Biocontrol program targets Asian citrus psyllid in California’s urban areas

wayama (Hemiptera: Liviidae), has emerged as the most important exotic insect pest of citrus in California. Damage is two-fold. First, psyllids cause direct injury to citrus through feeding on phloem juice in immature foliage, deforming the leaves (Halbert and Manjunath 2004); and second, and more importantly, they vector the bacterium Candidatus Liberibacter asiaticus (CLas), which causes the lethal and untreatable citrus disease, huanglongbing (HLB), also called citrus greening disease. Characteristic symptoms associated with CLas infection are reduced vigor, foliar discoloration and dieback, misshapen fruit with bitter juice and malformed seeds, premature fruit drop, overall yield reductions and, ultimately, tree death (Gottwald 2010). Though symptoms may not appear for several years, CLasinfected plants are bacteria reservoirs from which ACP acquires and spreads the HLB-causing pathogen. CLas spread is exacerbated prior to detection if ACP populations are high and not managed. While there are some differences in susceptibility across citrus varieties, virtually all commercially available varieties are vulnerable to CLas infection. HLB is the most important vector-borne disease threat to the citrus industry in the United States. ACP and CLas were first found in the United States in Florida in 1998 and 2005, respectively (GraftonCardwell et al. 2013). Since then, the ACP-CLas pathosystem has been detected in six U.S. states, and ACP establishment has been confirmed in 10 U.S. states. The emergence of HLB in Florida citrus orchards has had significant economic impacts. Approximately 75% of all citrus trees grown in Florida are infected with CLas. Consequently, production costs have increased by 33% because of increased ACP-CLas management, and productive acreage has declined by 44% (from a high of 815,100 acres in REVIEW ARTICLE