Project Number: 5352-22000-017-29
Project Type: Reimbursable

Start Date: Mar 30, 2007
End Date: Dec 31, 2007

Objective:
The project objectives are to develop an effective lure for Washington apple maggot flies based on discrimination of host fruit odors. 1. We will collect large numbers of apple maggot pupae from western Washington and rear them to the adult stage for tests using attractants in the laboratory. 2. We will use traps baited with hawthorn and apple volatile blends, and possibly other blends such as dogwood, snowberry, or blueberry, in areas of central Washington to monitor populations on black hawthorn, and in areas in western Washington and the Columbia Gorge that have fly populations on apple and hawthorn. 3. We will compare the behavioral responses, in a flight tunnel, of apple maggot from Washington and New York to odorants already identified from apple and eastern hawthorn fruits, as well as volatile blends that we have identified, which may include those from flowering dogwood, blueberry, and snowberry fruit, all of which are infested by different Rhagoletis host races or species.

Approach:
Objective 1. Collection of flies. The availability of large numbers of Washington apple maggot flies is vital for this project, so a large amount of effort will be placed on collecting flies for experiments. Apple maggot pupae have been collected in anticipation for tests in 2007. In addition, in June, July, and August 2007, soil beneath apple, black hawthorn, and ornamental hawthorn trees that were known to be infested in 2006 will be collected, taken to the laboratory, and the pupae extracted from them, with the goal of using flies that emerge from them within a few weeks of collection. Pupae will be shipped to Cornell University in Geneva, New York for testing in a flight tunnel by Dr. Charles Linn (objective 3). In addition, in summer/fall 2007, collections of higher numbers of pupae will also be made for anticipated further testing. Large numbers of apple, black and ornamental hawthorn fruit will be collected from trees and laid on hardware cloth or in tubs. Several times each week, pupae will be collected and stored in moist soil. After one to two weeks at ambient conditions, pupae will be stored at 38-40 ºF for 6 months. These pupae will also be sent to New York for testing (objective 3). Objective 2. At field sites in central and western Washington, black hawthorn, eastern red hawthorn, and apple lures will be tested along with a blank control. An ammonium carbonate (AC) lure will also be used for comparison. AC lures will be clear plastic vials containing 10 g AC. Lids have two 1-mm holes. Release rates from three or six lures of each fruit volatile and AC lure will be estimated by weighing lures on a balance at various times after exposure in a hood with temperatures of 60-73 ºF and RH of 30-50%, and with air flow of ~54 feet per min. One 3.5-inch diameter red sphere coated with sticky adhesive and baited with one lure will be used per test tree. The control will be a red sphere with no lure. Each test will include a control, at least one fruit volatile treatment, and an AC treatment. Test trees will be arranged in a randomized block design with four to six replications each. Each trap will be placed 4.5-6 feet above the ground on the south-facing side. Trap positions will be re-randomized within blocks once or twice a week, at which time all flies will be removed and counted. All traps will be removed and replaced with new ones after one month. Tests will begin in late June, July, or September and last at least 30 days. Objective 3. The behavioral responses of flies to fruit volatile collections and synthetic blends will be measured in a 72 inch long, 24 x 24 inch square flight tunnel. Sexually mature, odor naïve flies > 10 days old will be individually transferred to a screen cage, which will then be placed on a stand 1 m downwind from a 3 inch diameter red plastic sphere baited with a particular fruit blend. Flies are responsive if they display anemotactic flight over the 1 m distance to reach the source sphere. Documents Trust with WA State Commission on Pesticide Registration. log 32979.