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Squash vine borers are probably the #1 killer of squash plants. If you’ve been plagued with them and want to find out how to get rid of squash vine borers, you’re in the right place!
In this post, I’m going to show you ways to get rid of squash vine borers without using dangerous pesticides and chemicals in your home garden.
You can control squash vine borers naturally!
What Is A Squash Vine Borer?
Squash vine borers are these ugly white larvae that eat your squash vines and other soft vine vegetables from the inside out.
You can have a perfectly healthy squash or pumpkin plant one day, only to find it all wilted and dying the next. But there is hope….don’t just give up yet.
Plants Squash Vine Borers Are Attracted To
Adult squash vine borers, Melittia satyriniformis, are attracted to the color yellow. So they commonly are attracted to squash, pumpkins, gourds, cucumbers, and melons. They enjoy the hollow stems of these plants.
Their least favorite is the cucumber and melons.
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How To Identify Squash Vine Borers
The adult moth is quite gorgeous, but it can wreak havoc on squash and pumpkins.
Adult Squash Vine Borer moths are about 1/2 inch long. Their abdomen is a bright orange with black dots. They have 2 sets of wings: the front set is a clear-metallic green, and the back set is totally clear. These are hard to see because they fold when the moth is resting.
Their eggs are brown, flat, and about 1/25 inch long. The adult moth lays them out singly on the stems of soft vine plants.
The larvae are about 1 inch long, white with wrinkles or band-like rings around their whole body, and have brown heads.
Squash Vine Borer Life cycle
Adult
Adult pupae overwinter in the soil and emerge from a squash vine borer cocoon as full-grown moths Melittia curcurbitae, in mid-summer, about mid-June-July.
They flit around and lay eggs singly on the vines of the plant. A single moth can lay up to 150 eggs in a season.
Eggs
The eggs hatch within 2 weeks after being laid, and a larva or squash borer worm emerges.
Larvae
Squash vine larvae bore into the soft stem and feed off the innards of the vine, blocking the water flow of it and killing it from the inside out. It feeds for 4-6 weeks and grows to about 1-2 inches long.
Pupae
It then exits the stem and burrows itself into the soil to pupate, where it remains until the next summer.
The good news is there is only 1 generation per year.
How To Identify Squash Vine Borer Damage and Infestation
As I said, one day you have these lush green, healthy plants in the garden, only to go out the next day to find them wilted and dying.
This happened this year with my gourds. Lush, loaded with blooms, and then the next day, all wilted and shriveled up.
Of course, both squash and pumpkins wilt during the heat of the day, but if this problem persists, it does need to be checked closely as they can destroy a crop in a matter of a couple of days.
When this happens, look closely near the bottom or base of the plant for holes that have been bored into them.
You may find sawdust or a yellowish-green-like substance, frass, in little piles on the stem. This is exactly the hole you are looking for. This is where the larvae have bored into the stem.
It will be soft and start to rot as the larva is feeding on it. This cuts off the water flow to the rest of the plant, and it dies quickly.
A single plant can have more than 1 squash vine borer larvae in it.
How to Get Rid of Squash Vine Borers Naturally
So how do you kill squash vine borers? It takes a little effort, but it can be done.
Don’t get discouraged if this happens to you. There are several ways to control or get rid of squash borers, and we’ll go through each one of them.
Before we begin, let me say that, unfortunately, once the larvae are inside the stem, chemicals really have no effect on them. But like I said, a little effort, and you can get rid of them.
So will Diatemaceious Earth kill squash vine borers? It has to be placed on the leaves in order to harm or kill the adult moth. You may also harm beneficial insects too when you do this. So I would not recommend it for controlling squash vine borers.
How to Trap and Kill Adult Squash Vine Borer Moths
1. Trapping or Killing the Squash Vine Borer Moth
The adult moth is out and about during the day, unlike other moths that fly around at night. Early in the morning, if you are lucky, you will find them resting on top of the large leaves. They are quite slow and can be smashed then if you are quick enough to find them.
They are easily spotted, appearing to look a lot like a wasp but with a bright orange abdomen. Also, when they fly, you can hear their double wings roaring.
2. Homemade Squash Vine Borer Traps
As I said earlier, squash borer moths are attracted to the color yellow. You can make your own trap by getting a yellow pail, bowl, or cup of water in the garden. The moth is attracted to the color and drowns in the water.
