The Biology and Behaviour of the European Pine Shoot Moth Rhyacionia buoliana (Schiff.), in Southern Ontario II. Egg, Larva, and Pupa

Abstract

AbstractThis is the second of two papers on this subject. The eggs of R. buoliana are usually found singly or in small groups on the hark or needle sheaths of new shoots, except under conditions of severe infestation where new foliage is in short supply. The first two instars feed on needles from within webs. Third-instar larvae mine one or more buds and cease feeding in late summer before the advent of unfavourable temperatures. Low temperature, lethal to overwintering third-instar larvae, is one of the most important and readily measured mortality factors, Larvae spin webs and moult before they resume feeding in April or May. Migration, usually upward in the tree crown, and web construction continue throughout the spring feeding period. Larvae within two feet of the ground surface on trees less than eight feet tall complete their development earlier than larvae at higher levels. Parasitism, based on previous extensive surveys, has very likely been underestimated.