Ask the Expert: Be Prepared for Heavy NOW Pressure in Pistachios
By Jeff Pacheco, Technical Sales Agronomist, DuPont Crop Protection
Q: With three consecutive drought years in California, heavy navel orangeworm (NOW) pressure is anticipated. Are any management changes recommended ? A: Without relatively cold, wet winter weather to accelerate pistachio mummy breakdown and decomposition, NOW pressure remains at the high level experienced during the past few years. This season’s warm spring has accelerated degree days (DD) and pistachio development, which may lead to more extended harvests and possibly an additional NOW generation. Depending on NOW pressure in orchards and the number of shakes anticipated, USDA-ARS Research Entomologist Dr. Joel Siegel recommends using at least three spray timings at 1,700, 2,200 and 2,700 DD from January 1 to achieve effective NOW control. A fourth generation of NOW may require an additional application at approximately 3,200 DD. For resistance management, it is very important to rotate insect control products from different insecticide groups to avoid treating successive generations of NOW with the same mode of action insecticide. This recommendation extends to adjacent orchards of almonds and pistachios, since NOW populations may move between them. Since early hull-split applications in almonds typically occur around, or overlaps with, the 1,700 DD stage in pistachios, treating both crops with the same product during this timeframe helps growers avoid exposing successive NOW generations to the same insecticide group, which could potentially lead to resistance development. For optimum control, it’s always best to treat NOW early in the pests’ life cycle to reduce the build up of populations and to protect nuts as the season progresses, so growers can maximize yield potential. DuPont™ Altacor® insect control powered by Rynaxypyr®, an anthranilic diamide (Group 28) insecticide, is an effective, long-lasting management option for NOW in rotation with products from other insecticide groups. Altacor® provides ovicidal1, ovi-larvicidal, larvicidal and adult activity2,3 on NOW for contact, ingestion and extended residual control. While Altacor® is strong on NOW, it is soft on predators and parasitoids, and therefore will not flare mites. Altacor® offers a short 10-day preharvest interval for greater flexibility and utility with extended harvests. Altacor® may be applied at a rate of 3.0 to 4.5 ounces per acre up to a maximum of 9.0 ounces per acre per year. With heavy NOW pressure, the 4.5-ounce rate is recommended for best results on all life stages of NOW. To achieve adequate spray coverage, apply Altacor® with 100 to 200 gallons of water per acre and keep sprayer ground speed at 2 miles per hour or slower. Growers should talk to their DuPont representative or pest control adviser for the best recommendation for their acres.