1a. Objectives (from AD-416):
To validate and demonstrate areawide management approaches for the navel orangeworm in tree nut crops grown in the northern region of California’s central valley.
1b. Approach (from AD-416):
In collaboration with USDA-ARS scientists at the San Joaquin Valley Agricultural Sciences Center, Commodity Protection and Quality Unit, we will work with stakeholders in the Sacramento Valley to validate and demonstrate navel orangeworm management spproaches including cultural controls (sanitation, destruction of ground mummies, andearly harvest), improved timing of reduced risk insecticides, and mating disruption. In order to successful accomplish this, we will validate and modify parameters (if necessary) for risk assessment in northern tree nut growing regions of California including navel orangeworm overwintering survival in mummy nuts remaining on trees and on the ground, contribution of nearby navel orangeworm sources to load in commercial orchards, incidence of navel orangeworm damage in the presence of other kernal feeders, and navel orangeworm degree-days.
3. Progress Report:
This Specific Cooperative Agreement was established to support Objective 1A of the in house project and is related to the management of the navel orangeworm in tree nut crops. Navel orangeworm is the most destructive lepidopteran pest of almonds and pistachios in California. One of the challenges in controlling this pest is understanding the conditions that allow populations to survive the winter, so that areas with potentially high populations can receive additional monitoring to prevent damage. Navel orangeworm management approaches including cultural controls (sanitation, destruction of ground mummies, and early harvest) and improved timing of reduced risk insecticides for almonds in the Sacramento Valley were validated and demonstrated. In 2009-2012, navel orangeworm overwintering survival in mummy nuts remaining on trees and on the ground was evaluated. This research established that Manteca was the upper limit for navel orangeworm survival in nuts lying on the ground and further north, a combination of almonds rotting on the ground and bird feeding eliminated the nuts left on the ground. This research demonstrated that sanitation standards can be less stringent in the Sacramento Valley because of the combined effect of increased rotting and nut removal by birds. Sanitation must be more stringent in the San Joaquin Valley because of the reduced rainfall.