanr.edu.

PCC

References Higbee, B. S. and J. Siegel (2009). New navel orangeworm sanitation standards could reduce almond damage. California Agriculture 63(1): 24-28. http://ucanr.edu/repositoryfiles/ ca6301p24-65634.pdf Sibbett, G. S. and R. Van Steenwyk (1993). Shredding “mummy” nuts is the key to destroying navel orangeworm in winter. California Agriculture 47(5): 26-28. http://ucanr.edu/repositoryfiles/ ca4705p26-70062.pdf

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PEST MANAGEMENT

IPM Technology

Looking Back to Look Forward Sabrina Hill Contributing Writer

T

o the general public, the term “technology” conjures images of the latest gadget or computer program. The Oxford Dictionary defines technology as the application of scientific knowledge for practical purposes. In integrated pest management, that can take on many varied forms.

Jim Farrar is the Director of University of California Statewide Integrated Pest Management Program. He spoke at the California Association of Pest Control Advisors (CAPCA) 2016 Annual Meeting on pest control technology, and focused primarily on pest control trends over the last 20 years. In a later interview, he said it was a topic in which he was greatly interested.

“The message I was trying to get across at CAPCA was if you think of IPM strictly in terms of the goal being reduction in pesticide use, then the California Department of Pesticide Regulation data from its use reports shows that the aggregate reduction in use has not been that great over the last 20 years,” he said. “But, couple that with the fact that there’s been an enormous increase in the value of commodities produced in California. We’re producing a lot more agricultural value, at the same time as using a little bit less pesticides. I think that is incredible.”

Farrar pointed out in the last 20 years, there has been a big shift in the crops produced in California.

“If you think about the mid-90’s, cotton was still over a million acres.

Pistachios were just getting off the ground,” he said. “There has really been a shift toward higher value commodities in production ag in California. That shift is partially driven by the availability of water and partially driven by market forces. The fact that pesticide use has gone down slightly at the same time as this increase in value, I think is amazing.”

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The shift in crops grown around the state has led to other changes as well.

Farrar said pesticide use trends are partially driven by adoption of IPM and partially driven by regulations.

“If regulations restrict pesticides that had been commonly used, then there’s an IPM response. Now we’ve lost a tool that we used to use, so now what do we do in it’s place? So, there’s been a lot of advancement in IPM, partially because of good practice and partially in response to regulation,” he explained.

Changes in regulations can be a springboard to new advances in pest control, out of necessity.

“There is a lot of adaption going on in response to regulatory restrictions on some of the chemistries, for instance, chlorpyrifos and some of the fumigants.

Then, some changes to less toxic materials and having to deal with additional pests because of the less toxic chemicals are more narrowly targeted,” he said.

When asked if growers would need to use more chemicals because of those narrowly targeted formulas, Farrar explained it was a possibility. “It’s also possible to have multiple tactics. So, a using a pesticide plus some other tactic like rotation, cultivation, or changing the irrigation management, something like that.”

There are many other ways pest management technology is advancing as well. Farrar explained a biosolariation project.

“I think there’s a lot of potential there,” he said.

The project incorporates organic matter into the soil, which is then covered with plastic to solarize. He described it as a traditional solarization practice plus what happens biologically in anaerobic soil disinfestation. Soil solarization traps the sun’s heat and uses it to kill off pests. Anaerobic soil disinfestation was developed as an alternative to Methyl bromide fumigation in Japan and the Netherlands.

Farrar also discussed a research proj-

January/February 2017

ect out of Southern California involving nursery plants and shipping containers that are fitted with hot water showers.

“They put the plants in the shipping containers and turn on the hot water,” he explained. “It has to be hot enough for long enough, and, of course, they have to do the tests to make sure it doesn’t hurt the plants. They have to find that sweet spot to make sure the pests are killed but the plants are not damaged. The idea is to kill the insects, slugs, snails, and things like that before shipping the nursery plants out. It’s been used in Hawaii for several years and it’s fantastic. No chemicals, no residue, it’s safe for shipping, and good for preventing the spread of invasive pests.”

Another new development involves mechanical weeding and uses sensors along with computer software to make the process more automated. An electronic “eye” picks up certain images and colors and transmits them to the computer. The computer program then considers if the plant is in the seed line, is the right shape, and other considerations. If the computer rules it to be a weed, the machine uses a blade under the soil, like a hoe action, to kill the weed. There is a similar development in plant thinning that uses an herbicide, rather than the blade, to thin the crop.

Farrar said he is also excited about a recent addition to the Kearney Ag Research Center.

“Ag and Natural Resources just hired a new advisor, Alireza Pourreza, whose specialty is advanced technology around agriculture,” he said. “His PhD is from Florida and is in sensing. He was doing sensing of citrus diseases, such as HLB (Huanglongbing disease).

I’m really excited that he’s here to do that.”

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Continued from Page 18 detection sensor for HLB that picks up changes in starch levels in citrus leaves that reflect light differently from healthy leaves. It could lead to earlier detection, which would help prevent further spread of the devastating citrus disease.

