Copper Deficiency in Pistachio

Copper is a micronutrient of plants. In certain situations, soil levels may be low enough or plant growth demand high enough that deficiency may occur. Within pistachio, this deficiency often occurs in the middle of the season (July-August) on young, fast growing trees. Symptoms include the die-back of new growth, forming a “shepherd’s crook.” Most, if not all, new growth will show this deficiency. In these cases, a foliar spray containing copper can help remediate the deficiency. Ideally, deficiency should be prevented to maximize growth. To prevent copper deficiency, plan to apply 0.1 lb/acre or 0.100 kg/ha of a chelated copper as a foliar spray when the new canopy is 50-90% expanded. This spring-time application will prevent the symptoms from occurring later in the summer. Soil applications should also be considered if soil values are low. Cooper sulfate can be fertigated in acidic soils, while a chelated product (EDDHA, or similar) should be used in alkaline soils. Soil applied rates of 1-2 lbs/acre or 1-2 kg/ha should be sufficient.

May 30, 2020

Verticillium Wilt of Almond (and Pistachio)

The high heats of late spring/early summer can bring upon the onset of wilts. Verticillium wilt, a common occurring wilt, is caused by the fungus Verticillium dahliae Klebs. V. dahliae is widespread in soils throughout the county, with susceptible hosts in a large number of perennial and annual crops. Within perennial crops, almond and pistachio are susceptible hosts. Leaves turn light tan and die, and often remain on the tree. In some cases, particularly in pistachio, symptoms develop slowly over several years causing a thinning of the leaves and a corresponding loss in yield as the fungus progresses up the branch. Internally, the xylem wood turns dark, and a cross section will show a ring of discolored tissue. This darkened tissue will extend down the affected scaffold to the point of origin within the root system. Several scaffolds of the tree may be involved if the pathogen infected a large portion of roots. The fungus survives in the soil within survival structures known as microsclerotia. It enters the trees through the roots, infecting the xylem tissues of the plant. Upon infection, the fungus produces a dark pigmented substance that clogs the xylem tissues, preventing the upward flow of water to the scaffold branches. When the affected branches or leaves demand more water than it can receive due to the blockage, it collapses. Cool springs and wet soils favor disease development. The fungus is eliminated from the above-ground portions of the trees during the hot weather. The fungus may survive within the root and reinvade the upper part of the tree, but it is thought that repeated occurrences of wilt are caused by new infections each year. Within almond, young trees within their 2nd and 3rd leaf are the most susceptible to tree loss. All almond rootstocks and varieties are susceptible,

May 14, 2016

Kaolin Clay May be Useful in Increasing Chill Accumulation in Pistachios

David Doll, University of California Cooperative Extension, Merced, CA; Clay Beck and Joe Coelho, Valley Orchard Management, Three Rocks, CA. A preliminary study conducted by the University of California Cooperative Extension and Valley Orchard Management in which Surround® was sprayed onto dormant pistachio trees has shown an increase in cluster count and yield. This technique may be useful in increasing chill unit accumulation by 5-7 portions in winters with minimal fog and high amounts of sunshine. Over the past two years, pistachio orchards have shown classic low chill symptoms, which include weak, delayed, and protracted bloom, poor overlap with males, and weak leaf-out. This can lead to a severe reduction in yield due and high blanking due to poor pollination. Chill is weather related and a function of temperature and time. In cool, cloudy weather, chill portions accumulate quickly as temperatures stay within the ideal range of 33° and 54°F. When temperatures are below or above this range, chill units do not accumulate and could be subtracted if the temperatures are too high. This means that during warm, sunny weather during tree dormancy, chill portions do not accumulate, and if too warm of weather, negation of earlier accumulated chill occurs (For more information please see: https://thealmonddoctor.com/2015/01/13/chill_portions_model/). Chill units are calculated using ambient air temperatures. This may be inaccurate, however, due to the temperature of the wood. In sunny weather, wood is usually warmer than the ambient air temperature due to radiant heat, while in cloudy weather, the wood temperature matches ambient air temperature. With this consideration, sunny weather may increase wood temperatures above the ideal range, negatively impacting the accumulation of chill. In attempts to increase chill unit accumulation in the winter of 2014-2015, several applications of Kaolin clay (Surround®) were made to a ‘Kerman’ with ‘Peters’ pistachio orchard located

