Submitted to: Entomologica Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2000
Publication Date: 8/15/2000
Citation: PROKOPY, R.J., WRIGHT, S.E., BLACK, J.L., HU, X.P., MCGUIRE, M.R. ATTRACTICIDAL SPHERES FOR CONTROLLING APPLE MAGGOT FLIES: COMMERCIAL-ORCHARD TRIALS. ENTOMOLOGICA EXPERIMENTALIS ET APPLICATA. 2000. v. 97. p. 293-299.
Interpretive Summary: The apple maggot is an insect that can cause millions of dollars of damage to apples in the eastern and northeastern U.S. if left uncontrolled. Currently, control is accomplished by the application of chemical insecticides via sprayers. Public concerns over misuse of pesticides has led to the Food Quality and Protection Act which will affect the number of pesticides available for use on fruit and the number of applications allowable to control insect pests. A new strategy is to deploy starch-based, biodegradable spheres that attract and kill adult apple maggot flies before they lay eggs. The spheres are deployed only around the edge of the apple orchard and contain very small amounts of pesticide. Thus, no pesticide comes in contact with the fruit. We found that fruit damage was not different between plots treated with standard chemical insecticides and plots protected by the new spheres. This information will be of use to scientists involved in fruit fly research and by fruit producers and consumers.
Technical Abstract: Wooden pesticide-treated red spheres and biodegradable sugar/flour pesticide-treated red spheres were compared with sticky-coated red spheres and insecticide sprays for controlling apple maggot flies, Rhagoletis pomonella (Walsh), in small blocks of apple trees in Massachusetts' commercial orchards in 1997, 1998, and 1999. Wooden and sugar/flour spheres received a coating of 70% latex paint, 20% feeding stimulant (sucrose), and 10% formulated insecticide (containing 20% imidacloprid). To replenish sucrose lost during rainfall, wooden spheres were capped with a disc comprised of hardened sucrose that seeped onto the sphere surface, whereas the surface of sugar/flour spheres received sucrose that seeped from the interior. Each year, each of the 26 perimeter trees of each non-sprayed block received a sphere baited with butyl hexanoate (an attractive component of host fruit odor) with the intent of intercepting immigrating flies. Based on captures of flies on unbaited sticky-coated red spheres placed near the center of each block and on periodic samples of fruit for injury, there was a consistent pattern of treatment performance. Each year, sticky-coated spheres were only slightly less effective than two or three sprays of organophosphate insecticide, sugar/ flour pesticide-treated spheres were only slightly less effective than sticky spheres, and wooden pesticide-treated spheres were least effective. Versions of pesticide-treated spheres used in 1999 performed better than those used in previous years, but further improvement is needed before either wooden or sugar/flour pesticide-treated spheres can be recommended for grower use.