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T-STAR, Tropical & Subtropical Agric. Research
Biological Control of the Two-spotted Leafhopper
Dr. Jian Duan and Dr. Russell Messing, Department of Entomology, University of Hawaii, Kauai Agricultural Research Center, 7370-A Kuamoo Road, Kapaa, HI  96746


The two-spotted leafhopper, Sophonia rufofascia, originally described in southern China, was first discovered in Hawaii in 1987, and has since spread to all major Hawaiian islands. This insect is extremelyTwo-spotted leafhoppers mating polyphagous, attacking over 300 species of host plants in 83 families (Fukada 1996). Among the host plants, 68% are economically important fruit, vegetable, and ornamental crops; 22% are endemic to the Hawaiian islands (including 14 rare and endangered species); and 10% are exotic weeds. Many economically important crops attacked in Hawaii are also grown in other areas of the Pacific and Caribbean basins. The recent discovery of resident breeding populations of the two-spotted leafhopper in ornamental, vegetable, and fruit crops in California adds urgency to the need for biological control measures to curtail the spread of this insect. The photo above shows two S. rufofascia mating (back to back).

The goal of our research is to initiate a classical biological control program against this invasive leafhopper. This program focuses on exploration for and identification of undescribed or previously described but unexploited natural enemies (parasitoids) from southern China, the most probable native home of the leafhopper. We will also conduct introduction, quarantine, and host testing of promising parasitoids, as well as laboratory studies to ascertain the environmental compatibility and efficacy of the parasitoids in suppressing leafhopper populations.

During the past 8 months (July 1, 1998 - March 1, 1999), we studied the bionomics and rearing feasibility of Sophonia rufofascia leafhoppers in Hawaii. Sophonia rufofascia was successfully reared on green ti and guava plants for 2 generations. Adult S. rufofascia becomes reproductively mature 10 - 14 days after emerging ; each female lays 1 - 2 eggs per day. The egg takes about 4 weeks to hatch; and nymphs take 7 - 8 weeks to develop to adults. These baseline data form a solid foundation for further work on parasitoid exploration, rearing, and quarantine testing. Also, the long developmental time of leafhopper eggs suggest that egg parasitoids (e.g., Chaetomyma sp) may be effective in controlling the leafhopper populations because of the potentially long parasitoid exposure windows. The development of procedures for rearing the host, Sophonia rufofascia, is the first step to successfully rearing parasitoids imported from China.

Currently, one species of egg parasitoid (Chaetomyma sp) has been collected from eggs of a Sophonia leafhopper ( Sophonia furnalinca) in South China (Guanzhou province). After the exact species identity is confirmed, we will import the collected parasitoid to the quarantine laboratory of the Hawaii Department of Agriculture, and conduct tests there for its efficacy in parasitizing S. rufofascia. We hope that by the end of the project, we will have successfully introduced an effective egg parasitoid into Hawaii for control of Sophonia rufofascia.

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