Are your squash plants wilting and dying for no apparent reason?? Yeah. There is an apparent reason for that. The dreaded squash vine borer. Here’s how to get rid of it and save your squash plant from imminent death.
I was away from my garden for approximately 2 days. In that time there was rain. Actual, falling from the sky, RAIN. We haven’t had a lot of that this summer. I love my watering system but there is nothing like genuine rain.
City water is filled with chlorine, fluoride and a bunch of other stuff I didn’t bother to look up for the same reasons I don’t look up the calories in a Big Mac. Nobody needs that information if they want to continue to enjoy life.
Watering my garden with city water keeps it alive and growing. But having my garden watered by rain is like watering it with magic cloud happy tears (comprised of equal parts steroids, Miracle Grow and genuine miracle).
The biggest growth from the rain happened in my squash beds. But if I hadn’t checked them for Squash Vine borer a couple of weeks earlier I may not have had any squash vines to grow.
What are Squash Vine Borers?
Squash Vine borers are disgusting, white, maggoty creatures that burrow into the stem of squash vines. The pests overwinter in the soil and when the time is right in the spring they emerge and proceed to lay eggs on their favourite plants; squash, zucchini and pumpkins.
The eggs are laid on the stem of the plant and when they hatch, the squash borer eats its way into the squash stem, just above the soil line.
Once inside the stem, the squash vine borer continues to eat the inside of the stem hollowing it out until the plant eventually wilts and dies a surprisingly rapid death.
Identifying Squash Vine Borer Damage
In the mess and tangle of squash vines, it’s easy for vine borer damage to go unnoticed, so you have to make a point of looking for signs around the end of June and beginning of July.
Signs of squash vine borer activity are:
- Mushy main stem that feels hollow when you squeeze it, instead of firm.
- Holes or cracks in the stems of the squash plant, near the soil line.
- Evidence of yellow fluffy frass (squash vine borer poop) around the soil line and on the stem. It looks kind of like sawdust.
You can see the 3 spots on this one large squash vine that vine borers have gotten into it. Anything circled is a vine borer hole. Anything highlighted slightly in red is where the vine will die. Basically it’ll die from the point of the hole straight out.
Since vine borers make their entry points at the start of the squash vine where it meets the soil that basically means the entire vine from that point out will die taking all the potential squash with it.
So what do you do?
You have to cut those suckers out. You have to lance the wound.
Just because you can’t see the vine borer hole doesn’t mean you don’t have them. They’re often on the underside of the stem so there’s no visible evidence of a hole.
In that case look around the soil for orangey gunk. That’s squash vine borer frass (poop). If you see it. You have squash vine borers.
And again, the easiest way to check for vine borers is to squeeze the stem near the soil line. If the stem feels hollow, you have a vine borer.
Yup. That’s just how gross they are. So to reiterate:
How to Get Rid of Squash Vine Borers
- Look for evidence of wilted leaves or stems. If you have them chances are you have squash vine borer.
- Check all around the stems of each plant for holes or frass (orangey poop)
- Feel the stems near the soil. They should be firm not soft.
- Slice into the stem with a knife where it is hollow and look for the vine borer. Extract it.
- If you can’t see the vine borer, scrape your knife back and forth inside the vine until you’re sure nothing could have survived. You’re trying to squish/kill the vine borer inside the vine.
- Cover open wound of stem with soil.
- Check your vines even if your vines aren’t wilting. Catching the borers early is key to success.
- While your plant is growing earlier in the season, push your vines towards the soil and hold them in place with a mound of soil on top, or a U pin. This will allow the vine to root there, helping that portion of the vine survive a vine borer attack at the main stem.
- Grow vine borer resistant varieties of squash. Butternut and Honeynut are two that seem to be less vulnerable to vine borers.
Preventing Squash Vine Borer Damage
- Grow borer resistant varieties of squash like Butternut or Honeynut.
- Clean up all of your squash vines as soon as you pick your squash.
- Rotate zucchini, pumpkin and squash beds. The cocoons overwinter in the soil so moving to a new location should help eliminate chances of them being born right next to your plants.
- If you plant in a bed that you’re fairly confident doesn’t contain any cocoons you can cover your squash plants with row cover. This will prevent the Squash vine borer moth (Melitta curcurbitae) from laying eggs on the stems.
- Mound soil or mulch up high around the stem of your vine as it grows to prevent a moth from laying eggs there.
- Wrap the main stem with tin foil, a plastic bottle or anything else to cover up the stem and keep it safe from a moth laying eggs. (I personally find this method to be a bit iffy, but others swear by it)
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