Squash Vine Borer: How To Prevent, Protect, And Get Rid Of Them

Have you ever experienced this?  One day you have a healthy squash plant, then the next day, you find your plant limp and collapsed on the ground?  That could mean the dreaded squash vine borer has attacked your plants. 

First of all, just let me say – I HATE squash vine borers. I have dealt with them every year and some years more than once.  So far before this year, I had lost the battle with squash vine borers (also known as melittia cucurbitae) more than I have won. 

But, this following year, I have tried a few methods to prevent, protect, and get rid of squash vine borers, and at this point, it looks like they’re working!   That’s why I decided to share my success in adult squash vine borer treatment with you!

Squash Vine Borer:  How To Prevent, Protect, And Get Rid Of Them

Squash vine borers are born caterpillar type worms that come from eggs laid on the stems, leaf stalks, and/or leaves of your squash and zucchini plants by the adult squash borer moth.  Now, these are not squash bug eggs, and those are laid all in a row or set of tight rows by a different bug. 

No, quite the opposite of the squash bug eggs, these are laid willy-nilly all over the place, and you have to search every inch of the plants to find them.  I have checked my plants as many as 3 times a day and still missed some.

THIS is the moth you’ll be battling that is laying eggs all over your squash, zucchini, and sometimes cucumber plants!

Once those eggs hatch, they immediately burrow into the stem of your plant and eat their way down the stem to the rest of the plant on the INSIDE, so the only way you know they are there is when you see tiny entrance holes in the stem or what is known as “frass” which looks like wet sawdust and is actually their feces… gross…

If you were to cut open the stem and find one (or more), you would see that they are white grub/caterpillar looking worms with a brown head.

As I mentioned earlier, I have battled these awful things here more than once.  I live in Texas, and they start laying the eggs in Spring or early summer and can still laying them in November and December. 

Other places in the country say they are gone once you hit the late June or Fourth Of July.  So, you’ll need to check your zone to see when and if (because not all areas of the country have these, yet) they show up where you are.

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Signs Of Squash Vine Borer

Once you notice your squash plant wilted in your garden, take a closer look at the plant.  Start at the base of the plant and stem and work upward and outward.

If you notice the small holes in the base of plants or stem, even the “frass,” or you see the eggs, which are copper colored and flat, you can pretty much assume you have one or more squash vines borers in the stem, and they have compromised your plant.

Once the squash vine borer adults lay their eggs on your plant and their larval stage worm burrows into the stem of the host plant, the injury prevents the plant from taking up any nutrients or water.

Due to a lack of water and nutrients, the plan will start to wilt, even if you are consistently watering or using fertilizer.

Just because there are squash borers inside your plant doesn’t mean that it will certainly die!  If you catch it soon enough, there are things you can try.

It’s easy to get rid of these insect pests using simple, safe, and organic pest control methods.  There is even a homemade pesticide that you can make in the comfort of your home!

How To Get Rid Of Squash Vine Borers

Locating the Squash Vine Borer

Removing these squash vine borers is pretty easy.  Carefully slice open the vine lengthwise at the entry or where you see the “frass,” and carefully open the stem up.  Make sure to cut just above the spot where you can see the sawdust or the hole.

After opening the vine, you may see the worm right away, or you need to search around for it.   Once you spot the squash vine borer, pull it out with a needle or sharp object and then squash it.  You may also drop it in soapy water.

Once you have retrieved the squash bugs (always make sure you don’t leave one in there, there could be more than one) from inside the stem, if the slit you made is close enough to the ground to cover it back over with moist soil, do that.  Make sure it has enough soil and water to allow the stem to root and recover. 

If the slit is higher on the plant, carefully close it back up and tape it with electrical tape, a band-aid, some medical tape, or anything that will weather ok.  Be sure not to tape it too tightly so it can expand.

A Less Invasive Method

Another method I have found VERY effective, and the one I plan to continue using, is BT, also known as Bacillus Thuringiensis.

“Bt is a bacterium that is not toxic to humans or other mammals but is toxic to certain insects when ingested. … Over two decades of review, the EPA and numerous scientific bodies have consistently found that Bt and engineered Bt-crops are not harmful to humans.”

Entomological Society of America

BT is very useful you can do is use it as a spray on your plants, which I also do, but it’s not as effective as the next method.

I went to my local feed store and bought needles for injecting the BT into the main stem of the plant. The needles for me were about $0.40 each. You’ll want to change them between each plant and then sterilize them well afterward before reusing.

