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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #300010
Title: Oxygenated phosphine fumigation for control of Epiphyas postvittana (Lepidoptera: Tortricidae) eggs on lettuce

Author
item Liu, Samuel
item Liu, Yong Biao
item SIMMONS, GREGORY - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2014
Publication Date: 8/1/2014
Citation: Liu, S.S., Liu, Y.-B., Simmons, G.S. 2014. Oxygenated phosphine fumigation for control of Epiphyas postvittana (Lepidoptera: Tortricidae) eggs on lettuce. Journal of Economic Entomology. 107(4):1370-1376. https://doi.org/10.1603/EC13487.
DOI: https://doi.org/10.1603/EC13487

Interpretive Summary: Oxygenated phosphine fumigation is more effective than regular phosphine fumigation against light brown apple moth (LBAM), Epiphyas postvittana (Walker), eggs. However, the treatment can last for 3 days and such long fumigation treatment causes injuries and reduced quality to lettuce. In this study, we fumigated LBAM eggs with phosphine under 60% O2 at 2°C to develop a treatment that can be used to control LBAM eggs at storage low temperature. We also tested whether we could prevent lettuce injuries by including CO2 absorbent in phosphine fumigation. LBAM eggs were successfully controlled in 3 days with 1000 ppm phosphine in glass jars in laboratory fumigation tests. However, in large fumigation trials, the relative mortality of LBAM eggs reached 99.96% with 1700 ppm phosphine in fumigation chambers with lettuce. The presence of CO2 absorbent in oxygenated phosphine fumigations prevented lettuce injuries and helped retain lettuce quality. Fumigation in the absence of CO2 absorbent resulted in considerable injuries and quality reductions of lettuce. These findings are important in developing safe and effective low temperature oxygenated phosphine fumigation protocols for commercial postharvest pest control on lettuce or other sensitive fresh commodities.

Technical Abstract: Light brown apple moth, Epiphyas postvittana (Walker), has the potential to cause significant damage to California horticulture and agriculture due to the risk of becoming a pest and domestic and international quarantine of infested and at-risk commodities from infested areas. Postharvest treatment is urgently needed to control E. postvittana on potentially infested fresh commodities such as lettuce to safeguard their export and domestic distribution. Oxygenated phosphine is effective in controlling E. postvittana eggs. However, a long fumigation treatment is needed at low temperature and the treatment causes injuries to lettuce. In this study, E. postvittana eggs were subjected to oxygenated phosphine fumigations to develop an effective treatment at a low storage temperature of 2ºC, and CO2 absorbent was tested to determine its effects in reducing/preventing injuries to lettuce associated with phosphine fumigations. Three days fumigation with 1000 ppm phosphine under 60% oxygen controlled E. postvittana eggs effectively in small scale laboratory tests. In large scale fumigation tests in 442 liter fumigation chambers with lettuce, 3 d oxygenated fumigation with 1700 ppm phosphine resulted in a relative egg mortality of 99.96%. The presence of CO2 absorbent in 3 d oxygenated phosphine fumigation prevented injury and quality reduction of lettuce which occurred in phosphine fumigation without CO2 absorbent. These results have important implications for developing safe and effective low temperature phosphine fumigation protocols for controlling E. postvittana on lettuce and other fresh commodities.