Asked June 25, 2019, 8:11 PM EDT

Hello, I am growing a grape mix of Texas green and California Concord and these little things have ABSOLUTELY destroyed my crops. How do I kill these filthy pests? I pruned my vines and I sprayed the removed vines with 409 Multi Cleaner and still NOTHING. They’re crawling about and breeding on top of my trash can. P.S. they sting if you touch them and they’re so tiny, they can be anywhere

Harris County Texas

8 Responses

Are they eating the fruit or the foliage? That appears to be a caterpillar so I'd suggest some sprays of B.t. every 3 or 4 days. I wouldn't use 409 any more on the grape plants.


I didn’t spray the plants. Just the pruned vines to see if it would hurt my plants. Didn’t kill a single caterpillar. They’re eating the foliage and bc of that the plant isn’t getting enough nutrients to produce fruit.

Okay, I'd spray the foliage with B.t. then. The sooner the better.

What is bt?

Bacillus thuringiensis, a naturally occuring bacteria that controls caterpillars but not other pests or beneficial insects. It is sold in many brand names depending on where you purchase your gardening products, so I just provide the ingredient name. A good garden center can point you right to the product as it is very common and popular due to the extremely low toxicity and lack of danger to beneficial insects.


Will this kill the caterpillars or just curb them from eating my plants? I’d prefer not to kill them bc they’re good eats for lizards that eat the bugs off my vines.

It will kill them. You'll have to decide whether the damage to your grapes outweighs the benefit of feeding lizards. I suspect the lizards have other food options.

I certainly hope so, guess today is the day for a good old fashioned murder