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

Beginning in 1993, Florida's citrus has been invaded by citrus leafminer (Phyllocnistis citrella Stainton), brown citrus aphid (Toxoptera citricida Kirkaldy, and the Asian citrus psylla (Diaphorina citri Kuwayarna. The source(s) of these pests remain unknown but other Caribbean countries also suffered invasions. Brown citrus aphid and Asian citrus psylla are vectors of citrus tristeza virus and greening disease, respectively, while citrus leafminer damage provides openings for invasion of the canker pathogen into the foliage. All three were suitable candidates for classical biological control and Dr. Ru Nguyen (Division of Plant Industry, Gainesville, FL) and l collaborated on importing, evaluating, rearing and releasing parasitoids between 1993 and the present. Two parasitoids (Ageniaspis citricola and Cirrospilus quadristriatus) of the citrus leafminer were imported from Australia, Thailand and Taiwan. Both parasitoids established in Florida, and A. citricola has become dominant. 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, 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. Such information assisted the recipients in obtaining local release permits, thus reducing the costs of importation and release. Two parasitoids were imported for control of the Asian citrus psylla: Tamarixia radiata Waterston and Diaphorencyrtus aligarhensis (Shafee, Alam & Agarwal) through the kind assistance of colleagues in Taiwan. Again, we made both parasitoids available to countries in the Caribbean, along with rearing methods and our risk assessment data. Finally, the parasitoid Lipolexis scutellaris was imported from Guam for a classical biological control program directed against the brown citrus aphid. Classical biological control historically has had an ethos that fostered cooperation, interconnections, and sharing of resources and knowledge. This ethos must be maintained if classical biological control is to be sustained as a viable pest management tactic. We must share information and resources in order to win our struggle to manage invasive pests.