Issue link: https://www.e-digitaleditions.com/i/1123864
4 A L M O N D O R C H A R D 2 0 2 5 G O A L S PEST MANAGEMENT Continued from Page 3 If monitoring reveals the presence of spider mites, assessments need to be made of predators that naturally control them. "The most important 'beneficial' to look for is sixspotted thrips, which feed primarily on spider mites and can manage or lower mite populations," Haviland said. In recent trials conducted in growers' orchards, Haviland and his team found that if there were three thrips or more per 3" x 5" sticky strip trap each week, those thrips were likely to keep the mite population from drastically increasing. "If thrips are present," said Haviland, "there's a 50% chance that mite populations will be either the same or lower in 14 days." This means that to allow natural predators to take care of these mites, growers should not use prophylactic miticide treatments in May. If, after monitoring both mite and thrips populations weekly growers and their PCAs determine treatment is necessary, then they can consider using a miticide with oil, opting for an application that doesn't disrupt the predators and reduce the efficiency of this biocontrol option. For NOW, precision is key to efficient sprays Crop protection against NOW also requires monitoring during hullsplit. Last winter, growers should have properly sanitized their orchards and, starting in late spring, growers may have deployed pheromone mating disruption to reduce NOW populations. To note: a key principle of IPM involves minimizing the potential for a pest problem through prevention. With hullsplit approaching, growers need to work with their PCAs to determine if hullsplit sprays are needed, and to nail down the appropriate timing and number of hullsplit sprays to reduce crop damage due to NOW. Decisions regarding which insecticides to use for NOW should be made after assessing the potential risks of the compound to beneficial organisms and environmental quality, as some materials used to control NOW decimate the thrips that control the mites, even into the following growing season. For effective hullsplit sprays for NOW control, growers should keep three key factors in mind as they prepare to make applications: timing, calibration and speed. Timing: Timing should coincide with the beginning of hullsplit and with the beginning of NOW's second flight. It's essential that the first spray (if multiple are needed) is complete no later than at 1% hullsplit. 2 To predict the onset of hullsplit, growers should reference the Almond Hull-Split Prediction Model, created by Ted DeJong from the Department of Plant Sciences at UC Davis. Calibration: It's important that sprayers are set up properly so that each application reaches the top level of the trees while also minimizing spray drift. Speed: Growers and applicators need to go the proper speed — a recommended 2 miles per hour — to ensure better coverage in the orchard. In addition to these factors, growers and applicators should apply the proper volume of spray material to ensure full coverage. Research funded by the Almond Board of California (ABC) and others "Understanding the interactions between growing practices on key almond pests is key to maintaining an IPM program." – Gabriele Ludwig Pheromone traps are an effective way to monitor for navel orangeworm in the orchard.