Farrar said that kind of innovative thinking can be useful in many agricultural fronts.

“I’m really hopeful that he will get involved in integrated pest management around spray application technology,” he said. “The key being making sure that when we make a spray application, it’s on target, it’s effective, and it does what we need it to do.”

He said spray technology is due for some upgrades.

“We’re using some pretty old technology in spray applications, and there’s a lot of potential there for both improving the pest management that results from application and the environmental safety,” he continued. He said the result of bringing spray technology up to date would have a three-fold impact. “You get better control of the pests, less environmental impact and greater economical return to the grower.”

Looking toward the future, Farrar said another area that is ready for improvements is fumigation. He explained that when fumigants are used, they are used in large amounts per acre.

“They’re all on various important toxicity lists that the DPR has, and my feeling is that the regulators are going to be continuing to look at the chemicals that are on those lists,” he said. “Either we can try to get ahead of it and try to develop ways to manage with less, or develop ways to have alternatives so that we don’t need to use fumigants. I think that eventually either we’re going to need to move that direction or the regulators are going to push in that direction, and with good reason.”

In his CAPCA presentation, Farrar pointed out IPM is a method of reducing economic, human health, and environmental risks from pests and pest management strategies. He believes continued support for IPM research is necessary to address new invasive pests and changes in agricultural production systems.

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Progressive Crop Consultant

January/February 2017

TECHNOLOGY

UC Weather Information Cecilia Parsons Contributing Writer

U

sing a collection of weather data and models to make management decisions on pest and disease control can either save money on production costs or justify the expense of an application.

Lindsay Jordan, Univercity of California Cooperative Extension (UCCE) farm advisor for viticulture in Madera, Merced and Mariposa counties, said the web site www.ipm.ucdavis.edu/ weather is source of information and tools to calculate pesticide application timing for maximum effectiveness as well as many other important weather-related information. She noted that many growers and Pest Control Advisors (PCAs) find value in the historical data as they look and compare yearto-year pest and disease management decisions.

Scope of the weather data available from the University of California Integrated Pest Management (UC IPM) site includes daily air and soil temperatures, bulb temperature wet and dry, humidity, precipitation amount and kind; and leaf wetness duration. The site collects weather data from approximately 400 weather stations throughout California allowing for growers, managers and pest control advisor to make decisions based on conditions at specific sites. The California Irrigation Management Information System (CIMIS), which was developed by Department of Water Resources (DWR) and UC Davis, is a unit of the DWR that manages the automated weather stations in California.

The weather database stores current and past data. Current data are supplied by “automatic” “TouchTone” and “PestCast” stations. The automatic stations are microprocessor-based, part of the CIMIS Network operated

by California Department of Water Resources. These stations supply current daily values for several agriculturally important variables. DWR provides the information to UC IPM. TouchTone Page 22

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stations provide current weather data from agricultural locations. Volunteers record observations daily and transmit them to the UC IPM computer. PestCast stations provide current weather data monitored inside crop canopies in several research and extension networks. These stations also supply hourly or more frequent data that are collected automatically on a daily basis.

CIMIS was initially designed to help agricultural growers develop water budgets for determining when to irrigate and how much water to apply but the user base has expanded over the years. Current CIMIS data users include landscapers, local water agencies, fire fighters, air control board, pest control managers, university researchers, school teachers, students, construction engineers, consultants, hydrologists, government agencies, utilities, lawyers, weather agencies, and many more.

The number of registered CIMIS data users has also been growing steadily over the years. Currently, there are more than 40,000 registered CIMIS data users. This number reflects only those registered users that are primary users of the CIMIS data. All users that are registered with CIMIS and have access to the archived CIMIS data are considered primary users.

At a Grape Day 2016 presentation, Jordan demonstrated use of weather data in an IPM program for control of powdery mildew, a major concern for grape growers across California.

For Fresno, Madera, San Joaquin, Amador, Calaveras and El Dorado counties, UC IPM has linked data from weather stations in these counties to the Powdery Mildew Risk Assessment Index (PM RAI) created by the University of California, the index is based on daily temperature and life cycle of the fungus. The index is reported as a score with points added or subtracted depending on the temperature conditions. The total score can be used to determine when powdery mildew control is necessary. There is no substitute for field observation, Jordan noted, but

January/February 2017

combined with regular disease monitoring and fungicide rotation, the index is a useful tool for powdery mildew control.

The complete pest management guidelines and specific calculations for the PM for the powdery mildew Risk Assessment Index (RAI) is on line at the IPM site. There are also two models for monitoring two grape pests—the omnivorous leafroller and the orange tortrix. Selecting a weather station the accumulated degree-days can be calculated and used for these pest models.

Tools to assist with pest control decisions in alfalfa, a citrus thrips damage estimator, a plant parasitic nematode database and calculators for volatile organic compounds emissions for both fumigants and non fumigants can also be found on the IPM web site.

Additional tools on the UC weather networks site include a cotton planting forecast in March and April, chill hours accumulations from November through March, and sunset temperatures from February to May 15.

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