This project aimed to develop sustainable ways of controlling insect pests on citrus trees in Southeast Asia. The project used the techniques of integrated pest management (IPM) and concentrated on China, Malaysia, Thailand and Vietnam. The work also sought to refine existing IPM programs for citrus that are currently used in Australia. The main technology studied was the application of petroleum spray oils (PSOs).
This project clearly demonstrated that petroleum spray oil is an effective selective pesticide across all 12 experimental locations in China and Southeast Asia. This supported previous research findings that incorporation of PSOs into citrus IPM programs provides as effective or better control of most major citrus pests than control programs based on broad-spectrum synthetic pesticides. Populations of natural enemies are also better conserved in plots using oil-based IPM than other spray programs. Studies conducted for 2 years at four locations demonstrated that up to 10 applications of 0.5% narrow range, phyto-protected oil sprays per season did not cause visible phytotoxicity or have any effect on yield. It also produced more attractive looking fruit in three of the four locations.