Squash borers are one of the most frustrating pests for many gardeners. In this post, you’ll learn all about their feeding habits, life cycle, where they come from, the damage they do, and the signs of infestation. Then I’ll show you exactly how to get rid of squash vine borers organically, and prevent them from coming back.
If you’ve ever tried growing squash in an area where squash vine borers are present, you know how frustrating it can be to find those ugly white worms inside of your plants. But there’s no reason to pull the plants, or stop growing them all together!
Yes, you can get rid of squash borers, and prevent them from coming back again. Once you understand their life cycle, and know all of the signs to look out for, it’s actually pretty easy to control and prevent them.
Here’s what you’ll find in this guide for getting rid of squash vine borers…
- What Are Squash Vine Borers?
- What Do They Look Like?
- Squash Borer Life Cycle
- Where Do They Come From?
- What Do They Eat?
- Damage To Plants
- Signs Of Infestation
- How To Get Rid Of Them Organically
- How To Prevent Squash Vine Borers
What Are Squash Vine Borers?
Squash vine borers (also called “squash borers” or “squash worms”) are common pests of plants in the cucurbits family, and they are very destructive. These frustrating pests are the larvae of the squash borer bug.
They get their common name, “squash vine borer”, because they bore into the vines of the plant, eating them from the inside out. A trait that makes them impossible to see, and difficult to control.
Some people get squash borers and squash bugs confused. They are both common cucurbit plant pests, but they are not the same bug. You’ll only find squash borers inside of the plant. So, if you have bugs crawling all over your plants, those are squash bugs, and here’s how to get rid of them.
What Do Squash Borers Look Like?
Squash borers look like white worms. They have a black head and wrinkly bodies. They start out tiny, and grow to be about 1″ long.
The adults are a type of moth which, I hate to admit, is actually kinda pretty. They’re reddish-orange with black wings and black dots down the length of their back. They’re active during the day, and look like a wasp when they fly.
Squash Vine Borer Life Cycle
There are four stages in the squash borer life cycle: moth (adult), eggs, larvae (borer), and pupa. They overwinter in the soil in 1″ long reddish-brown colored cocoons. Adult moths emerge in late spring/early summer, and start laying eggs on nearby cucurbit plants shortly after.
The female squash borer moths lays her eggs at the base of the plant, where they will hatch 1-2 weeks later. The female moths can lay a lot of eggs, but the good news is that they’re only active for about a month (usually June-July).
Shortly after the eggs hatch, the tiny squash borers burrow into the stems. As they feast they grow larger, reaching their full size of about 1″ long in 2-4 weeks.
Once they are full-sized, they will leave the squash vine to pupate in the soil. Squash borers will form a cocoon in the soil, where they will remain until the following spring.
If you live in a cold climate like I do, the good news is that there’s only one generation of squash borers per year. But in warmer climates, there can two generations per year.
Where Do Squash Borers Come From?
Since the adults can fly, squash borers could come from anywhere. They’re naturally attracted to cucurbits, since that’s their main host plant.
If squash vine borer moths are present in your area of the world, and you’re growing any type of cucurbit plant, then it’s a sure bet they’ll find your garden. This is part of what makes it so hard to get rid of squash vine borers.
What Do Squash Vine Borers Eat?
The main host plant for the squash borer moth are plants in the cucurbitaceae family. Examples of cucurbitaceous vegetables include all types of squash (both summer and winter varieties), zucchini, pumpkins, gourds, as well as melons, luffa, and cucumber.
They do love squash plants the best though (hence their name). So, it’s much less common to find them feasting on cucumber and melon plants.
The good news is that the larvae is the only stage in their life cycle where they eat plants. They are harmless in both their adult and pupa stages.
It’s most common to find squash borers eating the insides of the vines. But sometimes they will find their way into the fruit too, and destroy it from the inside out (Gross!).
