Which pest is identified by fine silken webbing around new needles and where the growth turns brown as larvae are present in the webbing?

Which pest is identified by fine silken webbing around new needles and where the growth turns brown as larvae are present in the webbing?

• A. Pine needle sheath miner
• B. Spruce spider mite
• C. Douglas fir tussock moth
• D. Pine engraver beetle

Answer: (A)

Pine needle sheath miner is the pest that fits this symptom pattern. The larvae mine inside the needles and produce fine silken webbing around the new growth, and as they feed the needles and new growth turn brown. This combination of webbing around fresh needles plus browning from inside the needles is a hallmark of this species. The other pests show different signs: mites cause stippling and general bronzing with webbing but not typically silk tubes around new needles with larvae inside; tussock moths cause noticeable defoliation from larger caterpillars; and bark beetles attack under the bark, not on the needles with silk.

Pine needle sheath miner is the pest that fits this symptom pattern. The larvae mine inside the needles and produce fine silken webbing around the new growth, and as they feed the needles and new growth turn brown. This combination of webbing around fresh needles plus browning from inside the needles is a hallmark of this species. The other pests show different signs: mites cause stippling and general bronzing with webbing but not typically silk tubes around new needles with larvae inside; tussock moths cause noticeable defoliation from larger caterpillars; and bark beetles attack under the bark, not on the needles with silk.