Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2003
Publication Date: 6/10/2004
Citation: Neven, L.G. 2004. Effects of low temperature on egg and larval stages of the lesser appleworm (Lepidoptera:Totricidae). Journal of Economic Entomology. 97:820-823 Interpretive Summary: Lesser appleworm is a pest of commercially grown apples and pears in North America. It is desirable to develop non-chemical control measures against this pest in harvested fruits. Tests at the USDA-ARS Yakima Agricultural Research Laboratory, Wapato, WA, were designed to determine which stage of this pest is most tolerant to cold treatments. It was found that the blackhead stage of the egg was the most cold tolerant egg stage, requiring approximately 25 days of cold storage at 2 degrees C to achieve 90% mortality. It was also determined that the last or fourth larval instar was the most cold tolerant stage of the lesser appleworm, requiring 71.5 days of cold storage at 2 degrees C to achieve 90% mortality. These results indicate that lesser appleworm is slightly more cold tolerant than the traditional apple quarantine pest, codling moth. This research is important in establishing information on the most cold tolerant internal feeding pest against which non-chemical quarantine treatments can be developed.
Technical Abstract: Lesser appleworm, Grapholita prunivora (Walsh), eggs were subjected to cold storage conditions, 2.0 degrees C +/- 0.2 degrees C for 0 to 90 days. The most tolerant embryonic stage was the blackhead stage (96-120-hour old eggs) with an LT90 of 25 days. The four larval instars of lesser appleworm were subjected to cold storage conditions, 2.0 degrees C +/- 0.2 degrees C for 0 to 280 days. The fourth instar was the most tolerant to cold storage with an LT90 of 71.5 days. Exposure to low temperatures such as those commonly used for fruit storage shows promise as an alternative to fumigation for lesser appleworm eggs and larvae on apples and pears after harvest.