Garden Pests: Grapevine Moth Caterpillar

I’ve learned that it’s a good habit to walk around the garden every day or two to examine all of your plants up close. Pest and disease problems seem to spring up over night, and the earlier you catch them, the better your chances of saving the harvest.

Today, as I walked around the yard looking things over, I noticed something going on with my grape vines that I didn’t like the looks of.


In my leaves.

grapevine moth larvae
A closer look revealed the culprit. Little tiny larvae of something.

I immediately grabbed my pruning shears and a bucket, and set to work clipping and removing all of the leaves that had larvae or any evidence of them. It’s important to collect the leaves in a container and dispose of them properly (ie: the burn barrel), or else the larvae will just grow, multiply, and return to your plants.

Dutifully, I went through all of the vines, lifting leaves and examining the undersides, trying to find as many pests as possible. And then I came across this guy…

grapevine caterpillar
Unless there’s another grape-eating caterpillar that looks very similar, I believe this is a European Grapevine Moth Caterpillar.

They’re a relatively new pest in the US, first spotted in California in 2009.

I looked it up, and found this alarming information:

In May and June, first-generation larvae web and feed on the flower clusters. Second-generation larvae (July-August) feed on green berries. Young larvae penetrate the berry and hollow them out, leaving the skin and seeds. Third-generation larvae (August-September) cause the greatest damage by webbing and feeding inside berries and within bunches, which become contaminated with frass (excrement).

~ Source

This is so not good. We’ve never had these caterpillars before. In the past, our main grapevine pest has been June Bugs (Japanese Beatles), but at least they only eat the leaves of the vines and leave the fruit alone. From the sound of it, grapevine caterpillars decimate the entire plant.

After doing a little more reading, I’ve learned that supposedly Stink Bugs (aka Shield Bugs) are predators to the Grapevine Moth Caterpillar larvae, and lucky for us- we’re infested with Stink Bugs! I’ve instructed the kids to put as many as they can catch on the grapevines. In the meantime, I’ll be hand picking any and all damaged leaves and baby caterpillars that I can find on my vines.

I’ve also read that BT (Bacillus thuringiensis, a completely natural bacterial) will kill the larvae as well.

Wish me luck.

Have any of you ever dealt with Grapevine Moth Caterpillars? What have you found to work best for you?

5 thoughts on “Garden Pests: Grapevine Moth Caterpillar”

  1. I live in the south west desert outside of las vegas. As the temperature rises, do the caterpillars go away? I’m not seeing the damage I saw even a couple of weeks ago. It’s 9am and 100 degrees. Or did my BT spraying actually get them all?

  2. Kendra,
    You are right. Though I have not had the caterpillars on my grapes. I have had the tomatoes horn worms on my jalapenos. I am usually content to hand pick them. But one time I picked so many on my plant that I decided to BT just in case I missed any.

    Wow! what a job it did. By the next morning there must have been 20 lifeless blackened pests hanging from the plant.

  3. BT works wonderfully on all little caterpillars. I use it on Zucchini, Tomatoes, Cucumbers and Green Beans in my garden. Make sure you get to the underside of the leaves with the spray. Also adding some Diatomaceous Earth around the base of the plants will help with cutworms. Sometimes it is so ironic how much we kill trying to grow something else….jeez..


Leave a Comment