noun
leaf folder caterpillar; leaf-rolling caterpillar
Refers to caterpillars that roll or fold leaves to create shelters; often used for pests of various plants.
庭のバラにハマキムシがついて、葉が丸まっている。
Leaf folder caterpillars have infested the roses in the garden, and the leaves are curled up.
ハマキムシは葉を巻いて巣を作る。
Leaf folder caterpillars roll leaves to make nests.
Compound of 葉巻 (はまき, 'leaf roll') and 虫 (むし, 'insect'), describing the caterpillar's habit of rolling leaves.