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United States Department of Agriculture

Agricultural Research Service

Research Project: Impact of navel orangeworm mating disruption on the natural enemy complex of key arthropod pests

Location: Commodity Protection and Quality

2013 Annual Report


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 1A of the in house project and is related to the management of the navel orangeworm in tree nut crops. We compared changes in navel orangeworm (NOW) 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. Two sites were monitored, one in Fresno County and the other in Kern County. Nuts were dissected for navel orangeworm or parasitoids. 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 its population may increase as fewer insecticides are used to control navel orangeworm. Almonds were collected to determine levels of infestation of Oriental Fruit Moth. Adult flight periods were monitored using pheromone traps. Larvae were collected to determine infestation levels and parasitism. Parasitism level was very low throughout this study. Predator levels were not affected by mating disruption. Most importantly, mating disruption has no effect on the populations of these secondary pests, and will help support adoption of this new technology. Adoption of mating disruption will reduce reliance on insecticides and improve almond quality.


Last Modified: 10/21/2014
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