Squash Borer Damage To Plants
Since they eat the plants from the inside out, squash borer plant damage is difficult to spot. At first, you may notice what looks like yellow sawdust coming out of the vines. This is squash borer poop (also called frass).
Squash borers hollow out the vines and stems as they feed. So, once the damage becomes more severe, the vines will be mushy, and may even split open.
Unfortunately, they can also bore into the fruit, causing canker wounds or soft spots. At their worst, squash borers can feed on the vine until it’s completely severed, killing the plant.
Signs Of The Squash Borer
If a squash borer infestation is left untreated, the entire plant will eventually collapse and die. It’s important to get rid of squash vine borers before it gets that bad, so you’ll definitely need to know the signs to watch out for.
Squash vine borers are sneaky, and can go unnoticed for a very long time. Most people don’t know there’s a problem until their squash plants wilt or begin to die.
But don’t worry, it’s easy to spot an infestation once you know the telltale squash vine borer signs. Here are the main signs to look out for…
- Droopy leaves, or the entire plant has wilted
- Holes in the vine or stem
- Mushy yellow sawdust anywhere on the stem, vine, or the fruit
- The vine is mushy, split open, appears to be rotting, or is completely severed
- Canker wounds or soft spots on the fruit
- White worms inside squash fruit, stems, or vines
If your plant has any of these symptoms, then it’s time to take immediate action to get rid of squash borers as fast as possible.
How To Get Rid Of Squash Vine Borers
Don’t worry, just because there are squash borers inside of your plant doesn’t mean it has to die! With a little bit of work, you can save your plants, and your harvest.
It’s pretty easy to get rid of squash vine borers organically by using a simple, non-toxic, and very effective method that I like to call… digging those nasty suckers out of the vine.
Don’t worry, it sounds harder than it is. But it really is the only way to get them out of the plant. Here’s what you’ll need…
And here are the steps for getting rid of squash borers when they’re already inside the vine…
- Step 1: Slice open the vine – Carefully slice open a small part of the vine the long way using a sharp utility knife. Make a 1-2″ inch long cut just above the spot where you see the hole or sawdust mush.
- Step 2: Find the squash borers – Gently pry open the vine to look for the ugly white worm. You may spot it right away, or you might need to make the slit larger so you can search around for it.
- Step 3: Remove and kill them – Once you find a squash borer, pluck it out and kill it. You can simply squash it (pun intended!). Or, if that makes you too squeamish, then drop it into a bucket of soapy water (a few squirts of liquid soap in the water will do the trick). Sometimes it’s easier to just squish it inside of the vine than it is to remove it. That’s fine, squash borer guts won’t harm your plant.
- Step 4: Look for more squash vine borers – Continue inspecting the plant to look for signs of additional borers, and repeat steps 1-3 for each one that you find. There can be several of them inside of each vine.
- Step 5: Bury the vine – Once you’re sure you’ve removed all of the squash borers, bury the injured section of the vine in dirt. Squash vines will grow new roots under the soil, and the plant will become even stronger because of it.
Remember that squash borers can be different sizes, and the smaller ones can be much harder to spot than the big fat ones.
Also keep in mind that sometimes you’ll see signs that a squash borer is inside the vine, but you can’t find anything after you cut it open. Don’t be discouraged, maybe it already left the vine. Or maybe it was so small you squished it without seeing it. Just cover the injured part of the vine, and move on.
How To Prevent Squash Vine Borers
Since they are inside the plant, pesticides (organic or otherwise) won’t work on them. So, aside from digging them out of the vine as described above, there really aren’t any effective squash vine borer control methods to try.
The best way to control squash borers is to prevent them from infesting your plant in the first place. Here are some simple squash vine borer prevention methods you can try…
Kill Squash Vine Borer Eggs
Squash borer eggs are tiny, but they’re fairly easy to spot when you’re looking for them. The eggs are flat, oval shaped, and brown in color.
You’ll usually find them at the base of the stem of young plants, but they could be anywhere on the vines of mature plants. There could be just one egg, or a few in a small cluster.
