Lessons learned from run-in with disgusting borer

I should have known better.

The instant I saw one of my squash vines starting to wilt, I should have immediately identified the culprit. Instead, I assumed it just needed a bit more water on a hot day in the middle of dry spell. I now know this kind of thinking was proof yet again that gardeners are eternally optimistic even when faced with evidence that they shouldn’t be.

A day later it was clear that more water wasn’t what it needed. An invader was doing damage and I only need to look at the base of the vine to find him.

Finding squash vine borers is an odd mix of satisfaction at having identified the enemy along with disgust at seeing the writhing black-headed, white blob that could be the model for the main character of a B-movie.

I am particularly irritated that this hungry larva targeted my Sweet Jade kabocha squash, a new All-American Selections winner I was excited to try. It produced several fruits that will no longer have the opportunity to ripen.

The borer was quite large by the time I found it, but it had probably been working on devouring the squash plant from the inside out for a couple weeks. It hatched from an almost impossible-to-find egg laid by an orange and black moth. If I had not dispensed with it, there’s a good chance that would have completed its life cycle by burrowing into the soil and emerging next June or July to wreck havoc on next year’s squash plants.

It’s a garden problem where an ounce (or maybe a few ounces) of prevention would be better than an pound of cure.

Some prevention methods include a floating row cover to exclude moths, catching the moths as they rest on leaf bases at dawn and dusk, wiping the stems with a damp cloth every few days to remove eggs before they hatch or fertilizing heavily to promote rapid growth and offset injury by larvae.

I also could have buried nodes of the plant along the stem to promote rooting along the length of the stem to reduce injury should the larvae attack.

And I might have saved the plant if I had slit the stem open lengthwise and searched for larvae and removed them, then cover the stem with soil.

If there is good news, it’s that squash vine borers are less likely to attack some types of squash, including butternut, and I happen to have a lot of honeynut squashes — a close relative of butternut — planted right alongside the one that just succumbed to the evil, disgusting larvae invaders.

Planting marigolds, nasturtiums or radishes near squash plants may help a bit, but I regret to share that I had both marigolds and nasturtiums planted in this bed for this exact reason, and if it was successful in the past, it wasn’t this year.

I’ll plant my squash in a different bed next year, but moving them 10 feet away is unlikely to have much effect on this squash vine borer situation.

Vigilance and perhaps a little less optimism will be called for.