Plant essential oils as biopesticides for Caribbean fruit fly, Anastrepha Suspensa

Authors: Yang, Xiangbing; Tabanca, Nurhayat; Cloonan, Kevin; Kendra, Paul

Submitted to: International Symposium on Fruit Flies of Economic Importance
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/2022
Publication Date: 11/29/2022
Citation: Yang, X., Tabanca, N., Cloonan, K.R., Kendra, P.E. 2022. Plant essential oils as biopesticides for Caribbean fruit fly, Anastrepha Suspensa. International Symposium on Fruit Flies of Economic Importance. Sydney, Australia. 13 – 18 Nov 2022.

Interpretive Summary:

Technical Abstract: The Caribbean fruit fly, Anastrepha suspensa (Loew), is a pest of over 100 fruit crops, including guava and citrus grown commercially in Florida, USA. Management of tephritid fruit flies often relies on bait sprays that incorporate synthetic insecticides. However, extensive use of these conventional insecticides has led to development of pesticide resistance in target species, contamination of the environment, and harmful effects on non-target organisms. Many plant extracted essential oils (EOs) have demonstrated toxic effects against insect pests, and therefore show promise as environmentally friendly alternatives to conventional insecticides. In this study, 18 EOs (representing six plant families: Apiaceae, Asteraceae, Cupressaceae, Lamiaceae, Myrtaceae, and Zygophyllaceae) were evaluated for toxicity against adult female A. suspensa to determine their potential as biopesticides. GC-MS was used to analyse, isolate, and quantify the volatile chemical components collected from the plant EOs. Toxicity of each EO was determined using a topical bioassay. Aliquots of 1µg EO at different concentrations were applied to the dorsal thorax of adult females using a micro-applicator. Acetone was used as a control and all treated flies were kept overnight before scoring mortality results for data analysis. Of the18 EOs tested, 13 were effective toxicants against A. suspensa females, with varied median lethal dosage levels. In particular, the EOs from chamomile and juniper showed strong toxicities against A. suspensa. EO from Chinese chamomile showed stronger toxicity (LD50: 7.58µg/fly) than EO from German chamomile (LD50: 9.30µg/fly), and juniper EO extracted from fruit exhibited greater toxicity than EO extracted from leaves (10.45 and 22.07 µg/fly, respectively). Analysis of juniper oils indicated that a- and ß-thujone were the most abundant components, and their toxicity in topical bioassays was similar to that observed with whole juniper oils. EOs extracted from chamomile and juniper demonstrated the best potential as alternatives to conventional pesticides for control of A. suspensa. With juniper EOs, the a- and ß-thujone constituents appeared to play a significant role in contributing to the toxicity of A. suspensa. Although more research is needed, this study provides useful information on the application of plant EOs for development of alternative management strategies for the Caribbean fruit fly.