David Doll0 commentsJune 28, 2020Insects, Technology

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

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David Doll6 CommentsJanuary 19, 2018Horticulture, Insects

How late can almonds be shaken for winter sanitation?

Winter sanitation is critical in managing navel orangeworm (as well as some other diseases) within almonds. Removing this past year’s remaining almonds – also known as mummies – is a time intensive process. Sanitation occurs by winter poling crews or by re-shaking the trees. This “winter-shake” is a quick way of removing the majority of the mummy nuts and, in high mummy-count orchards, is often used in combination with poling crews. With a dry November and December, winter-shaking of almonds have been delayed. This has led to several questions regarding how late almonds trees can be shook. Work done over 35 years ago by Steve Sibbett and colleagues found no impact on nut set, yield or size when winter shaking as late as January 31st. This was approximately 8 days prior to pink bud. The author concluded that shaking should be concluded by January 25th within the southern San Joaquin Valley, while it could be a week later in later blooming areas. Cited article: http://calag.ucanr.edu/archive/?type=pdf&article=ca.v037n07p20 When winter-shaking, it is common to see buds on the ground. Even though there may be several hundred buds, a reduction of yield shouldn’t be expected. This is due to the large number of buds that are present on an individual tree. For example, in a 3000 lb/acre mature orchard with 140 trees/acre, approximately 40,000 buds are on each tree, based on a 25% fruit set. Even if substantially higher buds drop from the tree after shaking, observations from several researchers suggest that the tree would compensate with a higher set percentage. Being that this research is over 30 years old, there is a need to update the work. Modern shakers are more effective as well as adjustable. It may be possible to shake closer to bloom without effect (although 8 days prior to pink

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David Doll0 commentsJuly 28, 2016General, Horticulture

Stockpiling Almonds During Harvest

With the increase in almond plantings over the past few years, processing delays will become more common. While waiting to be processed, almonds are usually stockpiled. Stockpiling has a number of advantages,  including getting the almonds out of the orchard sooner to allow the ability to perform  post-harvest practices, reduce in-field insect infestations, and allowing greater flexibility in scheduling transport to the processor. When stockpiling, make sure that the total moisture content (In-hull almond) is less than 9%  (Hulls should snap when bent). Choose a location which is suitable for drainage in rainy weather and that is not near equipment or fuel storage.   Stockpiles should be oriented in a north-south direction to aid in drying and covered with white-on-black tarps. These practices reduce humidity and day-to-night heat fluctuations, leading to a reduction in condensation. Monitor humidity and open the tarp when appropriate to reduce condensation and mold formation. Also monitor  and treat for  insect, bird, and rodent pests. If rain threatens, ensure piles are covered . Finally, be aware that stockpiles are a potential fire hazard. Stockpiles should be fumigated to reduce insect infestation. NOW is an excellent storage pest and can survive in stockpile conditions. Furthermore, this pest can continue to feed and reproduce within stockpiles, increasing damage as well as aflatoxin risk. Although time consuming, fumigation is critical in killing larvae and eggs, reducing damage. Finally, be wary of too much moisture in stockpiles. Studies have shown that hull moisture above 14% and a holding temperature greater than 120°F will increase the risk for concealed damage, mold, and aflatoxin. With an earlier harvest, stockpiles will be exposed to higher temperatures. If needed, delay harvest until nuts can dry. This will be increasingly necessary as orchard canopy coverage increases as cooler temperatures and more shade increases dry times. Avoid

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David Doll5 CommentsJuly 1, 2016Insects

Airblast v/s Electrostatic Rigs: Is there a Difference?

Hull-split sprays have began across the southern valley. These sprays are made to protect the crop from the infestation by Navel Orangeworm (NOW). During this time, it is common to receive questions regarding spray coverage. A common question received is about the comparison of electrostatic versus air-blast sprayers. A spray trial was conducted at the Nickels Soil Lab near Arbuckle, CA to compare the coverage and NOW control of an axial fan/air-blast and electrostatic spray rig.  Sprays were applied between 9:30 – 11:45 PM, when temperatures were below 75oF and relative humidity above 65%, to minimize evaporation and maximize spray coverage.  The replicated trial consisted of three treatments: Axial fan, air-blast sprayer (John Bean Spraying Co., 500 gallon tank, 36” fan, PTO driven; 143 gpa, 1.75 MPH, 170 psi system pressure) Air-shear, air-blast sprayer with electrostatic droplet charging (Progressive Ag, Model 2250, PTO driven; 50 gpa; 3.3 MPH and 30 psi system pressure). Air-shear, air-blast sprayer without electrostatic droplet charging (Progressive Ag, Model 2250, PTO driven; 50 gpa; 3.3 MPH and 30 psi system pressure). Eighth leaf ‘Fritz’ trees were sprayed with Delegate WG insecticide at hull-split timing. Applications included a molybdenum tracer to help determine spray deposition. Results: The spray coverage and NOW control results from the study (1 Day After Treatment) can be found in the table and summarized into four points. Sprayer Treatment Hull Mo Deposition – Upper canopy (15-20 ft) % NOW survival Upper Canopy (15-20 ft) Hull Mo deposition – Lower Canopy (5-7’) % NOW survival Lower Canopy (5-7’) Standard Axial-Fan/Airblast Sprayer 0.06 a 1.64% a 0.09 a 0.19% a Electrostatic Sprayer with electrostatic charge 0.05 a 3.20% b 0.18 1.01% b Electrostatic Sprayer w/o electrostatic 0.07 a — 0.15 b – Different letters indicate different statistical groupings at p<0.05. -Results pooled with those from

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