Squash Vine Borers

Over the past week or so, we suddenly lost all but two of our yellow squash, three zucchini plants, several pumpkins and one butternut squash.  They would be beautiful and lush one day, wilted the next and gone within another day.

Melittia cucurbitae foraging holly blossoms. Georgetown County, SC

At first we thought it might be squash bugs or cucumber beetles spreading bacterial wilt, but I had sprayed them with a Neem Oil solution and the pattern didn’t quite follow that of the cucumbers we lost to wilt.  Next, I thought it might be the heat.  We have had one round of excessive heat warnings after another and are currently under one until this weekend.  I put out improvised water globes made from 2 liter bottles near water hungry plants.  They still wilted.  Then after a bit of research I came across the Squash Vine Borer.  This new threat, is the larvae of the Melittia curcurbitae, a type of moth resembling a wasp.  They lay their eggs in the stems of vining plants such as summer squash, winter squash and pumpkins.    The larvae feed off the center of the stems, effectively cutting off the flow to the rest of the plant, hence the wilting symptoms I saw.  Damage from vine borers is noticable by green or orange frass (excrement) that closely resembles sawdust around splits in the vine stem or leaf stems.  Our poor squash had textbook symptoms.

This morning I extracted the larvae by using a sharp paring knife to gently cut vertically along the slits where I saw frass, until I found the larvae.  Then I pried them out (several had multiple larvae) and tried to smash them into little bits as a punishment for obliterating so many of my plants.

Squash Vine Borer

Squash Vine Borer

Vine Borer Frass

Squash Vine Borer Frass


Vine Damage

Summer, our Welsummer hen, got in on the fun by eating the bugs and hunting around for more.  She even got to a couple before I did!  Once she’d figured out what I was doing, she followed me from plant to plant, waiting expectantly for treats.  At least someone enjoyed our chore for the morning.

Hopefully the remaining plants did not sustain too much damage to recover.  We shall just have to wait and see what happens.


Summer looking for more treats

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