Cocooning Behaviour of Overwintering Codling Moth Larvae

Abstract

Codling moth larvae seeking overwintering sites usually spin up during hours of darkness on the trunks and larger branches of apple trees rather than in the soil or in debris under the trees. The number on the ground depends on the suitability for cocooning sites of the bark on the tree and on the amount and type of debris on the ground. Gould and Geissler (1941) found that larvae did not spin up in bare and compact soil and Steiner (1929) observed that most larvae returned to the tree to spin cocoons when there was little or no litter beneath the trees. Baker (1944) reported eight to nine per cent spun up on the ground beneath unscraped trees, and 18 per cent where the loose bark scales were removed. Others (Headlee (1929). Worthley (1932), Gnadinger et al. (1940), Woodside (1941), and Stultz (1946), found that under natural conditions from 0 to 14 per cent spun up in the soil, in the cover crop, or in the debris on the ground.