|Massa, Michelle - UT-PANAM GRADUATE STUDENT|
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2008
Publication Date: June 25, 2008
Citation: Massa, M.J., Robacker, D.C., Patt, J.M. 2008. Identification of grape juice aroma volatiles and attractiveness to the Mexican fruit fly (Diptera: Tephritidae). Florida Entomologist. 91:266-276. Interpretive Summary: The Mexican fruit fly is a threat to citrus and other fruit industries because its larvae feed inside the fruit making it both undesirable to consumers and unexportable to many countries without disinfestation procedures. Although this pest occurs naturally only in North and Central America, regulatory agencies throughout the world maintain a constant vigil for its presence with monitoring traps. The most commonly used trap bait, yeast hydrolysate, is relatively ineffective and there is a general consensus that better baits and lures are needed. Preliminary tests in Mexico indicated that grape juice, a non-host of the fly, is more attractive than torula to native populations of the Mexican fruit fly. We identified the aroma components of grape juice and developed a synthetic mixture of the chemicals that is nearly equal to the juice in attractiveness to this fly. With further research, it may be possible to develop potent new grape aroma-based lures that can supplement or augment existing lures and toxic baits for control of fruit flies.
Technical Abstract: Volatiles from a Concord grape juice produced in Mexico were identified, tested for attractiveness and mixed into an attractant blend. Volatiles were sampled using solid phase microextraction (SPME). Chemicals were analyzed by gas chromatography and identified by mass spectrometry (GC-MS). Identified chemicals were ethanol, ethyl propionate, ethyl butyrate, ethyl 2-methylbutyrate, ethyl decanoate, ethyl dodecanoate, D-limonene, sorbic acid, benzoic acid, methyl anthranilate, and dimethyl antranilate. Chemicals were tested at two concentrations, 1 ug and 100 ng, for attractiveness to Mexican fruit flies (Anastrepha ludens) in laboratory cage-top bioassays. All test chemicals, except sorbic acid, were attractive to either sugar-fed or sugar-starved flies over both concentrations tested. A nine-component synthetic grape essence mixture was developed that matched the headspace volatiles profile of the grape juice. Attractiveness of the mixture was equal to that of the grape juice in laboratory bioassays. The mixture was 70% as attractive as the juice in traps in field tests. Results demonstrate that most of the attractive principals of the juice were identified.