Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae) responses to plant-associated volatile organic compounds: A mini-review

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus and C. L. americanus, the causal agents of huanglongbing (HLB), the world's most serious citrus disease. There are no therapeutic treatments for HLB and chemical insecticides are the primary means of controlling ACP. Although insecticide applications reduce local ACP populations, HLB spread has continued unabated. Because of insecticides' inefficiency, cost, and associated regulatory issues, growers are looking for additional tools for ACP control. There has been a strong interest in identifying plant species and their associated volatile organic compounds (VOCs) that repel or attract ACP. Identification of effective behavioral modifiers is a necessary first step to developing highly efficient management tools for monitoring, repelling, and controlling ACP. While initial studies used olfactometry and analytical instruments, current investigations have grown in scope to include tools such genetic modification, RNAi, and olfactory binding proteins to provide a more comprehensive understanding of ACP olfactory perception and behavioral response to VOCs. Here we provide an overview of the plant species and their associated VOCs that have been implicated as ACP behavioral modifiers.