Once the flowers begin blooming on your plants, that’s when you want to begin injecting the stem weekly. If you see a vine borer has entered the stem, inject about 1 inch above. When they ingest the BT, it causes them to stop eating and die. Doing this a great way in getting rid of vine borers.

I did this in this previous season towards the end and had great success – the ones that got into my plant never caused them any harm, and I was able to harvest until the frost – which NEVER happens for me. After I started using it, I never lost another plant to Squash Vine Borers.

I prefer this method because 1. It works, 2. It’s inexpensive, and 3. It’s much better shooting a needle in my squash plant stems rather than slicing them open to remove the borers once they have entered the entire plant, and 4. I don’t have to inspect the plants 3 times a day and remove the reddish-brown eggs.

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Homemade Pest Control

Spraying an insecticide or pest control can also get rid of these garden pests.  However, using a commercial insecticide is harmful not only to these insects but also to beneficial insects and your family, too.  But there are non-toxic and safe pest control options!

Neem Oil Solution

Prepare The Following:

• 1 teaspoon neem oil
• 1/3 teaspoon mild soap
• 1-liter warm water
• Spray bottle

To Prepare:

1. Mix the neem oil, mild soap, and warm water.
2. Transfer the mix to a spray bottle.

Spray this oil solution all over the plant as often as needed.  Regular spraying can prevent these squash borers from laying eggs on your plants. 

This is my favorite garden sprayer, and it’s cheap at just $5!  I use it all the time.

How To Prevent Squash Vine Borers

Use Yellow Sticky Traps

If you are wondering how to prevent vine borers in your large or small garden, kill the adult moths before they lay their eggs and this is how to keep vine borers away.

These moths are active during the day.  They usually emerge from the soil surface.  Since these squash vine borer moths are attracted to the color yellow, using yellow sticky traps or pheromone traps can trap them.

You can also use yellow bowls.  Fill them with warm soapy water and leave them around your plants. This is another option for how to get rid of vine borers.

Cover Your Plants

Prevent squash vine borers by preventing squash vine borers moths from gaining access to your squash plants.

Cover your plants with floating row covers.  Make sure to anchor the covers so the moths will not quickly get underneath the plants.  Once the plants begin to flower, you can remove the row covers for pollination, or pollinate them yourself.

You can also create a barrier, so these borers cannot burrow into the squash stems.  Wrap the stems with nylon strips, pantyhose, or aluminum foil strips. 

Keep It Clean

If some plants are already infested with these pests, and you can’t help them, remove them immediately.  Place the infected plants in a garbage bag or plastic bag and dispose of them.

After harvesting the plants, clear away all the materials from the garden and start tilling them. Replace the soil to make sure that there are no vine borer larvae pupating in the soil. That should answer how to get rid of vine borers in soil.

Don’t plant summer squash in the same spot or soil for at least 3 years after a vine borer infestation.  Once the vine borers finish eating your plant, they burrow into the soil underneath and overwinter there and then emerge next Spring or early July as the moth that lays the eggs. 

So, be careful to make sure there are none in your soil by tilling at least 2 inches deep and bringing the overwintering pests up to the surface so the sun can kill them.

FAQ: Squash Vine Borers

Q: What plants repel squash vine borers?

Answer: Plants that deter squash vine borers, include mint, basil, onion, and parsley radishes, are also known to repel the moths.

Q: How to prevent vine borers?

Answer: For how to prevent squash vine borers, the moths are attracted to the color yellow. Using yellow sticky traps or pheromone traps can trap them. You can also cover your plants with floating row covers to protect squash from vine borers. And that’s how to avoid vine borers.

Q: How to kill squash vine borers?

Answer: For how to kill squash vine borers, an effective method is to make a neem oil spray by mixing 1 teaspoon neem oil1/3 teaspoon mild soap1 liter warm water together and spraying your affected plant as often as needed.

Q: What insecticide kills squash vine borers?

Answer: An insecticide that kills squash vine borers is harmful since spraying an insecticide or pest control can also eliminate good bugs. Another solution how to stop vine borers is to go to your local feed store and buy needles for injecting the BT into the plants’ main stem. When they ingest the BT, it causes them to stop eating and die.

Q: How to stop squash vine borers?

Answer: For how do you get rid of vine borers? Harvest the infected plants, then clear away all the materials from the garden and start tilling them. Replace the soil to ensure no vine borer larvae are pupating in the soil.

Do you have any natural and homemade pest control strategies with proven results in your garden?  I would love to hear from you!

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