Squash Bugs Pest Guide

Squash bugs are one of the few pests known to feed exclusively on a select handful of crops while seemingly uninterested in everything else in the garden. Squash bugs will predominantly infest larger and tougher winter squash varieties such as pumpkin, hubbard, and acorn rather than the softer skinned summer squash, though they’re not entirely immune.

Sometimes found on watermelon, cucumber, and cantaloupe, squash bugs have an appetite for only about 5 types of crops in the home garden. Squash bugs are sap-suckers just like aphids, spider mites, or mealybugs and can be easily identified apart from similar pests that feed on sugars and plant tissue.

Often mistaken for the notorious stink bug, squash bugs also are known to release a sickly odor when threatened or harmed and should not be removed by hand. Although a squash bug infestation may seem impossible to rid your garden of, they are still susceptible to castile and dish soap solutions like many pests.

How to Get Rid of Squash Bugs

  • Squash Bug Distribution: Most prominent in warmer, southern states
  • Squash Bug Host Plants: Pumpkin, squash, watermelon, cucumber, cantaloupe
  • Squash Bug Life Cycle: 6-8 weeks
  • Squash Bug Eggs Per Lifetime: ~400
  • Squash Bug Control: High pressure hose, dish soap solution, spinosad spray, pyrethrin
  • Squash Bug Predators: Beetles, tachinid fly, parasitic wasps, birds, chickens
  • Most Common Squash Bug in North America: Common Squash Bug (Anasa tristus)
Squash Bugs Anasa tristus
Common Squash Bug (Anasa tristus)

What Do Garden Squash Bugs Look Like?

Squash bugs are not difficult to identify by their elongated grayish-brown hardshell bodies that appear to have been pressed flat along with their six legs seemingly flattened at right angles.

Squash bugs are often mistaken for stink bugs but, to the trained eye, squash bugs are far more elongated and rounded than the jagged stink bug. Squash bugs are a swarming pest and, even if one is difficult to identify on its own, an entire swarm should be more than enough to positively identify a squash bug infestation.

As squash bugs mature from nymph to adult, their complexion changes throughout their 6-8 week lifespan yet will remain a consistent dusty brown tone. Squash bugs essentially share the same body shape and size as box elder bugs, except without any black and red markings.

Squash Bug Damage

Squash Bugs Damage
Squash bug infestation of cucurbits

While there are many swarming and sap-sucking insects found annually in the home garden, the squash bug is the only one that feeds exclusively on crops within Cucurbitaceae, namely pumpkin, squash, watermelon, cucumber, and cantaloupe.

Just like aphids and spider mites, squash bugs do not feed directly on foliage but, rather, pierce the skin so that they consume a plant’s vital tissue and sugars.

Affected plants will begin to show signs of yellow leaf spotting before an actual infestation were to swarm.

Squash bugs are notorious carriers for cucurbit yellow vine disease which is easily transmitted via saliva during feeding, almost immediately causing aggressive yellowing and vine collapse on both summer and winter squash.

What Do Squash Bugs Eat?

Squash bugs are exclusive to the Cucurbitaceae family in which they’re primarily found on winter squash, pumpkin, and watermelon while occasionally known to feed on cucumber and cantaloupe, though not as frequently as larger vining fruit.

Squash bugs are among one of the many garden sap-suckers that pierce through tough foliage to access and drain a host plant’s essential sugars, tissue, and nutrients.

While squash bugs are far too small to devour whole gourds and winter squash, squash bugs can still blemish their thick skin causing fruits to become visually unappealing and unsellable. Squash bugs are widely known to prefer the tougher and thicker winter squash cultivars rather than soft-skinned summer varieties such as zucchini or straightneck.

Squash Bug Eggs

Squash bug eggs are fairly easy to identify when compared to other sap-sucking pests such as aphids, mealybugs, spider mites, or thrips. They have a distinct red bronze appearance and are clean and elliptical, similar to chicken eggs.

Females lay about 20 eggs at a time in a tightly uniform mass on the underside of Cucurbits, usually winter squash, pumpkins, and watermelon.

Eggs hatch in 7-9 days, giving birth to hungry larvae that must feed aggressively for the next 30 days as they transition into a fully formed adult.

Compare the cleanliness and uniformity of squash bug eggs to the fibrous, messy, and haphazard manner that other sap-suckers will lay their eggs.

Squash Bug Eggs
Squash bug eggs on a cucurbit leaf

How To Get Rid of Squash Bugs

A squash bug infestation is daunting and can seem impossible to eradicate but, remember that they are only sap-suckers and can be removed using many of the same methods as other sap-suckers. Generally a high-pressure hose is more than enough to remove a swarming population but, for squash bugs, connect a solution sprayer to your nozzle to fill with dish or castile soap, creating a soapy and high-pressure solution.

Squash bugs are a little bigger and more tenacious than aphids or mites. It’s not advised to handpick or crush these insects from your crops because they are notorious for the noxious odor they produce when threatened or harmed.

Spinosad is a bacteria product created through fermentation known to help control squash bugs and can be purchased at nearly any nursery or garden supply store. Spinosad is generally featured as an active ingredient in insecticides, many of which are OMRI certified for organic use.

Squash Bug Treatment

How to Get Rid of Squash Bugs
Sprays and solutions for squash bug control

  • Bacillus thuringiensis (Bt) - Store bought spray consisiting of natural soil-borne bacteria
  • Spinosad Spray - Natural soil bacteria effective in treating several garden pests
  • Organic Neem Oil Spray - 1 tsp neem oil and 1/4 tsp dish soap to 1 quart water
  • Castile Soap - 1 tbsp to 1 quart water
  • Beauveria bassiana Spray - Natural fungi proven effective in treating many small garden pests
  • High Pressure Hose - Many insecticides are sold to be attached to any common garden hose for immediate control
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