October 26, 2015

Carpophilus Beetle: What We Know

Authors: David Doll and Zubair Shahzad Carpophilus beetle (Carpophilus truncatus) is a small insect that causes severe damage to almond kernels. The insect overwinters within the soil, and emerges infesting the almonds at hullsplit. They are quite mobile and able to fly up to 3 miles/5km to find a suitable host. Humid conditions increase the emergence and rate of development, leading to multiple generations within a season. More on Carpophilus beetle can be found here. Damage is highly dependent on the variety, harvest timing, and weather conditions. Soft-shell varieties with poor shell seal are most susceptible. Within Australia, the worse damage is reported on Nonpareil, with minimal damage reported on Monterey, Price, and Carmel. Infestation rates increase when harvest delays occur as the nuts are exposed to multiple generations. Rain between hull-split and harvest often increases damage as it results in a faster rate of insect development and harvest delays. Effective management depends on both chemical and cultural practices. In severely infested fields, operations have reported success of applying clothianidin at 1% hullsplit. Early harvest has been shown to reduce exposure and corresponding damage. Nonpareil harvest completion should be targeted by the end of August in the northern hemisphere/February in the southern hemisphere. Winter sanitation is critical to reduce Carpophilus beetle populations. Mummies serve as the initial food source for the beetles as they exit the soil. Operations should target <5 mummies per tree after sanitation. Nuts should be destroyed as soon as possible after winter shaking as the beetle emerges from the soil as it warms. Current trapping methods do not have a lure specifically for C. truncatus. General lures for Carpophilus beetles are available and can be used within bucket traps. Although not providing species level population dynamics, it can provide insight on the emergence of carpophilus beetles

November 18, 2023

Others

Posts covering a wide range of topics, including field observations, other crops, and technology. Technology: Field Notes: Other Crops:

February 19, 2023

Technology Corner: Q&A with Semios

EDITOR’S NOTE: This entry is part of an ongoing series to highlight a new technology related to almond and tree nut production. The question/answer format is set to focus more on the technical aspects and application of the technology. I would like to thank James Watson from Semios who took the time to answer my questions regarding their irrigation monitoring platform 1. Semios is a platform that links in a variety of sensors using IoT and on-farm networks. These sensors provide data for on-farm decision support. They include water monitoring tools, pest management tools for insects, and weather sensors. Would you be able to briefly describe the mission of Semios and how it works to integrate these various sensors? Semios subscribes to the philosophy that granular, in-canopy climate is the fundamental element of key crop decisions made by growers whether it’s the development of insect and disease pressure or water requirements of the plant. For this reason, the Semios solution always incorporates methods for monitoring climatic conditions at a granular level with the goal to optimize all resource inputs for the best possible crop result. Semios has developed a configurable platform approach in response to growers telling us how they want their agtech experience simplified. They don’t want to be buried in data or have to log into many different systems to get the information they need to make a decision. By bringing these important elements together into one streamlined system, Semios gives growers a holistic view of the information that informs their key crop management decisions. 2. Please describe the basic hardware and sensor systems utilized within the platform. The basic Semios offering includes at least one out-of-block weather station and, depending on acreage, one to many in-block weather stations tracking the core climatic conditions of the orchard. These stations

