Behavioral Assay on Asian Citrus Psyllid Attraction to Orange Jasmine

Abstract

The Asian citrus psyllid (ACP) is an important pest because it transmits a bacterium putatively responsible for huanglongbing, a devastating citrus disease. Research on ACP chemical ecology is of interest with respect to identifying attractants and repellents for managing the psyllid. We report on an assay for investigating ACP attraction to the foliar odor of one of its host plants, orange jasmine (Murraya exotica L.). Flush shoots from this plant were placed into 25 dram vials covered with a paper wrapper, a lid with a small entrance hole was snapped onto each vial, the vials were placed into a small cage, adult ACP were released into the cage, and the location of the adults was determined 24 h later. A positive response required an adult to find and enter a vial. When single males or females were released, they were attracted into vials with flush 64 % of the time. At release rates of 25, 50 or 100 adults with 30 repetitions for each rate, relatively large mean percentages of adults (ca. 83 %) positively responded to flush shoots. ACP can escape from the assay vial and will do so if flush is not present. Working with ACP in empty vials, fluoropolymer resin applied to the inside of vials reduced escapes but did not eliminate them. An entrapment funnel for reducing escapes was tested, but it reduced ACP response rates. A good method of preventing escapes remains to be developed. When two vials of flush were placed in the assay cage and one was treated with a candidate repellent, only 8 % of adults settled in the vial with the repellent.