2012 Annual Report 1a.Objectives (from AD-416): To validate and demonstrate areawide management approaches, primarily mating disruption, for the control of navel orangeworm in walnuts grown in the northern region of California’s central valley. 1b.Approach (from AD-416): Management of navel orangeworm in walnuts is predicated on effective suppression of codling moth because this insect provides an opening for early season entry of navel orangeworm. A large-scale effort to use codling moth pheromone to disrupt mating will provide the basis for an indirect non-insecticide management option for navel orangeworm control. Additionally, smaller sub-plots will be treated with a pheromone mating disruption program directly targeting navel orangeworm. As part of this project, movement of navel orangeworm among the different host crops in the Sacramento Valley/north region (primarily walnut and almond) will be assessed in order to determine the parameters that determine success for mating disruption targeting navel orangeworm in walnuts. Part of this research will be conducted in collaboration with a scientist at the University of California, Agriculture and Natural Resources in Yuba City, California, another participant in this areawide project. 3.Progress Report: This Specific Cooperative Agreement was established to support objective 1.A of the in house project and is related to the management of the navel orangeworm in tree nut crops. The efficacy of mating disruption targeting the codling moth was evaluated in the Sacramento Valley. Management of navel orangeworm in walnuts is predicated on effective suppression of codling moth because this insect provides an opening for early season entry of navel orangeworm. A large-scale effort to use codling moth pheromone to disrupt mating provides the basis for an indirect, non-insecticide management option for navel orangeworm control. In addition, smaller sub-plots were treated with a pheromone for mating disruption program directly targeting navel orangeworm. The area covered by each puffer dispensing the navel orangeworm pheromone was calculated in order to optimize mating disruption and determine if a small number of puffers can be used in this program. Currently, mating disruption is most effective when two traps per acre are used. This density may be lowered in the interior of large orchards to 1 trap per acre, depending on the pressure coming from the orchard edge.