Attracticidal spheres for controlling apple maggot flies: commercial‐orchard trials

Abstract

AbstractWooden pesticide‐treated red spheres and biodegradable sugar/flour pesticide‐treated red spheres were compared with wooden sticky‐coated red spheres and insecticide sprays for controlling apple maggot flies, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), in small blocks of apple trees in Massachusetts commercial orchards in 1997, 1998 and 1999. Pesticide‐treated 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 24 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 were more durable 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.