Operation Squish: Keeping Squash Bugs Out of the Garden


Summer squash and zucchini in a bowl


I love zucchini. I love it. I’m certain that I could eat zucchini every day for the entire summer and not grow weary of it. While its true that the blue ribbon crop of our 2011 garden was our abundant Roma Tomatoes, my personal treasure was the zucchini. I gave it special attention and chirped with glee every time I picked one.

That’s why I was so distressed in mid-July when my previously healthy, well-watered prizes began to wilt. After a bit research I discovered the culprit – vine borers. They had attacked the roots/stems of my beloved plants and I was beginning to loose them. There was no way I was giving up my precious zucchini to some insect the size of my little toe! I did even more research and discovered the following fix:

  • Remove the vine borer if possible
  • Pile generous amounts of soil over the affected area (repeat as necessary)
  • Water heavily

After following these tips, my zucchini were saved and were still producing in late September when I ripped them out to replace them with beans.

Now I know what you’re asking yourself: “If you love zucchini that much, and they were still producing, why did you take them out?” Two devilish words: Squash bugs.

About 3 weeks after I transplanted my zucchini into the garden I direct-seeded some summer squash (which I love nearly as much). Just as they were starting to produce fruit, the entire bed became invaded by a host of squash bugs. They were everywhere and, when all was said and done, I only got two tiny squashes from a dozen plants. Boo!

With much disappointment, I pulled out the summer squash and composted it. That was a big mistake! The squash bugs then migrated over several beds and started attacking the zucchini. Thus began Operation Squish…

I read that you could hand-pick the bugs and drop them in water with a touch of dish soap (to break the water’s tension). So last summer I spent a considerable amount of time drowning bugs… even babies… [Don’t judge me.] It helped to lessen the assault, but of course, my enemies had the advantage and I never truly got an edge.

During my research phase I read many accounts of other gardeners who said that squash bugs continually wiped out their squash/zucchini year after year. Many of them had given up on growing squash entirely. There is no way that can happen here – not with my precious zucchini. So, after much research and thought, here is the play book for Operation Squish 2012: Keeping Squash Bugs Out of the Garden:

  1. No Mulch. While most of my garden plants benefit from mulch, I’ll be skipping it with the zucchini and summer squash. Why? Because squash bugs like to develop and hide beneath it. No way bad boys… I want you where I can seRow cover over zucchini and summer squashe you…
  2. Row cover. From what I read, one of the best ways to keep squash bugs at bay is to simply deny them admittance to the garden altogether via a row cover. Using hoops made of PVC pipe, I’ll be draping a polythene, UVA-protection plastic over the beds and securing it tightly around the bed. Since zucchini/summer squash can grow in soil temperatures up to 90*, I’ll be using an indoor/outdoor, water-resistant thermometer placed directly into the bed. Here’s the one I purchased.
  3. Remove eggs. If I find squash bug eggs (orangey brown clusters) on the underside of leaves, I’ll be removing them by hand.
  4. Neem oil. According to Wikipedia, “Neem oil is a vegetable oil pressed from the fruits and seeds of the neem (Azadirachta indica), an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics. It is the most important of the commercially available products of neem for organic farming and medicines.” Using a recipe I found here, I’ll be creating an organic garlic and neem oil juice to spray on the bed.  The recipe is as follows.
Squash Bug Eggs on Underside of Leaf

Squash Bug Eggs

Organic Garlic Juice Pesticide for Squash Bugs

4tsp baking soda (anti fungal properties, also stops powdery mildew type problems)

1tsp vegetable oil (smothers) Neem oil would work well here. The amount could be doubled.

1tsp soap (emulsifier/sticker) Best to use a natural soap such as Dr. Bronner’s.

1 to 2 tbl garlic juice (kills)

Juice: 1 med bulb of garlic blended with 1 to 2 cups of water. Let sit a minimum of 15 minutes and strain.

 Add concentrate to a gallon of water and spray liberally. Repeat as often as needed to drive off or kill the squash bugs.

Of course the whole point is to keep squash bugs out to begin with. If that’s not possible, I found some great tips on eliminating them post-arrival at the University of Minnesota Extension page on Squash Bugs in Home Gardens. Here are the items I haven’t already mentioned:

  • Maintain healthy, vigorous plants through proper fertilization and watering to help limit squash bug damage.
  • Trap squash bugs by laying out boards or pieces of newspaper. Squash bugs will congregate under the boards at night, and then can be collected and destroyed in the morning.
  • Remove plant debris around the garden during the growing season to reduce the potential harborages where squash bugs may hide. Clean up cucurbits and other plant matter around the garden in the fall to reduce the number of overwintering sites.

To be completely scientific about this process, I would need to have a control group with no changes whatsoever. But my crops are way to precious to take any chances. Instead, I’m going to have the following groups:

  1. No mulch, row cover, organic garlic juice pesticide (with neem oil)
  2. No mulch, row cover, organic garlic juice pesticide (with vegetable oil)
  3. No mulch, row cover

I’ll let you know what the results of Operation Squish are so that you can put the best tactics to work in your home garden. Stay tuned for updates!

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