Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/1998
Publication Date: N/A
Citation: Interpretive Summary: Attractive baits have been a primary component in management of fruit flies of major agricultural importance and there is a continuing need to identify chemicals that are attractive to these pest insects. Bacteria on plant surfaces, which may serve as a protein source for adult flies, may be strongly attractive to fruit flies. Enterobacter agglomerans is a bacterium that has been isolated from adult Caribbean fruit flies, as well as a number of other pest fruit flies. Therefore, scientists at the Center for Medical, Agricultural and Veterinary Entomology, ARS, USDA in Gainesville, Florida, in collaboration with scientists from the Department of Entomology, University of Massachusetts, Amherst, MA and Department of Entomology, University of Vermont in Burlington, VT, identified and quantified the primary chemicals released from E. agglomerans cultures. These chemicals were formulated in lures that release a constant amount of chemical at several concentrations. Attraction of Caribbean fruit flies was demonstrated in laboratory trials. Availability of these lures will allow testing of these microbial attractants for a variety of pest fruit flies and may provide a new tool for fruit fly monitoring and control.
Technical Abstract: Tests demonstrated that volatile chemicals emitted from Enterobacter agglomerans, a bacterium that has been isolated from adults as well as fruit infested with larvae of the Caribbean fruit fly, Anastrepha suspensa (Loew) and other pest fruit flies, are attractive to female A. suspensa in laboratory bioassays. 3-Methyl-1-butanol and ammonia were identified as the two primary volatile chemicals released from active cultures of E. agglomerans. No 3-methyl-1-butanol and little ammonia (16.0 ug/hr) is released from sterile tryptic soy agar plates. E. agglomerans - inoculated tryptic soy agar plates, however, released an average of 1.5 +- 0.53 ug/hr 3-methyl-1-butanol and 332.9 +- 239.16 ug/hr ammonia after 24 hr of growth. 3-methyl-1-butanol lures were formulated in a membrane-based system to provide a constant release rate of synthetic chemical. Release rates ranged from 0.046 +- 0.007 to 12.16 +- 2.76 ug/hr. In laboratory tests, equal numbers of females were captured in response to ammonium carbonate lures that released ammonia at the rate of 100 ug/hr and to 3-methyl-1- butanol lures that released 12.16 +- 2.756 ug/hr of synthetic material. The combination of the two lures was more attractive than ammonia alone. Availability of lures formulated for a range of 3-methyl-1-butanol release rates will facilitate field tests of this putative microbial attractant and may lead to a better understanding of the role of bacteria in the ecology of pest fruit flies.