Question of the Week – Squash Beetle Trenching

This week, the question was: Why is a portion of this squash leaf discolored?

The light-colored tissue we see here is the result of squash beetle behavior known as “trenching.” Trenching cuts off (at least temporarily) the translocation of cucurbitacin defense compounds, to preserve the palatability and quality of the squash foliage feeding site. The beetles in this particular field were sprayed and killed after trenching this section of leaf so the yellow tissue remains and was not eaten. Similar behavior occurs with other insects, such as dogbane leaf beetles. Read more about squash beetles here.

This week’s question is from Extension Entomologist Tom Bilbo.

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