1a. Objectives (from AD-416):
Reduction of unnecessary insecticide application by improving predictability of navel orangeworm abundance and damage.
1b. Approach (from AD-416):
We will examine the association of navel orangeworm damage to Nonpareil almonds, before and during harvest, with trap data. The research will be conducted in organic orchards to minimize grower insecticide input as a confounding factor. Traps examined will include pheromone traps (with unmated females as a pheromone source), and grid traps with ovipositional attractant targeting eggs and females. Association of monitoring with infestation autocorrelation of later infestation with earlier preharvest samples will be examined using generalized linear models.
3. Progress Report:
Progress was made on objective 4C (Develop models for almonds relating damage to males captured in pheromone traps within the same year) of the parent project. The navel orangeworm is the principal pest of almonds. Organic almonds offer an important research opportunity because they have fewer pest management alternatives, and because they have a greater range of damage from navel orangeworm. In this study, experiments were performed to: 1) compare damage prediction between traps for males, females, and eggs; and 2) characterize a newly-released artificial pheromone lure. In the first experiment, counts were compared between pheromone traps for males (using unmated females as a pheromone source), eggs captured in traps with ovipositional attractants, and females capture in traps using the same ovipositional attractants as for eggs. The number of females captured correlated significantly with the number of males captured but not the number of eggs captured. However, trapping for males had practical disadvantages and, since a synthetic pheromone lure for navel orangeworm became available during this time, subsequent work examined practical use of this lure. An experiment comparing the number of males captured between lures and trap types found similar number of males captured in wing traps baited with either unmated females or synthetic pheromone lures, but significantly fewer males captured in either bucket traps or delta traps baited with the synthetic lure. A third experiment is currently underway to examine the impact of mass trapping of males on the number of males captured in traps baited with unmated females.