1a.Objectives (from AD-416):
1. Survey organic orchards on predator release practices
2. Develop methods to allow differentiation between released and naturally occurring predators
3. Develop methods to optimize release methods
4. Conduct laboratory trials to compare efficacy of reared and released species
1b.Approach (from AD-416):
Organic apple growers will be surveyed to determine extent to which insectary reared natural enemies are released as components of biological control programs in orchards. We will develop molecular methods allowing us to differentiate among field-collected predators originating from releases versus naturally occurring populations. Tests of release efficacy will be done by comparing pest and predator densities in areas of the orchard receiving releases and areas in which no releases are made. Field trials will be done to assess how release methods (numbers released, timing of releases, stages of predator released, method of release) influences efficacy. Laboratory trials will be done to confirm that insectary-reared predators feed and develop on target pests.
Best practices for predator releases: lacewings, beetles, and mites.
Spring aphids represent a difficult pest problem in organic apple and cherry orchards because there are no organically approved pesticides for these pests. ARS entomologists at the Yakima Agricultural Research Laboratory are developing methods to spray the egg stage of lacewings, a key group of predators of aphids, or to trees early in the growing season to reduce fruit damage by spring aphids. Spraying eggs in water based solutions has proved poor at adhering to trees. Current research compared methods to apply eggs in nontoxic foams using various sprayer designs. Foam carriers showed much better adhesion to trees at contact and good longer term retention in the absence of high winds or rain. The work reported here addresses objectives 1 and 4 of the parent project plan.