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Writer's pictureAndy Hemmer

Diatomaceous Earth for Squash Bugs

Updated: Jul 16


squash bugs on a squash

Gardening can be a rewarding and therapeutic thing to do, but it often comes with its fair share of challenges during the growing season. One nuisance for many gardeners is the squash bug, like stink bugs and japanese beetles, an unwelcome visitor that can wreak havoc on squash plants and other plants in your garden. While chemical pesticides may offer a quick fix for the insect, pest control methods with chemicals can also harm beneficial insects and have potential health risks for humans. Fortunately, there's a natural alternative that's gaining popularity among environmentally-conscious gardeners: diatomaceous earth.



What is a Squash Bug?

Adult squash bugs (Anasa tristis), like stink bugs, are common garden pests that belong to the family Coreidae. They are particularly fond of squash plants, including zucchini, pumpkins, and cucumbers, but may also feed on other members of the cucurbit family. Squash bugs damage plants in your garden by sucking sap from leaves, stems, and fruit, leading to wilting, yellowing, turning brown, and ultimately plant death if left unchecked. Really none of those plants are resistant to squash bugs. Squash bugs have a life cycle of six to eight weeks. This life cycle gives them plenty of time to repopulate causing a real headache.



Where Can I Locate a Squash Bug?

Squash bugs are most commonly found in regions with warm climates, although they can be found in gardens across North America. They tend to congregate on the undersides of leaves and along the stems of squash plants, where they feed and may lay their eggs! In addition to squash plants, squash bugs may also be found hiding in nearby vegetation, mulch, or garden debris.



What Does a Squash Bug Look Like?

Adult squash bugs are about 1/2 to 5/8 inch long and have a distinctive shield-shaped body that is dark brown or grayish-black in color. They have long, slender antennae and legs, and their bodies are covered in small, flattened hairs. Squash bug nymphs, after their eggs hatch, are smaller and lighter in color, ranging from pale green to grayish-white. They also have distinct black legs and antennae. A squash bug egg is shiny, oval in shape, and are laid in small groups usually on the underside of leaves.

squash bugs on squash plant


What is Diatomaceous Earth?

Diatomaceous earth (DE) is a naturally occurring sedimentary rock made from the fossilized remains of diatoms, a type of hard-shelled algae. It is typically ground into a fine powder and used in various applications, including as a natural pesticide in preventing squash bug infestations. Diatomaceous earth is completely non-toxic and the ultimate alternative to using chemical pesticides.

diatomaceous earth spilling out of plastic bag


Benefits of Using Diatomaceous Earth:


  1. Environmentally Friendly: Unlike synthetic pesticides, diatomaceous earth is non-toxic to humans, pets, and beneficial insects such as bees and ladybugs.

  2. Long-Lasting: Once applied, DE remains effective as long as it remains dry, providing ongoing protection against squash bugs.

  3. Safe for Organic Gardening: Diatomaceous earth is approved for use in organic gardening by many certification bodies, making it a preferred choice for those following organic gardening practices.

  4. Versatile: In addition to controlling squash bugs, DE can also help deter other garden pests like aphids, ants, and beetles.




How to Use Diatomaceous Earth for Squash Bugs:


  1. Identify Problem Areas: Inspect your squash plants regularly for signs of squash bug infestation, such as wilting leaves, egg clusters on the undersides of leaves, and adult bugs congregating around the base of plants.

  2. Apply DE: Using a dust applicator or simply sprinkling it by hand, apply a thin layer of diatomaceous earth around the base of affected plants, focusing on the stems and soil surface around the center stem

  3. Reapply as Needed: After rain or watering, reapply the diatomaceous earth as it may become less effective when wet. Monitor the plants regularly and reapply DE as necessary until the squash bug population is under control. If you are using soapy water to wash your plants, please allow it to dry before application of DE.


We recommend diatomaceous earth to kill squash bugs in your garden on your plants. Other than hand picking and planting squash that are resistant to these bugs, like the royal acorn squash, or using row covers, this is the perfect product to install in your garden pest management system and should be considered something to use synergistically with picking them and row covers. Please see below for some products that will aid you in your battle to eradicate them.




Diatomaceous earth offers a safe, effective, and environmentally friendly solution to combat squash bugs in the garden. By harnessing the power of this natural substance, gardeners can protect their squash plants without resorting to harmful chemical pesticides. So, the next time you find yourself facing a squash bug invasion, consider reaching for diatomaceous earth and let nature take care of the rest. Your squash plants—and the ecosystem—will thank you for it.

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