I’ll be honest; I have not tried this method. My friend says it works great. She says it is a good way to monitor for them, at the least.
Of course, if you prefer not to DIY a homemade trap, you can buy one from the market, such as this one.
3. Plant Trap Crops
If you plant decoy plants 2-3 weeks earlier than the ones you plan to harvest will help. They will bloom first, and this will help to give you a good indicator of having them around.
Last season, I had none. This year, I’ve battled them all season. You just never know.
How to kill squash Vine borer larvae inside plant stems
Next, if the moths have laid their eggs and hatched and the larvae are inside the plant stems, there is still hope.
1. Surgically remove larvae from The Stem
Look for the greenish-yellow sawdust-like stuff, “frass.” This is specifically where the larvae had entered. Here is what you do….
Using a sharp knife, box cutter, or I use an Olfa Knife, you are going to do a squash vine borer removal. Gently, cut a tiny slit and carefully look inside to find the worm. You can either cut it out completely or just by cutting the worm itself, and it will die.
Once you slit the vine open, cover it over with moist soil in an effort to allow it to grow more roots. Keep the plant watered well to give it every chance to survive.
2. Run a Wire up the center of the stem
This may be less invasive to your plant. The idea is to stab the larvae to cause them to die. But I like to know for sure that it is dead. I want to see it out of the plant and dead. So it can cause no more destruction.
3. Use Bt
You can spray the plant with Bt, Bacillus thuringiensis, and it might help. Make not the BT is more effective on the egg hatch before it bores inside rather than the larva. Bt has to be injested, so once it enters the stem, it is protected from sprays. Key is getting them before the bore into the stems.
Does Neem oil kill squash vine borers? It will kill the babies as they are eating their way inside the vines, but once inside, it has no effect on them.
How to Prevent Squash Vine Borers
Of course, if squash vine borers are a problem in your garden, you can do these few things in advance to help with preventing them.
1. Mulch around the plant stems
Cover the stem as it grows with mulch. This will help to keep squash borer moths from laying eggs on the stems.
2. Wrap the Stem with Aluminum Foil
Use pantyhose and aluminum to protect the stem. To do this, gently wrap the first foot or so of the stem from the base up. Tuck the pantyhose end into the wrap to hold it secure.
Next, use several 3-4 inch wide strips of aluminum foil, and wrap it around the pantyhose securely. This will prevent the adult squash borer moth from laying eggs.
3. Use Row Covers
This can be done when the squash is young, but of course, they do get really large and cover a lot of ground.
Using a lightweight floating row cover to prevent the adult squash borers moths from laying eggs on the vines will help to control the moths.
4. Plant a late crop
Squash vine borers stop laying eggs in late July. Plant a late crop when they have finished laying eggs.
5. Plants resistant to Squash Vine Borers
Squash vine borers will lay their eggs on any stem of a hollow vegetable. Not only squash and pumpkins but they are also attracted to gourds and any vegetable in the cucurbits family.
They do have their least favorites, though:
- Butternut Squash
- Italian Tromboncinos
You can Control Squash Vine Borers
As I mentioned earlier, preparing ahead for them can help to keep them controlled or even get rid of them completely.
Look at soft stem squashes, pumpkins and gourds closely daily. They will be down near the base. Destroy the eggs before they can hatch.
Set up the yellow traps to know if you have them in your garden. If you catch one, you know to be on an even higher alert looking for them and their eggs.
Have you had issues with squash vine borers in your area? If so, what do you do to get rid of them?
More Garden Pest Tips:
- 15 Ways to Get Rid of Horn Worms
- How to Naturally Control Yellow Jackets
- 31 Best Flowers to Grow For Gardens to Attract Insects
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Dianne Hadorn is the owner of Hidden Springs Homestead nestled in the hills of East Tennessee. She is a Master Gardener and enjoys helping others learn how to grow and preserve their own food and sharing tips for living a more sustainable life.
Dianne, have you tried the sticky traps you recommended in this article? If so, did they work? It appears that they do not contain pheronome to actually attract the moths, so I’m wondering if the SVB moth is still attracted to it?
Hi Susan,
I haven’t used them, as mentioned in the article. I do the deep mulching and use aluminum foil around mine. I think the deep mulch works really well for me or has so far. My friend, Anne, uses them and likes them, but I don’t like the idea of catching beneficial insects on them too. I hope this helps,
Dianne
SVB eggs 6’ up on Tromboncino Squash not just at the base so they clearly are adaptable!
