Field release and evaluation of the parasitic wasp Tamarixia radiata (Hymenoptera: Eulophidae) against Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae) in Florida

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is an efficient vector of the bacterium Candidatus Liberibacter asiaticus, causal organism of the Asian form of huanglongbing (HLB) also known as citrus greening disease. ACP and HLB, identified from Florida in 1998 and 2005, respectively, pose a serious threat to citrus industry. Biological control has been effective in controlling ACP in the islands of Reunion, Guadaloup and Puerto Rico. Tamarixia radiata, a species specific ectoparasitoid of D. citri was imported from Taiwan and South Vietnam and released in Florida in 1999. Our studies during 2006-2007 showed that the parasitoid was established throughout the citrus growing region of the state, although parasitism rates were variable, averaging <20% during spring and summer and increasing to 39% in September and 56% in November in the central and southwest regions. We initiated a mass rearing program using the already established strain and brought in new colonies from Pakistan, South China and North Vietnam. More than 250,000 adults of T. radiata from all 4 colonies were released during 2009-2011. We have observed parasitism rates of up to 60% at release sites during spring and summer compared to < 20% at sites with no releases, showing that augmentative release can potentially increase incidence of parasitism by T . radiata in the field. Cooperative efforts with citrus producer OrangeCo, the Division of Plant Industry (DPI), and USDA-ARS are aimed at establishing large scale mass rearing and release facilities to increase ACP mortality and reduce the incidence of HLB, particularly during spring when young shoots and psyllids are abundant.