Invertebrates
Squash Bug
Anasa tristis · also called squash bugs
A gardener flips over a squash leaf and finds a tidy cluster of bronze eggs glinting in the sunlight, a small discovery that, left unchecked, could mean an entire vine wilting to nothing within a matter of days.
Overview
The squash bug, Anasa tristis, is a common garden pest true bug found in grassland and garden habitat across most of North America wherever squash, pumpkin, and related plants grow. Its rapid, disease-spreading feeding damage, distinctive bronze egg clusters, and foul defensive odour make it one of the more genuinely troublesome insects a home vegetable gardener is likely to encounter.
A small bug with an outsized impact
It takes surprisingly few squash bugs, feeding steadily and injecting disruptive saliva as they go, to turn a healthy, thriving vine into a wilted, dying one in a remarkably short span of time.
Status
Least Concern — widespread and abundant across suitable habitat throughout North America wherever squash and related cucurbit plants grow.
Squash Bug: common questions
How does the squash bug damage garden plants?
Both nymph and adult squash bugs feed by piercing plant tissue and injecting saliva that disrupts the plant's water transport, causing leaves and entire vines to wilt rapidly, a condition gardeners commonly refer to as squash bug wilt.
How can you spot squash bug eggs before they hatch?
A female squash bug lays tightly packed clusters of shiny, bronze or copper-coloured eggs on the undersides of leaves, a distinctive and easily recognisable early warning sign that lets gardeners remove eggs before they hatch into damaging nymphs.
Can the squash bug spread plant disease?
Yes, this species can transmit yellow vine disease between plants while feeding, adding a secondary threat to gardens beyond the direct wilting damage its feeding alone already causes.
What does a squash bug do when threatened?
Like several other true bugs, it releases an unpleasant defensive odour when crushed or handled, a chemical deterrent meant to discourage predators and curious gardeners alike from further disturbing it.