Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2005
Publication Date: 12/20/2005
Citation: Liu, Y. 2005. Ultra-low oxygen treatment for postharvest control of nasonovia ribisnigri (homoptera: aphididae) on iceberg lettuce. Journal of Economic Entomology. 98:1899-1904. Interpretive Summary: Lettuce aphid, Nasonovia ribisnigri, is a common insect pest of lettuce in the U.S. and is quarantined on overseas market. Control of lettuce aphid on harvested lettuce is necessary for export of the U.S. lettuce to overseas markets such as Japan. This study focused on controlled atmosphere treatment with ultra-low oxygen (or ULO treatment) for postharvest control of lettuce aphid. In small-scale tests, both nymphs and alates of lettuce aphid were successfully controlled at oxygen level of 0.015-0.025% in 3, 2, and 1 day at 1, 5, and 10C respectively. In large-scale tests, ULO treatments, lettuce aphid was tested together with commercial iceberg lettuce. The insect was successfully controlled in 3 and 2 days at 3 and 6C respectively. At the end of ULO treatment, lettuce heads were stored at 2C for two weeks and postharvest quality of lettuce was then evaluated. None of insecticidal ULO treatment caused observable injury to lettuce. The results of this study suggest that ULO treatment has good potential for postharvest control of lettuce aphid on lettuce.
Technical Abstract: The lettuce aphid, Nasonovia ribisnigri, is a common pest of lettuce in the United States. Because it is quarantined in Japan, it hinders export of U.S. lettuce to the overseas market. Ultra-low oxygen treatments were studied for control of the insect on iceberg lettuce. Small-scale ultra-low oxygen treatments in plastic jars were conducted at 1, 5, and 10'C for different durations to determine effective treatment against nymphs and alates of N. ribisnigri. At oxygen levels of 0.015-0.025%, N. ribisnigri can be controlled in 3 days at 1'C, 2 days at 5'C, and 1 day at 10'C. Large-scale ultra-low oxygen treatments were conducted in bulk container treatment chambers with commercial iceberg lettuce heads for two days at 6'C with oxygen levels of 0.015% and 0.025% and for three days at 3'C with oxygen level of 0.015%. All treatments achieved complete control of N. ribisnigri. No negative impact on lettuce quality was detected after two weeks of post-treatment storage. Therefore, the selected treatment has potential as a commercially viable method.