Oxygenated Phosphine Fumigation for Control of <I>Epiphyas postvittana</I> (Lepidoptera: Tortricidae) Eggs on Lettuce

Abstract

Light brown apple moth, Epiphyas postvittana (Walker), is a quarantined pest in most countries. Its establishment in California and potential spread to other parts of the state and beyond make it urgent to develop effective postharvest treatments to control the pest on fresh commodities. Fumigation with cylindered phosphine at low temperature has emerged to be a practical methyl bromide alternative treatment for postharvest pest control on fresh commodities. However, its use to control E. postvittana eggs on sensitive commodities such as lettuce is problematic. E. postvittana eggs are tolerant of phosphine and long phosphine treatment also injures lettuce. In the current study, E. postvittana eggs were subjected to oxygenated phosphine fumigations to develop an effective treatment at a low storage temperature of 2 degrees C. In addition, soda lime as a CO2 absorbent was tested to determine its effects in reducing and preventing injuries to lettuce associated with phosphine fumigations. Three-day fumigation with 1,000 ppm phosphine under 60% O2 achieved 100% mortality of E. postvittana eggs in small-scale laboratory tests. In the presence of the CO2 absorbent, a 3-d large-scale fumigation of lettuce with 1,700 ppm phosphine under 60% O2 resulted in a relative egg mortality of 99.96% without any negative effect on lettuce quality. The 3-d fumigation treatment without the CO2 absorbent, however, resulted in significant injuries to lettuce and consequential quality reductions. The study demonstrated that oxygenated phosphine fumigation has the potential to control E. postvittana eggs and the CO2 absorbent has the potential to prevent injuries and quality reductions of lettuce associated with long-term oxygenated phosphine fumigation.

Nitric oxide fumigation for postharvest pest control on lettuce

“…Methyl bromide fumigation is phytotoxic to lettuce . Low temperature fumigation with cylindered phosphine required 3 days to control N. ribisnigri on lettuce and the treatment also caused injuries to lettuce due to accumulation of CO 2 in fumigation chambers . Ethyl formate is not only phytotoxic to many fresh products but also has high absorption in fresh products .…”

“…Long treatment time like 3 days also caused injuries to lettuce due to accumulation of CO 2 from plant respiration . Oxygenated phosphine fumigation had higher efficacy than regular phosphine fumigation, but its commercial applications in the future are not clear. Thus, alternative safe and effective treatments are urgently needed to control postharvest pests on fresh products including lettuce.…”

Pest risk assessment of Amyelois transitella for the European Union

“…(2013) Liu et al. (2014) Grapholita molesta (Lepidoptera)Larvae2,157 ppm, in 95 h, two temperatures 5 and 8°C100%Shamilov (2012) Laphigma spp. Prodenia spp ./Geometridae (Lepidoptera)Larvae and adults500 ppm in 24 h at 4°C52.1–100%Finkelman et al.…”