The Sustainable Garden
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Stop Squash Bugs Naturally!
Keep Your Zucchini, Pumpkins & Squash Healthy Without Harsh Chemicals
Nothing is more frustrating than watching beautiful squash plants suddenly wilt in the middle of summer.
The culprit is often the squash bug—one of the most destructive pests of pumpkins, zucchini, and winter squash. The good news? With early detection and a few sustainable gardening practices, you can dramatically reduce damage while protecting pollinators and beneficial insects.
According to Utah State University Extension, squash bugs are the primary insect pest of cucurbits in Utah. Adults and nymphs feed by piercing stems and leaves and sucking out plant juices, causing wilting, yellowing, fruit damage, and even plant death.
🔍 Know Your Enemy
Adult Squash Bug
Squash bug adult
About 5/8 inch long
Gray-brown body
Flat-backed
Gives off an unpleasant odor when disturbed
Eggs
Squash bug egg mass
Shiny bronze or copper colored
Laid in clusters
Usually found on the underside of leaves
Nymphs
Squash bug nymphs
Hatch in about 10 days
Start bright red
Gradually turn gray as they mature
Easier to control than adults
🌿 Natural Ways to Control Squash Bugs
✅ Inspect Leaves Every Few Days
The single best control method is finding egg masses early.
✔ Turn leaves over
✔ Scrape eggs off with a fingernail
✔ Remove with duct tape
✔ Crush eggs
Checking every 2–3 days can dramatically reduce future populations.
✋ Hand Pick Adults & Nymphs
Early morning is the easiest time.
Drop insects into:
bucket of soapy water
rubbing alcohol solution
This works surprisingly well in home gardens.
🌱 Diatomaceous Earth
Sprinkle food-grade diatomaceous earth:
around the base of plants
on stems
where bugs crawl
The microscopic particles damage the insect's outer coating, causing dehydration.
Reapply after rain or overhead watering.
Avoid applying directly to flowers where pollinators are active.
🐝 Invite Nature's Helpers
Many beneficial insects help keep squash bug populations lower.
Beneficial insects include:
🪰 Tachinid Fly (Trichopoda pennipes)
Lays eggs on squash bugs
Larvae kill the pest naturally
🟡 Parasitic Wasps
Attack squash bug eggs
🐞 Lady Beetles
🕷️ Spiders
🪲 Ground Beetles
Planting nectar-rich flowers nearby helps support these beneficial insects throughout the season. Avoid broad-spectrum insecticides that kill both pests and beneficial insects.
🌼 Prevention is the Best Medicine
✔ Clean Up the Garden
After harvest:
Remove old vines
Remove fallen fruit
Dispose of plant debris
Adults spend winter hiding under garden debris.
✔ Rotate Crops
Don't plant squash in the same location every year.
Crop rotation helps interrupt the squash bug life cycle.
✔ Keep Plants Healthy
Healthy plants tolerate feeding much better.
Provide:
Consistent watering
Healthy soil
Compost
Mulch
Good fertility
✔ Use Floating Row Covers
Protect young plants early in the season.
Remove covers when flowering begins so pollinators can access blossoms.
🚫 Avoid These Common Mistakes
❌ Waiting until plants are wilting
❌ Ignoring egg clusters
❌ Spraying during bloom
❌ Depending on insecticides alone
Adult squash bugs are difficult to kill, so the most effective strategy is controlling eggs and young nymphs before populations explode.
🌱 Bloom Gardens Tip
A 5-minute garden walk every few days is often enough to prevent a major squash bug infestation.
The earlier you catch them, the easier they are to control—naturally.
Trouble viewing Bloom Gardens Magazine? Go to: https://bloomgardens.org/magazine/summer-2026/
Featured in this Issue:
*Woodstuff Landscape Supply
955 S 1950 W Springville Utah 84663
(801) 489-4777
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July Tips & Checklist
Start enjoying the tomato harvest.
Fertilize potatoes with nitrogen in early July.
Harvest summer squash and zucchini when they are still small and tender.
Deep water established trees and shrubs about once a month during the heat of summer.
Deadhead (cut off) spent blossoms of perennial and annual flowers.
Divide crowded iris or daylilies once they have finished blooming.
Visit alpine areas for wildflower displays.
Remove water sprouts (vertical shoots in the canopy) on fruit trees to discourage regrowth.
Renovate perennial strawberry beds by tearing out old crowns (mother plants) and applying fertilizer to stimulate new runners.
Remember that turfgrass only needs 1½ to 2 inches of irrigation per week. Learn about irrigation needs in your area.
Pests and Problems:
Check under leaves of pumpkins, melons, and squash plants for squash bugs.
Watch for mosaic virus in vine crops, such as cucumbers and watermelons, and remove infected plants to reduce spreading.
Watch for holes from tobacco budworm feeding in the leaves of petunias, nicotiana, geraniums, and other annual flowers.
Protect black locust trees (not honey locust) with a registered chemical to prevent locust borer damage.
Control codling moth in apples and pears to reduce wormy fruit. For specific timing see our Utah Pests Advisories.
Control walnut husk fly in walnuts, peaches, and apricots, typically on August 1st and 15th.
Learn how to identify a hobo spider.
Control European paper wasp with traps this time of year.
Monitor for damaging turfgrass insects.
The Sustainable Garden Newsletter is provided by Bloom Gardens
Happy Gardening!
Ramona
Bloom Gardens www.bloomgardens.org
