Squash bugs are flat, dark gray-brown insects about 5/8 inch long with orange and brown stripes along the edges of the abdomen. They suck sap from squash, pumpkins and other cucurbits, leaving yellow spots that turn brown and making young plants wilt. The most effective way to get rid of them is to destroy the bronze egg clusters under leaves, hand-pick nymphs and adults into soapy water, trap them under boards overnight, and clear plant debris in fall.
Table of Contents
Squash Bug Pictures: Adults, Nymphs and Eggs
| Stage | What it looks like |
|---|---|
| Adult | About 5/8 inch, flat, dark gray to dark brown, orange-and-brown striped edges |
| Young nymph | Light green body with black head and legs; clusters together |
| Older nymph | Light gray to brownish-gray, black legs and antennae; five stages in all |
| Eggs | Oval, about 1/16 inch, yellowish to shiny bronze, in clusters of about 20 |
Eggs are usually laid on the undersides of leaves in the V where two veins meet, and sometimes on stems. They hatch in about 10 days.
Squash Bug Damage
- Yellow speckles on leaves that turn brown and crispy
- Wilting leaves or whole vines, even with moist soil
- Seedlings and young transplants dying
- Scarred or sunken spots on fruit late in the season
Winter squash, pumpkins, summer squash and zucchini suffer most; cucumbers and melons less often. Squash bugs can also spread cucurbit yellow vine disease in some regions.
Squash Bug Life Cycle
Adults spend winter in plant debris, woodpiles, under rocks and around buildings. They move to squash plants in late spring or early summer, mate and lay eggs. Nymphs hatch in about 10 days and mature in four to six weeks. There is usually one generation a year, with a partial second in warm summers.
How to Get Rid of Squash Bugs
1. Destroy the eggs
Check the undersides of leaves every two or three days from early summer. Crush egg clusters, scrape them into soapy water, or lift them off with duct tape.
2. Hand-pick nymphs and adults
Knock them into a bucket of soapy water in the morning, when they’re slow. A handheld vacuum works for large groups of nymphs.
3. Board traps
Lay boards, shingles or folded newspaper on the soil near plants in the evening. Squash bugs gather underneath overnight; collect and destroy them each morning.
4. Row covers
Cover young plants with floating row cover from planting until flowering, then remove it so bees can pollinate.
5. Trap crops and tolerant varieties
Blue Hubbard squash planted around the edge draws squash bugs away from your main crop. Butternut, buttercup and some pumpkin varieties tolerate feeding better than zucchini and yellow squash.
6. Insecticides, timed right
Sprays work best on young nymphs; adults are hard to kill. Insecticidal soap, neem oil or spinosad can control small nymphs when sprayed directly on them, on the undersides of leaves. The University of Minnesota suggests treating when you find about one egg mass per plant. Spray late in the day to protect bees during flowering, and follow the label.
7. Fall cleanup
Remove vines, fruit and debris after harvest, avoid straw mulch near squash, and keep garden edges mowed so adults have fewer places to spend winter.
Squash Bugs in the House
Adults sometimes wander indoors in fall looking for shelter. They don’t breed, bite or damage anything inside. Vacuum them up and seal gaps around windows and doors.
Squash Bug vs Stink Bug
Squash bugs are longer and narrower than stink bugs, with a flatter back and less of a shield shape. Stink bugs are broader, often with banded antennae, and feed on many plants rather than mainly cucurbits. See stink bug pictures.
Squash bug control supplies
- Floating row cover to protect young plants
- Neem oil for young nymphs
- Insecticidal soap for nymph clusters
- Spinosad spray organic option for nymphs
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FAQs
A squash bug is a flat, dark gray-brown insect about 5/8 inch long with orange and brown stripes along the edges of its abdomen. Nymphs are light green to gray with black legs.
Dropping squash bugs into soapy water kills them quickly. Insecticidal soap sprayed directly on nymphs also kills them on contact, but adults are much harder to kill with sprays.
Squash bug eggs are oval, about 1/16 inch, yellowish to shiny bronze, and laid in clusters of about 20 on the undersides of leaves, often where two veins meet.
No. Squash bugs feed on plant sap and don’t bite people or pets.
Use row covers until flowering, check for eggs every few days, plant tolerant varieties or a Blue Hubbard trap crop, and clear plant debris in fall.
Sources
Facts in this guide are checked against the sources above and reviewed when they change. See how we research in our editorial policy.