also: むしコブ
noun
gall; cecidium
A plant growth caused by insects, mites, or other organisms. The term is technical but also used in nature guides. Synonymous with 虫癭 (ちゅうえい).
See also: 虫癭
この葉っぱに虫こぶができている。
A gall has formed on this leaf.
虫こぶの中には幼虫がいることが多い。
There is often a larva inside a gall.
Synonymous, but 虫癭 is more formal and used in scientific contexts. 虫こぶ is the common term.
Compound of 虫 (mushi, 'insect') and 瘤 (kobu, 'lump, bump'), literally 'insect bump'. The reading こぶ is the kun'yomi of 瘤.