Cucumber and tomato volatiles: influence on attraction in the melon fly Zeugodacus curcubitae (Diptera: Tephritidae)

Authors: NJUNGUNA, PETER - International Centre Of Insect Physiology And Ecology; MURUNGI, LUCY - Jomo Kenyatta University; FOMBONG, AYUKA - International Centre Of Insect Physiology And Ecology; Teal, Peter; Beck, John; TORTO, BALDWYN - International Centre Of Insect Physiology And Ecology

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2018
Publication Date: 7/25/2018
Citation: Njunguna, P.K., Murungi, L.K., Fombong, A., Teal, P.E., Beck, J.J., Torto, B. 2018. Cucumber and tomato volatiles: influence on attraction in the melon fly Zeugodacus curcubitae (Diptera: Tephritidae). Journal of Agricultural and Food Chemistry. 66:8504-8513. https://doi.org/10.1021/acs.jafc.8b03452.
DOI: https://doi.org/10.1021/acs.jafc.8b03452

Interpretive Summary: Fruit flies are an important insect pest with serious economic and crop impact. The melon fly is a type of fruit fly that causes damage to a wide range of agriculture plants, but prefers Cucurbitaceae (gourde family including melons). In eastern Africa, the melon fly has recently also become a major pest of tomato. Insect pests are often attracted to odors emitted by the plants they feed on or deposit eggs onto. To determine if the odors of cucumber and tomato were attractive to the melon fly, researchers from ICIPE, Nairobi, Kenya, in collaboration with researchers from the USDA-ARS Chemistry Research Unit in Gainesville, FL collected the odors of these two different host plants and subjected them to various tests using the melon fly. The researchers determined that 13 chemical odors were common to both cucumber and tomato. Of these 13 odors, seven odors, when mixed together, were able to attract both male and female melon flies in laboratory-based tests. The use of plant-based odors to attract insect pests can be an environmentally safe alternative for control of insect pests. Additionally, the ability to attract fruit flies that are not yet in the continental U.S. can help researchers and growers monitor U.S. crops for non-native insect pests.

Technical Abstract: The main hosts of the melon fly Zeugodacus curcubitae are cultivated and wild cucurbitaceous plants. In eastern Africa, the melon fly is a major pest of the Solanaceae plant Solanum lycopersicum (tomato). We hypothesized that shared species-specific volatiles may play a role in host attraction. We tested this hypothesis by comparing the olfactory responses of the melon fly to Cucumis sativus (cucumber) (Cucurbitaceae) and tomato plant odors in behavioral and electrophysiological assays, followed by chemical analysis to identify the key compounds mediating the interactions. Our results identified 13 shared components between cucumber and tomato plant odors. A synthetic blend of seven of the shared components dominated by monoterpenes at concentrations mimicking the volatile bouquet of cucumber and tomato, attracted both sexes of the melon fly. Our results suggest that presence and quantity of specific compounds in host odors are the main predictors for host recognition in Z. curcubitae.