Field evaluation of glutathione and glutamic acid as host marking pheromones for control of tephritid fruit flies in a mango orchard in Kenya

Authors: CHESETO, XAVIER - International Centre Of Insect Physiology And Ecology; KIRWA, HILLARY - International Centre Of Insect Physiology And Ecology; MOHAMED, SAMIRA - International Centre Of Insect Physiology And Ecology; EKESI, SUNDAY - International Centre Of Insect Physiology And Ecology; Beck, John; TORTO, BALDWYN - International Centre Of Insect Physiology And Ecology

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2022
Publication Date: 12/19/2022
Citation: Cheseto, X., Kirwa, H., Mohamed, S.A., Ekesi, S., Beck, J.J., Torto, B. 2022. Field evaluation of glutathione and glutamic acid as host marking pheromones for control of tephritid fruit flies in a mango orchard in Kenya. Pest Management Science. 97:1585-1592. https://doi.org/10.1002/ps.7331.
DOI: https://doi.org/10.1002/ps.7331

Interpretive Summary: Fruit flies are pests to many agricultural commodities world-wide and incur significant physical and economic damage to these crop products. Using results from previous studies of two fruit fly species and the chemicals produced when these flies lay eggs on fruit, a USDA-ARS scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL and collaborators at the International Centre for Insect Physiology and Ecology (icipe) in Nairobi, Kenya investigated the use of three compounds and their ability to decrease fruit fly infestation of mangos. In field studies in Kenya two of the three compounds tested reduced fruit fly infestations by up to 75% relative to control studies. The results of this study may have a large impact on fruit fly control by using natural compounds that inhibit fruit fly infestations.

Technical Abstract: BACKGROUND: Globally, Tephritid fruit flies are a major constraint to fruit production. In Africa, a plethora of native and alien invasive fruit fly species represent a key challenge to horticultural industry. In an effort to develop a safer management tool for these pests, in a previous study, we had identified the tripeptide glutathione (GSH) and amino acid glutamic acid (GA), as the host marking pheromones (HMP) of the African fruit fly species Ceratitis cosyra and C. rosa, respectively. Here, we report on the field evaluation of these compounds and compare their efficacies with the oxidized form of glutathione (GSSG) and two controls (spot spraying with food bait (SS) and water (W) in reducing fruit fly infestations in mango orchards at two different agroecological zone (high- and low-lands) in Kenya. RESULTS: Adult emergence was significantly influenced by the treatments. GSH and GA reduced C. cosyra and C. rosa infestation by ~70-75% relative to control (W), and this varied with the pheromone and fruit fly species. The adult emergence in pheromone treated plants compared favorably with the positive control- spot spraying of food bait (SS). On the other hand, none of the HMPs had any effect on reducing infestation by the invasive fruit fly species Bactrocera dorsalis. CONCLUSION: These findings confirm our previous laboratory results and support the prospect of potential use of HMPs in the management of African indigenous fruit fly species.