Effects of Low Temperature on Egg and Larval Stages of the Lesser Appleworm (Lepidoptera: Tortricidae)

Abstract

Lesser appleworm, Grapholita prunivora (Walsh), eggs were subjected to cold storage conditions at 2.0 degrees C +/- 0.2 degrees C for 0-90 d. The most tolerant embryonic stage was the blackhead stage (96-120-h-old eggs) with an LT90 of 25 d. The four instars of lesser appleworm were subjected to cold storage conditions at 2.0 degrees C +/- 0.2 degrees C for 0-280 d. The fourth instar was the most tolerant to cold storage, with an LT90 of 71.5 d. 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.