Suppression of the Mediterranean Fruit Fly in Semi-Temperate Areas of Western Australia: A Review of Over 30 Years of Area Wide Management Practice

Abstract

The Mediterranean fruit fly (Medfly, Ceratitis capitata Wiedemann) is established in Western Australia, where it attacks a range of cultivated fruits and vegetables. In a long-term study, the number of male and female flies was recorded in towns and surrounding orchards in Manjimup (1991–2022) and Pemberton (1996–2022). Implementation of whole orchard integrated pest management (IPM) strategies included the use of insecticide treatments based on action thresholds. The application of early season insecticide + protein spot bait treatments eliminated the need for pesticide cover sprays. Synchronisation of treatment times within the same week or fortnight across all orchards in each district improved Medfly control within an area-wide management (AWM) program. From the initial 1992 baseline of 12.04 flies/trap/day (FTD) in Manjimup town and 0.42 FTD in commercial orchards, numbers were reduced 4-fold in the town (2.82 FTD) and 18.5-fold (0.0230 FTD) in the orchards. In Pemberton town, the Medfly population was very low (< 0.01 FTD) while in the surrounding orchards, high-density trapping detected only 29 adult Medfly over 27 years, with several years of zero numbers. A major contribution to the success of AWM in the two towns and surrounding orchards was the continuing awareness programs on Medfly control funded by industry, government, and town councils. These findings are valuable for designing AWM strategies for Medfly where growers and townspeople are motivated to cultivate pest-free produce for domestic consumption and market access.