I am in central CT, and have been using the surgical method for years. Yes, it works! Once I see the Frass, I slit the stem lengthwise, gently open the stem until I come to the “worm”, destroy it, then cover it over with a mound of dirt, being careful to cover beyond the cut, then water it in. It always re-roots and survives, saving the rest of the plant. I have also planted late in the season, mid July and haven’t been bothered by the borer. I like the idea of using a floating row cover. I will have to do that this year. Thank you for your very thorough explanation of Squash vine borers. I learned some things I did not know before!
In Nacogdoches, TX, I saw squash vind borer, SVB, flitting around the zucchini today, August 22. I think I am on my third generation of the season. Or maybe I just have some slow learners…
A late start this year, moving in May 6, constructing and filling raised beds. After noting moths sometime in June, (second generation?) I observed the eggs to be attached to the leaf stems as much as 6 inches from the stem at ground level. So far, my SVB larva haul from pumpkin (2), butternut and zucchini (several) has exceeded my zucchini harvest. (They look succulent?) Naw.
You should note the cut goes *with* the stem so a first-time hunter does not cut across the stem.
I have a hat pin that works well to extract the little buggers.
Yellow sticky traps have caught a lot of things, but not SVB moths.
I have seen the sawdust like material. Is frass the gooey material in 1/16th inch spheres or is that just the fresh version?
Something like Dawn detergent will reduce the surface tension of the water and let the moths drown easier, unless it might repel them. An experiment to try. Beer works well for slugs…
Hi Mark,
Yes, frass is the gooey stuff. It does shrink some as it dries. Great observation on your garden.
I grew yellow and zucchini summer squash this year and also had problems with the borer. Since I was trellising my plants, after I did surgery to remove active grubs, I could not bury the surgical sites. I was, however, able to use repurposed large yogurt containers filled with dirt as “protective sleeves” on the areas I had cut. I opened a stem-sized hole on the bottom of the container, slit the container up the side, attached it to the injured site, and filled with garden soil. I kept the container closed with some heavy duty tape. I watered these sleeves throughout the rest of the season. When I cleaned out the garden, it was evident from the amount of roots filling the container of the “still alive” squash plants, that this method worked.
Hi Dee Dee
Just WOW!! Love the ingenuity of this. Thanks for sharing.
This is my first time planting a garden, they destroyed my zucchini squash while my spaghetti squash is growing beautifully. It is mid July, I will try again with the Yellow cup of water. Thanks for the knowledge
Hi Ree,
I’m so sorry. They are terrible I know. I lost 1 this year myself. I check it closely one day and all seemed great, but got up the next morning to find it dead and lifeless. I dug out 2 large ones and the chickens got a tiny treat.
So it appears I would have to dig up the entire plant to be able to cover the first foot of the stem with aluminum foil… can that be right?
Hi Dena,
No, I’m sorry this didn’t seem clear. No need to “dig up” the plant. The moth lays it’s eggs near the bottom of the stem near the soil line or a bit above the soil. If you carefully wrap from the soil line up will help a lot. I’ve used this method and it did help A LOT.
Sorry for the confusion,
Dianne
Thank you. I’ve been dealing with this problem for 10 years with no solution in sight. Don’t want to use the yellow stickie paper because of possible damage to bees. I will try the aluminum foil (if it ever stops raining here!). Thanks again.
How do I get rid of squash borers permanently
Hi Karen,
Unfortunately, there is no ‘permanent’ way to get rid of them. They overwinter in the soil and come out the next spring. I’d suggest rotating your garden annually and not planting squash in the same area but every 3rd year. This is hard to do if you don’t have the space.
I have used yellow sticky paper for years and the bees ignore it,
Thank you. I’ve been dealing with this problem for 10 years with no solution in sight. Don’t want to use the yellow stickie paper because of possible damage to bees. I will try the aluminum foil (if it ever stops raining here!). Thanks again.
Thank you for this post! I have to do “surgery” today on three beautiful Candy Roaster squash vines and I’m not looking forward to it, but you’ve given me more hope than I had before!
Rachel,
I’m so happy to help. It is very frustrating to have these things destroy our delicious squashes. But stay on top of it, you will need to care for them closely now. Once you make the incision, be sure to cover it well with good rich soil and compost.
Good Luck,
Dianne