1a. Objectives (from AD-416)
To monitor natural enemy densities of key moth pests in orchards with and without navel orangeworm mating disruption. Initial studies will focus on the moth pests and natural enemies found in almonds, pistachios, and walnuts, which have the greatest potential for change.
1b. Approach (from AD-416)
Navel orangeworm (NOW): Goal is to compare changes in NOW parasitism levels at three critical periods: (i) after the first NOW summer generation (ii) at harvest time, and (iii) during the overwintering period. At each site, a minimum of 1000 nuts will be collected and dissected for NOW or parasitoids. Peach Twig Borer: The peach twig borer adult flight periods will be monitored using pheromone traps. PTB larval infestation will be monitored at three critical periods: (i) during spring (ii) at harvest time, and (iii) during the overwintering period. Nuts will be collected to determine levels of infestation Oriental fruit moth: The oriental fruit moth (OFM) adult flight periods will be monitored using pheromone traps. OFM larvae will be collected to determine infestation levels and parasitism in a similar manner as described for PTB. Leafrollers: Populations of leafrollers including obliquebanded leafroller (OBLR), fruittree leafroller (FTLR), the filbertworm (FW), and omnivorous leafroller (OLR), will be assessed over the next 3 years, in the NOW mating disruption program. The species of moth and their infestation levels will be determined for the three regional areas of the NOW mating program. A color brochure will be developed that provides a picture key, along with some field taxonomy guides, to identify the different secondary moth larvae. A brief description of their biology and control will also be provided.
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. Changes in navel orangeworm parasitism levels in almonds at three critical periods: (i) after the first NOW summer generation (ii) at harvest time, and (iii) during the overwintering period at two sites were monitored in Fresno County and in Kern County. Nuts were dissected for navel orangeworm or parasitoids. The peach twig borer is another important pest of almonds and in some counties it rivals navel orangeworm in importance. The peach twig borer adult flight periods were monitored using pheromone traps. Larval infestation was monitored at three critical periods: (i) during spring (ii) at harvest time, and (iii) during the overwintering period. The oriental fruit moth is a secondary pest of almonds and it population may increase as fewer insecticides are used to control navel orangeworm. Almonds were collected to determine oriental fruit moth infestation and its adult flight periods were monitored using pheromone traps. Larvae were collected to determine infestation levels and parasitism. The level of parasitism of each of these moth pests and their infestation levels in almonds were determined for the Central and Southern San Joaquin Valley. At this time, mating disruption has no effect on the populations of these two secondary pests. Progress was monitored by attendance at stakeholder meetings, site visits and conference calls.