Postharvest control of lightbrown apple moth using ethanol

The use of "Generally Recognized As Safe" (GRAS) compounds may provide an environmentally sustainable postharvest disinfestation method against key quarantine insect pests. GRAS compounds include ethanol when used in accordance with good manufacturing practice. We have determined the mortality responses of fifth instar lightbrown apple moth larvae (LBAM; Epiphyas postvittana) (Walker), on and off apples, to ethanol immersion and vapour treatments. Preliminary experiments showed that 99% (LC99) mortality can be achieved off-fruit with a 2-4 s immersion in 74.7% (v/v) ethanol. Immersion of LBAM on apples in 15%, 30% and 50% ethanol resulted in 10%, 59% and 91% insect mortality respectively. Different immersion times (up to 600 s) did not discernibly affect LBAM mortality on apples. Ethanol treatment resulted in LBAM mortality within 1 h of terminating immersion, and there was a slight trend for insect mortality to increase when the assessment period was extended to 48 h (insects off fruit) or 120 h (insects on fruit). Insects immersed on-fruit showed a significantly higher level of mortality than those treated off-fruit. Preliminary experiments indicated that exposing LBAM on huh in open containers for 48 h to ethanol vapour provided by 20% and 50% ethanol solutions resulted in 97% to 100% mortality respectively. Ethanol treatments are a potentially useful disinfestation method.