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Squash Bug Prevention & Organic Control

If a healthy squash plant suddenly wilts, turn over a few leaves and you might see a squash bug’s distinctive bronze oval eggs. Your fears about your squash plants are confirmed! What should you do now? (Spoiler: Don’t reach for a pesticide!) Although squash bugs are notorious for wreaking havoc on squash plants, squash bug prevention and organic control are possible with the right approach. I’ll teach you how.

Squash Bug Prevention & Organic Control

Identifying Squash Bugs in the Garden

Before you can tackle squash bugs, it’s essential to know what you’re up against. Here’s what to look for:

Squash bug eggs & nymphs
Squash Bug Eggs & Nymphs
  • Adults are about half an inch (1.2cm) long, winged, with a grayish-brown body and flat back covered in fine dark hairs. As a defense, they give off an unpleasant odor. 
  • Nymphs (young squash bugs) are smaller, wingless, greenish-gray, and similar in shape to adults. They often cluster together.
  • Egg clusters are oval-shaped and copper-colored and usually found on the undersides of leaves. 

How Do Squash Bugs Damage Plants?

Adults and nymphs use their piercing mouth parts to suck plant juices from cucurbit crops, which include summer squash, winter squash, cucumbers, gourds, and melons. Severely affected plants’ leaves and shoots turn black, die back, and fail to produce fruit.  

Squash Bug Prevention & Organic Control

Organic Methods to Control and Eliminate Squash Bugs

Unfortunately, squash bugs are worthy opponents and usually require multiple methods to control them. If you do nothing, squash bugs multiply rapidly and are difficult to eradicate. Combining the following practices can be effective for squash bug prevention and organic control.


Attract Natural Predators of Squash Bugs

The tachinid fly is a natural predator of squash bugs and can be helpful in squash bug prevention and organic control. Plant a wide variety of nectar and food options to encourage tachinid flies to reside in your garden. Good plant choices to attract tachinid flies include rudbeckia, chamomile, cilantro, cosmos, dill, feverfew, borage, alyssum, and oregano.1 (Click on the plant name to read articles with planting information for each crop.)

This article explains more about how to attract beneficial insects to your garden.

Tachinid Fly
Tachinid Fly

Unfortunately, unlike other pests, squash bugs are not easily controlled by beneficial insects alone. Once spotted in the garden, their control requires some work on our part. 



Practice Companion Planting for Squash Bug Prevention and Organic Control

Plant nasturtiums among your squash plants to help with squash bug prevention and organic control. An Iowa State University study found that planting nasturtiums among summer squash significantly decreased their numbers.2 Learn how to grow nasturtiums in this blog post.

Squash Bug Prevention & Organic Control

Blue Hubbard squash is especially appealing to squash bugs. Use this fact to your advantage and plant it as a trap crop.

Blue Hubbard Squash
Blue Hubbard Squash

To do this effectively, you must plant blue Hubbard squash three or four weeks before your desired varieties. Plant blue Hubbard several feet (1-2 m) away from other varieties on the outskirts of your vegetable garden.3 Click here for blue Hubbard squash seeds. Learn more about how to grow winter squash in this blog post.


Hand-pick all Stages of Squash Bugs Daily

While it may not be the most glamorous method, hand-picking is very effective. Early detection is crucial. Check your plants daily for all stages of squash bugs; if spotted, keep a bucket of soapy water near your plant. Check the plants often and dispose of the eggs, bugs, and nymphs in the soapy water. They are a little slower in the morning–that’s when I like to do my daily check. 

Squash Bug Prevention & Organic Control

Use Traps

Trapping can be an effective organic control method for squash bugs. To do this, lay out a wooden board in your garden. Squash bugs will congregate underneath them overnight. In the morning, collect and dispose of the squash bugs.

Remove Plants if Numbers Climb

If your infestation is out of control, remove and destroy affected plants to prevent the bugs from spreading. Do not add to compost. Keep that bucket of soapy water handy, and check the area around the removed plant and under the mulch. I like to use the hose to soak out any remaining stragglers. 


How to Prevent Future Infestations of Squash Bugs


Rotate Your Crops to Prevent Squash Bug Infestations

Don’t plant members of the cucurbit family in the same spot year after year. Adults overwinter in garden debris and emerge to mate and lay eggs in the spring. If you grow in the same location, you make it easy for them. Rotate your crops to prevent squash bugs from building up in the soil.

Clean Up Garden Debris

To reduce overwintering sites, remove plant debris during the growing season and clean up all plant matter when the season ends.

Maintain Healthy Plants

Healthy, well-watered plants are more resilient to pest damage. Keep your plants in top shape to reduce the impact of squash bugs.

Squash bugs don’t have to spell disaster for your garden. With these organic methods and preventative measures, you can keep your plants healthy and thriving. Do you have any tips or success stories? I’d love to hear them. 


Sources and Further Reading About Organic Control and Prevention of Squash Bugs:

Reference

  1. Attracting Beneficial Bugs to Your Garden, A Natural Approach to Pest Control, Jessica Walliser.
  2. Plant Partners, Science-Based Companion Planting Strategies for the Vegetable Garden, Jessica Walliser.
  3. Plant Partners, Science-Based Companion Planting Strategies for the Vegetable Garden, Jessica Walliser.

Further Reading


If this post about the organic control and prevention of squash bugs was helpful, please share it.

Jerry Swan

Monday 17th of June 2024

I have been gardening at a community garden in Las Vegas (zone 9b) for a number of years. Squash bugs were always an issue in my beds. I used many of the techniques that you cited, but it was always a challenge. Then, a local master gardener suggested that I wouldn't have an issue with squash bugs if I waited until after Father's Day to plant my zucchini. I was dubious, but decided to try it. To my amazement, it worked. I have been following this planting schedule for eight years and squash bugs are not a significant issue in my raised beds. Other gardeners who continue to plant earlier in the season continue to deal with squash bugs. I love your newsletter and your Perpetual Planting Calendar has become my lesson plan for year-round gardening. Thank You!!

Jerry Swan

Thursday 20th of June 2024

@Angela Judd, Our Spring and Fall frost dates are comparable to yours. Our monsoon season is primarily an elevation of humidity levels rather than a significant increase in rainfall. Your annual precipitation (7+ inches) is nearly twice as much as ours (4 inches). This is my first full year using your planting calendar. Thus far, everything that I have direct sown based on your calendar has germinated and matured at rates consistent with the information provided by the seed companies - lettuce, beans (bush, pole, yard long), okra, Japanese cucumber, bok choy, parsley, spinach, cilantro, sugar snap peas, Armenian cucumbers, dill, mustard, edamame. The same is true for varieties that are transplanted – tomatoes, eggplant, kohlrabi, peppers, sweet potatoes. Your calendar has worked very well for me and I plan to continue using it.

Angela Judd

Wednesday 19th of June 2024

Great tip, thank you. I'm interested to hear what differences you've noted for your climate vs. my calendar. People ask me quite often about if if works for Las Vegas.