You can simply scrap the eggs off into a bucket of soapy water, or wash the vines with organic insecticidal soap to kill them. Be sure to inspect your plants regularly, and remove any new eggs before they hatch.
Related Post: Natural Garden Pest Control Remedies And Recipes
Try Using Squash Borer Traps
The squash borer moth is attracted to yellow. So, try placing yellow sticky traps near your squash plants to trap the adult moths before they can lay eggs on your plants.
These types of traps are completely non-toxic and safe to use in the veggie garden. They can also capture other pest insects too, which is a double bonus!
Prevent The Squash Vine Borer With Aluminum Foil
Another great way to prevent squash borers is to wrap the stems of your squash plants in aluminum foil. This will confuse the moth, and prevent her from laying eggs on your plants. Here are the steps…
- Carefully dig down into the soil about 1/4″ inch around the base of the plant
- Cut a small strip of aluminum foil, and wrap it around the entire stem of each plant
- Push the soil back around the base of the plant, covering the bottom edge of the foil
- Check the aluminum foil regularly, and re-wrap it if necessary as the plants grow larger
Use Row Covers For Squash
Putting row covers over the top of young plants helps to keep the squash borer moth from laying her eggs in the first place. You can buy row covers that are made specifically for the garden, or you can make your own out of inexpensive tulle fabric.
Keep in mind that the row covers will also prevent pollinators from reaching your plants. So you can either hand pollinate your squash, or remove the row covers once the flowers start to open to allow for natural pollination.
Destroy Squash Vine Borer Pupae In The Fall
As I already mentioned, squash borers overwinter in their pupa stage, and they hibernate in the soil. So, there are a few things you can do in the fall the help get rid of squash vine borers…
- Remove and destroy all of your squash plants – especially any that have vine borer damage. Be sure to burn them or throw them into the trash, rather than putting them into your compost bin. Otherwise, the squash borers could just overwinter in there.
- Till or turn the soil in the fall to help prevent squash borers next year. This can destroy the cocoons, or expose them to hungry predators.
Grow Squash Vine Borer Resistant Plants
Well, sorta. Technically there is no such thing as a “squash borer resistant plant”. Unfortunately, all types of cucurbits are susceptible to the squash vine borer.
However, that being said, there are certain varieties that they prefer over others. They tend to really love zucchini (yellow and green), and hubbard squash the best. Some gardeners grow those varieties as trap crops to protect the less susceptible ones.
Squash Borer Control FAQs
In this section, I’m going to answer some of the most frequently asked questions about getting rid of squash vine borers. If you still have a question after reading through this post and these FAQs, then post it in the comments below. I’ll be sure to answer it asap.
Does neem oil kill squash vine borers?
Yes, it can kill the baby borers as they eat through the vine. But I do not recommend using neem oil for squash vine borers, because it’s not very effective, and it won’t work once they are inside of the vine. It can also be toxic to bees and other beneficial insects, so I don’t recommend using it on any flowering plants.
Will diatomaceous earth kill squash vine borers?
Yes. But it’s not very effective, and won’t work once they are protected inside of the vine. So I would not recommend using diatomaceous earth for squash vine borers.
Where can I find squash vine borers?
You can find them inside the stems, vines, or even the fruits. Look for the telltale signs listed in the section above called “Signs Of The Squash Borer”.
Getting rid of squash vine borers can take some work, but it’s worth it to save your plants, and have an awesome harvest. Plus, now that you know how to prevent squash borers organically, it will be so much easier! You’ll be able to enjoy growing squash in your garden again.
More About Organic Garden Pest Control
- How To Get Rid Of Cabbage Worms Organically
- Avoiding the Dreaded Iris Borer
- How To Get Rid Of Slugs In The Garden Naturally
- How To Control Flea Beetles In The Organic Garden
Share your method for getting rid of squash vine borers in your garden, or your best squash borer prevention tips in the comments below.