04/08/2026
The caterpillar on your tomato plant is covered in tiny white things and you're about to pull it off and throw it in the trash.
Stop. Those white things are saving your garden.
The caterpillar is a Tomato Hornworm — 4 inches long, fat, bright green, eating your tomato plant at a rate of one full branch per day. You hate it. Understandable. She's consumed $15 of tomato production since Tuesday.
The white things on her back are cocoons. Each one is a tiny silk case containing a developing Braconid Wasp — a parasitoid so small you've never noticed one, so effective that she's the single best biological control for the single worst pest in your vegetable garden.
Here's what happened. Two weeks ago, a female Braconid Wasp landed on this hornworm and injected 50 to 80 eggs beneath the skin using an ovipositor thinner than a human hair. The hornworm didn't notice. The eggs hatched inside the caterpillar's body. The larvae fed on the hornworm's non-essential tissues — fat reserves, hemolymph, muscle — carefully avoiding the organs that keep it alive. The caterpillar continued eating your tomatoes while being consumed from the inside.
Three days ago the larvae chewed through the skin, emerged onto the surface, and each one spun a white silk cocoon on the hornworm's back. There are 60 of them. They look like grains of rice glued to a green sausage. Inside each cocoon, a wasp is pupating.
The moment the cocoons appeared, the hornworm stopped eating. Completely. She hasn't taken a bite in 3 days. She's not dead — she's standing guard. The parasites have hijacked her behavior. She sits on the stem, motionless, shielding the cocoons with her body. She's become a living nursery for the wasps that are killing her.
In 5 to 7 days, 60 adult Braconid Wasps will emerge from those cocoons. Each one will find another hornworm and inject another 50 to 80 eggs. One parasitized caterpillar produces enough wasps to eliminate every hornworm on every tomato plant in your yard within 2 weeks.
The caterpillar with the white cocoons is not a problem. She IS the solution. She's already stopped eating. She's already done. Removing her removes the 60 wasps that would have protected your garden for the rest of the season.
If you see a hornworm with white rice on its back — put down the gloves. She's already been handled.