During the past year, UC IPM Advisor Walt Bentley has made further progress in managing pests of fresh market peaches, nectarines, and plums in the Central Valley by introducing growers to various management methods.
Monitoring techniques have been improved and thresholds established for the need to apply insecticides for such pests as San Jose scale, oriental fruit moth, webspinning spider mites, and forktailed bush katydid. This has been made possible through a grant with the California Department of Pesticide Regulation and Region 9 of the U.S. Environmental Protection Agency. The California Tree Fruit Agreement has also been a close partner in this program.
Techniques such as mating disruption, which involves using a chemical mix that mimics a sex pheromone that females release to attract males, is an effective method for oriental fruit moth. Males follow this pheromone trail to find the female. The more pheromones released into the area, the more confused the males become in picking up the scent, and the chances of mating are reduced.
In addition, Bentley has advised growers on horticultural mineral oils application for San Jose scale and European red mite, and selective insecticide application for peach twig borer, omnivorous leafroller, and forktailed bush katydid. These methods have allowed farmers to manage their pests while reducing the chances of contaminating the environment.
Results have been impressive. Mating disruption has also allowed for the reestablishment of the oriental fruit moth parasite Macrocentrus ancylivorous. Late-season parasitism, where one organism lives as a parasite on another, has reached levels of 80 to 90 percent in some orchards, reducing the number of oriental fruit moths the following year.
This pest management approach is described in the ANR publication 21625, Seasonal Guide to Environmentally Responsible Pest Management Practices in Peaches and Nectarines. The publication was made possible through funds from the EPA grant and is free to farmers.
Cooperating farmers Ty Parkinson and Bill Chandler from Reedley, California, have led the way in demonstrating the approaches outlined in the guide. These cooperators will also be using new spray application equipment known as “SmartSpray.” This sprayer uses a sonar mechanism to turn off nozzles when there is no tree target. It greatly reduces the amount of spray being applied during the dormant and bloom season, when no leaves are present on the tree. Savings of up to 40 percent in material have been demonstrated in tests with the sprayer. The technology is available on new machines, or growers can retrofit older sprayers.
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