Location: Crop Improvement and Protection ResearchTitle: Oxygenated phosphine fumigation for postharvest control of light brown apple moth on lettuce) Author
|Liu, Yong Biao|
Submitted to: Entomological Society of America Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2013
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Postharvest treatment for light brown apple moth (LBAM), Epiphyas postvittana (Walker), is needed to safe guard domestic distribution and export of U.S. fresh fruits and vegetables including lettuce as the pest becomes established in California with risk of potential spread. Oxygenated phosphine fumigation is effective against LBAM including eggs. However, the long treatment of at least 3 d to control LBAM eggs also causes injuries to lettuce. We hypothesize that the injuries associated with phosphine fumigation were caused by accumulation of plant metabolites. In this study, the levels of CO2 and ethylene were monitored over 3 d at 2ºC in fumigation chambers with lettuce, and lettuce and LBAM eggs were subjected to 3 d oxygenated phosphine fumigation with and without CO2 absorbent to evaluate their impact on lettuce quality. When lettuce was hermetically sealed in fumigation chambers to simulate a 3 d fumigation, CO2 level in the chamber increased steadily over time and reached 3.36% at the end of 3 d storage. Ethylene level was undetectable. Phosphine fumigation in the absence of CO2 absorbent resulted in significantly higher proportion of lettuce with injuries in the form of brown stains. The presence of CO2 absorbent prevented such injuries. The relative mortality of LBAM eggs over 3 d at 2ºC was 99.96% with 1500 ppm phosphine and 60% oxygen. These results suggest that injuries to lettuce were mainly caused by CO2 and use of CO2 absorbent has potential to prevent injuries to lettuce in phosphine fumigation. These findings have important implications in development of safe and effective low temperature phosphine fumigation treatment for controlling of LBAM on lettuce and other fresh commodities.