Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/1/2001
Publication Date: 11/1/2001
Citation: STELINSKI, L.L., LIBURD, O.E., WRIGHT, S., PROKOPY, R.J., BEHLE, R.W., MCGUIRE, M.R. COMPARISON OF NEONICOTINOID INSECTICIDES FOR USE WITH BIODEGRADABLE AND WOODEN SPHERES FOR CONTROL OF KEY RHAGOLTIS SPECIES (DIPTERA: TEPHRITIDAE). JOURNAL OF ECONOMIC ENTOMOLOGY. 2001. v. 94(5). 1142-1150. Interpretive Summary: Fruit growers in southwest Michigan have relied on broad-spectrum insecticide sprays to control fruit flies, such as the apple maggot and blueberry maggot, before they infest the fruit. A new control device, biodegradable spheres, is being developed to control fruit flies without spraying. Wooden and biodegradable spheres, which mimic fruit to specifically attract the flies, were tested in field studies to compare different insecticide coatings for effectiveness and durability. Spheres treated with imidacloprid killed more fruit flies than did spheres coated with thiomethosam when placed in apple and blueberry plantings. In blueberries, these spheres provided season-long control (4 weeks), but lost activity in apple orchards, which require 12 weeks of control. Laboratory experiments confirmed that biodegradable spheres began to lose activity after 9 weeks of field exposure. This work supports the development of biodegradable spheres by identifying imidacloprid as the most effective insecticide coating. Observations made during these experiments also identified topics for future research to improve this device. Successful development of these spheres will benefit growers and consumers by providing an alternative control measure (which leaves no insecticide residues on the fruit) to broad-spectrum sprays. Also, the environment benefits because 100 times less chemical insecticide is applied to the field and control is targeted at specific key pests.
Technical Abstract: Field-based studies and laboratory bioassays were conducted with apple maggot, Rhagoletis ponwnella (Walsh ), and blueberry maggot, Rhagoletis mendax Curran, flies to investigate the performance and duration of activity of insecticide-treated biodegradable and wooden spheres for control of Rhagoletis species. Four neonicotinoid insecticide treatments including imidacloprid, thiamethoxam, and thiocloprid at 2% (AI) were evaluated with biodegradable spheres. In 1999, significantly more apple maggot flies were found killed by imidacloprid-treated spheres compared with thiamethoxam-treated spheres during early and late season. In 2000, spheres treated with either of two formulations of imidacloprid killed significantly more apple maggot flies compared with thiamethoxam, thiocloprid, and untreated spheres. In blueberries, there were no significant differences between the numbers of blueberry maggot flies killed by both imidacloprid-treated or thiamethoxam-treated spheres in 1999. However, during the 2000 blueberry field season, both formulations of imidacloprid were significantly more effective in killing blueberry maggot flies compared with spheres treated with thiamethoxam, thiocloprid and untreated controls. Overall, spheres treated with thiocloprid were ineffective and did not kill significantly more apple maggot or blueberry maggot flies compared with the controls.