noun
pine moth larva
Specifically refers to the larva of Dendrolimus spectabilis, a pest of pine trees.
マツケムシが松の葉を食べ尽くしてしまった。
The pine moth larvae ate up all the pine needles.
Compound of 松 (matsu, 'pine') + 毛虫 (kemushi, 'caterpillar'), literally 'pine caterpillar'.