It's Donna, the prodigal Master Gardener, returned to share a bit about my recent discoveries regarding the dreaded and devastating squash vine borer. My apologies for being gone for so long - sometimes life just gets in the way of things...This year my garden is back in full-swing as are, unfortunately, the squash vine borers.
Here's a squash vine. Looks pretty healthy, yes?
Look again, see anything funny? (here's a hint)
Dead Snails Leave No Trails: Natural Pest Control for Home and Garden. Isn't that a great name for a book?
Some of you with long memories may recall from past posts of mine that I'm a big fan of manual control of pests (Cabbage worms, Squash bugs). So naturally the idea of 'search and destroy' excited me. I set out to do just that over the course of a couple of days, and I routinely found the eggs as you see above. While they are quite small and easy to miss (as you'll see momentarily), they are easy to pick off (I'm actually collecting them in a small jar, though I really don't know what for...) I was very excited, thinking, 'NOW I'VE GOT YOU ALL!!!!! I'm cutting you off at the source! BWAHAHAHAHAHAHAHAHAHA!' Ahem.
I proceeded to rest on my laurels as I began to enjoy a bumper zucchini crop. But then, a couple of days ago I started to notice that ever-familiar sawdust-lookin' stuff called 'frass' coming out of some of my vines. I was in disbelief, how could I have worms? I was so careful!!!
So, I embarked on 'Plan B' of 'Save my Zucchini' - search and destroy the worms themselves. I was so bummed that I had to resort to what I like to call 'precision surgery' - carefully inserting a knife into the wounds and 'coaxing' out the worm. Or at least jabbing or slicing it 'in situ'.
Hey look, here's one now:
This is, er, was actually still a fairly small worm. They can get about twice this size if you don't catch them first. And if you don't catch them soon enough, here's what can happen:
I regret to say that I've lost a couple of my zucchini plants after all, and may lose more. But through this experience I learned a couple of very important points that I want to share with you, to help you in your own quest to 'search and destroy'.
First, I always thought that since I saw the frass on the main stem of the plant, that the eggs were deposited on that main stem. What I'm finding this year is that, as in the first photo above, the eggs are usually laid on a leaf stem (not far from the main stem). This was a surprise to me, but it made it easier to find and pick off the eggs. What the worms do, apparently, is make their way down the hollow leaf stem to the main stem. So when you're looking for worms, look for damaged leaf stems. You might see holes or slits in them, with browning around the edge. If you can find the worm before it gets to the main stem you just headed off a LOT of damage. Just cut off the stem at the base.
Second, eggs can also be laid on flower stems. Check this guy out:
Third, the book I referred to above indicates that the plant MAY be able to be saved if the damage isn't too severe. Mound up soil around the damaged vine, and (according to the book), the stem will begin to grow new roots. I'm not sure if my vines are too far gone at this point, but I figure it can't hurt.