Area-Wide Integrated Control of Oriental Fruit Fly Bactrocera dorsalis and Guava Fruit Fly Bactrocera correcta in Thailand

Two tephritid species namely the oriental fruit fly Bactrocera dorsalis Hendel and the guava fruit fly Bactrocera correcta Bezzi are considered to be the key insect pests of fruit production in Thailand, causing yield loss and quality degradation. This leads to poor commercialization in domestic markets and quarantine restrictions from importing countries. A decade of effective cooperation between Thailand's Department of Agricultural Extension (DOAE), the International Atomic Energy Agency (IAEA), and the Food and Agriculture Organization of the United Nations (FAO) has resulted in the implementation of an area-wide integrated fruit fly management programme which includes a sterile insect technique (SIT) component. The programme consists of two distinctive pilot areas with associations of smallscale mango growers covering 70 square kilometres in the Ratchaburi (western) and Pichit (northern) Provinces. The ongoing programme is aimed at controlling B. dorsalis and B. correcta through monitoring, orchard sanitation, selective application of bait sprays, and the release of sterile flies. Both species are mass-reared and sterilized at a facility located in Pathumthani Province following standard operational procedures described in this paper. The average weekly production during the mango season is 20 million B. dorsalis and 10 million B. correcta. After sterilization the pupae are transported weekly to the pilot areas, reared to the adult stage and ground-released at fixed release sites. Quality of the released sterile flies is monitored through the use of a trapping network to measure their distribution and abundance, whilst the success of the control is monitored using periodic fruit sampling to assess the percentage infestation. The integrated approach has been effective in controlling fruit flies by reducing damage from over 80% before programme implementation to an average of less than 3.6% in Ratchaburi Province in the past five years (2000 to 2004). Meanwhile, in Pichit Province where the control programme has been carried out for only two years (2003 and 2004), the infestation has been reduced from 42.9 to 15.5%. This preharvest suppression, combined with postharvest risk mitigation measures, has opened the possibility for exports of mango produced in these selected pilot areas to some of the most stringent and lucrative markets such as Japan. An economic feasibility study conducted in 2002 clearly shows that fruit fly control in Thailand using an integrated area-wide approach with an SIT component could be expanded to other production areas with significant economic returns.

KEYWORDS mango, oriental fruit fly, Bactrocera dorsalis, guava fruit fly, Bactrocera correcta, suppression, sterile insect technique, male annihilation technique, mass-rearing, ground release, economic feasibility, grower organization, Thailand