Euwallacea fornicatus Eichhoff (Coleoptera: Curculionidae: Scolytinae) is an ambrosia beetle native to Asia and a widespread pest of tea, Camellia sinensis (L.) Kuntze. In recent years, beetles morphologically identical to E. fornicatus (a cryptic species complex referred to as E. near fornicatus) have become established in the USA (Florida and California), Israel, Mexico and other countries. These invasive beetles are highly polyphagous and vector fungal pathogens that cause Fusarium dieback, a vascular disease of avocado (Persea americana Mill.), woody ornamentals, and native forest trees. Previously, we identified piperitone (p-menth-1-en-3-one) as a new repellent for host-seeking E. nr. fornicatus in Florida. In this study, we compare efficacy of piperitone to two other repellents, verbenone and α-farnesene, all formulated in plastic bubble dispensers. Two replicate field tests were conducted in Florida avocado groves. Each test was run for 12 weeks and compared captures of beetles in baited traps (containing quercivorol and α-copaene lures) versus captures in traps containing lures plus repellent. To complement field tests, SuperQ collections followed by GC analyses were performed to document temporal patterns in emissions from repellent dispensers over a 12-week period. In addition, electroantennography (EAG) was used to quantify beetle olfactory response to each repellent. Overall, repellency was comparable with piperitone and verbenone, resulting in 50-70% decrease in beetle captures, with longevity of 10-12 weeks. No significant decrease was observed with α-farnesene. EAG responses to piperitone and verbenone were also equivalent, and significantly greater than response to α-farnesene. Since piperitone is much less expensive than verbenone, this study identifies an economical alternative repellent for incorporation into pest management programs for E. nr. fornicatus.

Evaluation of repellents for Euwallacea nr. fornicatus, a pest ambrosia beetle in Florida avocado groves

2019 Fall National Meeting

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