Classical biological control of citrus pests in Florida and the Caribbean: interconnections and sustainability.

Abstract

Beginning in 1993, Florida’s citrus industry has been invaded by citrus leafminer (Phyllocnistis citrella Stainton, Lepidoptera: Gracillariidae), brown citrus aphid (Toxoptera citricida Kirkaldy, Homoptera: Aphididae), and the Asian citrus psylla (Diaphorina citri Kuwayama, Homoptera: Psyllidae). The source(s) of these pests remain unknown but other countries in the Caribbean, as well as Central and South America, also have suffered invasions by these pests. Brown citrus aphid and Asian citrus psylla are vectors of serious citrus diseases (citrus tristeza virus and greening disease, respectively), while citrus leafminer damage provides openings for invasion of the citrus canker pathogen into the foliage. All three pests were considered suitable candidates for classical biological control. Dr. Ru Nguyen (Division of Plant Industry, Gainesville, Florida) and I have collaborated on importing, evaluating, rearing and releasing parasitoids for each pest into Florida’s 860,000 acres of citrus between 1993 and the present. Two parasitoids (Ageniaspis citricola Logvinovskaya, Hymenoptera: Encyrtidae and Cirrospilus quadristriatus, which was subsequently determined to be C. ingenuus Gahan, Hymenoptera: Eulophidae) of the citrus leafminer were imported from Australia, Thailand, and Taiwan with the assistance of several scientists. Both parasitoids have established in Florida, and A. citricola has become the dominant parasitoid while C. ingenuus has had no apparent effect. Ageniaspis citricola has been supplied to colleagues in the Bahamas, Bermuda, Brazil, Chile, Mexico, Honduras, and several other countries from our rearing program. In all cases, A. citricola was provided free of charge along with information on rearing methods, as well as the risk assessment that we developed prior to obtaining release permits from the Florida Department of Agriculture and Consumer Services and the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS). Such information assisted the recipients in obtaining local release permits, thus reducing the costs of importation and release for these agencies. Two other parasitoids were imported for control of the Asian citrus psylla: Tamarixia radiata Waterston (Hymenoptera: Eulophidae) and Diaphorencyrtus aligarhensis (Shafee, Alam and Agarwal) (Hymenoptera: Encyrtidae). The parasitoids were obtained through the kind assistance of colleagues in Taiwan. Again, we have made both parasitoids available to coun-