1a. Objectives (from AD-416):
Develop pest management methods for paper wasps that are invasive on Tinian and other islands in the Marianas.
1b. Approach (from AD-416):
Chemical attractants and baits will be tested to determine efficacy against Tinian Island wasps. Pheromones will be identified to produce possible attractants. Optimized lures and traps will be evaluated as tools to reduce wasp populations. Documents reimbursable with Dept. of Navy/DOD. Log 40366. Formerly 5352-22000-017-56R (6/10); 5352-22000-019-22R (1/11).
3. Progress Report:
The work summarized in this progress report relates to objective number 3 in the Project Plan for 001-00D: 3. Discover and develop chemical attractants for codling moth, fruit flies, pear psylla, and other insect pests of temperate tree fruits and their natural enemies. This work relates to those objectives because of the depredations of invasive paper wasps on cherry fruits and grapes, and the stinging hazards of invasive social wasps for farm workers picking fruit. A series of field experiments on Tinian Island tested a variety of known wasp attractants and baits, and fermented sweet baits and fruit juices to determine if the pest Polistes stigma could be trapped with any of these materials. All of these experiments yielded negative results. Subsequent observation of Polistes stigma on Tinian Island showed a consistent feeding by the wasp at several species of flowers. Work on chemical attractants then shifted to consideration of possible wasp orientation to the volatile chemicals produced by these plants and flowers. Chemical samples of flower odors were obtained using a field-portable volatile collection system. The flower chemistry was then characterized for a Euphorbia species, Colubrina asiatica, and an Ipimorpha species, using combined gas chromatography and mass spectroscopy. Subsequent analysis using GC-EAD, combined gas chromatography/electroantennography, showed consistent responses by wasp antennae to several of the compounds from each of the three species of plant. Additional work is planned to test for wasp attraction to those compounds, using both a laboratory olfactometer assay, and field testing using traps. The makeup of the species of social or stinging wasps was determined for Tinian and Saipan of the Northern Marianas Islands, at four times over the life of the project. This was accomplished by the netting of large numbers of wasps on and about vegetation, and the collection and analysis of over 100 wasp nests. Polistes stigma was always dominant on Tinian Island, with small numbers of Ropalidia marginata. On Saipan, Ropalidia marginata appeared to be dominant, with fewer numbers of Polistes stigma present.