Squashing the Squash Bugs Dilemma

Sharon asks, “What can I do now to lessen the impact of squash bugs later? They are the one pest that I can almost always count on each year.”

The first thing to know is that squash bugs spend their winter as adults in protected, sheltered areas near, in, and around previously infested garden locations. So your first line of defense for the next season would be to thoroughly remove all garden debris, especially the debris of winter-type squash, which is the most common host of these pests.

Squash bug eggs on the underside of the squash leaves.

Late Spring / Early Summer….. Search and Destroy!


Your next course of action will come in late spring/early summer. Squash bugs become active and start to mate in June. The females lay clusters of eggs on the undersides of leaves and even stems of your new plants.

So, as soon as you transplant your squash plants outside, begin checking their leaves and stems daily for those egg clusters, and carefully remove and dispose of them into a bucket of soapy water.

Dark oval eggs clustered on the underside of a squash leaf.
If the leaf is infested even more than this…. just pull the whole leaf and dispose of it.

Babies or Nymphs

Grey squash bug nymphs crawling over a mature zucchini.
These guys are fast! I managed to get a photo of these nymphs and one adult (on the right side of the zucchini) before they skittered away.

You will also want to look for newly hatched babies, who tend to feed together in groups, again on the undersides of leaves. Carefully remove and dispose of them as well.

(Because seedlings have almost no defense against squash bugs, it is recommended that you only set out established, mature plants that you’ve either grown from seed indoors or purchased from a nursery.)

Eliminate Hiding Places

Unfortunately, because squash bugs tend to be a problem in areas that do not have severely harsh winters, chances are, you’ll still be dealing with them season after season, even though you do your best to search for and remove eggs and nymphs.

Therefore, in addition to a regular “search & destroy” regimen, you can further mitigate their population and damage by avoiding the use of mulch on the soil of these plants.

When it’s very warm, they tend to hang out at the base of the plant where it is cool and shady, so adding mulch will only give them more places to hide. (Instead, put down an inch or two of compost in the spring, which will keep weeds down, while feeding your plants as well.)

The ‘I’ Word (Insecticides)…;and Natural Alternatives

Lastly, while most of us prefer to avoid insecticides, even the most ardently organic grower has probably been tempted during a particularly severe infestation.

Always remember that if you use insecticides, while you may succeed in killing some of your pests, you will also be killing their natural enemies (i.e. the Techinid Fly, the most notable natural enemy of the squash bug), which could actually perpetuate the situation.

Instead, here are two highly effective, natural alternatives:

Diatomaceous Earth: On a microscopic level, this natural product is much like shards of glass to an insect. Sprinkle it around the base of the plant, and when the squash bugs attempt to cross over it to get to the plant, the DE will lacerate the hide of the bug, causing it to dehydrate and die.

Note: DE will not harm earthworms, but can harm honey bees, so apply only when bees aren’t present (evening and early morning), and do not apply it on or near any blossoms.

Flowering Plants: Plant flowering plants, such as dill and daisies, alongside your winter squash. This will attract the Techinid Fly, who is your best ally in the fight!

In Summary

  • Remove all garden debris (host plants) at the end of the season.
  • Conduct daily inspections/removals of eggs and nymphs.
  • Avoid mulching winter squash plants; use a layer of compost instead.
  • Plant flowering plants with your squash to attract the squash bug’s natural enemy.

Most importantly, regularly remind yourself (and your fellow gardeners) that bugs are an important part of gardening! Simply understanding that not all bugs are bad goes a long way in our efforts to achieve our harvest goals! ~Karen

About Karen

A picture of Karen from Love Your Land.

Karen is a wife, mother, business owner, gardener, canner, and the owner of “Love Your Land.”

Karen understands that gardening in Northern Colorado is seemingly a fleeting moment in time, so join her on Facebook for daily tips, tricks, and discussions, and on Love your Land You Tube for weekly how-to videos on how to extend a 3-month grow season into a 9-month grow season!

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