Which pest defoliates 2-3 needle pines and has larvae in webbing around new growth with fine silken webs?

Which pest defoliates 2-3 needle pines and has larvae in webbing around new growth with fine silken webs?

• A. Pine needle sheath miner
• B. Bark beetles
• C. Douglas fir tussock moth
• D. Western spruce budworm

Answer: (A)

The key idea is that this pest uniquely matches both the host and the larval behavior described. Pine needle sheath miner targets pines that have 2 to 3 needles per fascicle, and its larvae feed inside or around the needle sheaths. They often produce fine silk and Webbing around the new growth as they feed, which is the exact description given. This combination—2-3 needle pines as hosts and larvae that live in silken webs around the new growth—points to the pine needle sheath miner. Bark beetles feed under the bark and leave galleries and pitch, not delicate silk webs on new growth. The Douglas-fir tussock moth and the western spruce budworm are caterpillars that prefer different hosts (Douglas-fir/true fir, and spruce/fir respectively) and show different kinds of feeding signs and webbing patterns, not the fine silken webs on 2-3 needle pines.

The key idea is that this pest uniquely matches both the host and the larval behavior described. Pine needle sheath miner targets pines that have 2 to 3 needles per fascicle, and its larvae feed inside or around the needle sheaths. They often produce fine silk and Webbing around the new growth as they feed, which is the exact description given. This combination—2-3 needle pines as hosts and larvae that live in silken webs around the new growth—points to the pine needle sheath miner.

Bark beetles feed under the bark and leave galleries and pitch, not delicate silk webs on new growth. The Douglas-fir tussock moth and the western spruce budworm are caterpillars that prefer different hosts (Douglas-fir/true fir, and spruce/fir respectively) and show different kinds of feeding signs and webbing patterns, not the fine silken webs on 2-3 needle pines.