February 25, 2021

Technology Corner: Q&A w/ Phytech

EDITOR’S NOTE: This entry is part of an ongoing series to highlight a new technology related to almond and tree nut production. The question/answer format is set to focus more on the technical aspects and application of the technology. I would like to thank Mark Sherfy from Phytech who took the time to answer my questions regarding their irrigation monitoring platform. Phytech is an irrigation technology that monitors the tree’s water stress. Please describe the basic hardware system and software analysis that is behind Phytech’s irrigation management technology. Phytech has several different sensors in the field and each sensor has an important role to play in the overall puzzle. We are about understanding exactly what the tree needs and what it is feeling. The ‘bread and butter’ of our organization is our dendrometers, but we also have several other sensors such as water pressure, soil moisture probes, fruit sensors, frost sensors and loggers. By using all these sensors, we can give the grower daily irrigation recommendations and we display an intuitive color scheme that helps the grower understand the current plant status of the orchard. On top of this, we have just launched an analytical section on our website that displays all the season’s data in one area. This displays such things a heat maps, bar and line graphs over different periods of time. Varieties, blocks, and ranches can also be compared to see where adjustments need to be made. It is a tool that gives growers instant recommendations daily, but it’s also an analytical tool that can change the grower’s overall strategy. What crops have been successful in utilizing Phytech’s products? Quite a long list of crops. We have been extremely successful in the almond industry as we have found out that the ETc is not only different per orchard,

January 31, 2021

Technology Corner: Spear-Lep w/Vestaron

EDITOR’S NOTE: This entry is the first in a new and (hopefully) ongoing series to highlight new technology related to almond and tree nut production. The question/answer format is set to focus more on the technical aspects and application of the technology. Since we are approaching hull-split, I thought a reasonable place to start would be with Vestaron, a company which recently released a new class of insecticides.Thanks to Noel Cornejo for taking the time to answer my questions. Question (Q): Spear-Lep is a new group of insecticides that has been shown to be effective on lepidopteran pests, such as peach twig borer, codling moth, and navel orangeworm. What is the active ingredient and how does this product work? Answer (A): The active ingredient is an insecticidal peptide called GS-omega/kappa-Hxtx-Hv1a. It was carefully optimized to target the nicotinic acetylcholine receptor in the insect nervous system, but at a receptor site distinct from Spinosad and neonicotinoids. The end result is paralysis of the lepidopteran larvae that ingest it. Q. Is this product directly toxic to insect pests? Or does it have to be consumed? How is the activity on developing larvae (may have been answered above)? A. For lepidopteran pests Spear works through ingestion. Extensive studies confirm activity against neonates as well as later instars of all species tested to date. At high v/v concentrations, Spear works though topical contact against smaller, soft-bodied pests such as mites, thrips and whiteflies. Q. How is this product different from what is currently on the market and is there any efficacy data comparisons among the various products on the market?  A. This novel class of insecticidal peptide is the first of its kind. Identified in nature, and then optimized painstakingly in the lab, Vestaron’s peptide insecticides are designed to target neuromuscular receptors proven through

June 28, 2020

Put Leaffooted Bug Monitoring on Your To-Do List

Written By Kris Tollerup, UC IPM Advisor for the San Joaquin Valley Unlike many of the moth pests, we do not have an effective lure that acts to attract leaffooted bug (LFB) to a monitoring trap of some sort.  An LFB lure could be used in almond beginning at mid-March for detecting the pest when they first begin moving into the crop.  Unfortunately, development of a lure remains elusive; researchers out of the University of California, Riverside have worked on the issue for several years now.  They have recently identified compounds used by LFB for sexual and aggregation communication, but synthesis of the compounds has proven quite difficult. This means that good-old visual scouting provides the only viable option.  About this time (mid-March – early April) leaffooted bug begin moving into almond from their overwintering sites.  A caveat to this is that the recent cool weather may have slow their movement and caused some individuals to re-aggregate.  For instance, during early March, we observed signs that LFB had begun to disperse from overwintering sites; however, stopped short and reformed aggregations on nearby citrus trees.  This likely occurred due to cool, wet weather. With warmer weather certainly coming soon, begin monitoring in locations that historically have sustained damage and notably locations near pomegranate and riparian areas.  The bug typically prefers the sunny side of the tree and will rest on nuts on the outside area of the canopy.  Take about 15 seconds to visually inspect about 100 nuts per tree; monitoring 15 to 20 trees in a 5 to 10-acre area. Moreover, the University of California, Pest Management Guidelines recommends monitoring by examining nuts on the ground and in the tree for gummosis.  Keep in mind that gummosis from LFB or other stink bug feed appears clear while gummosis from other

April 5, 2018