Tomato Hornworm

This big fat guy is a tomato hornworm.
I found him on my tomato plant. 

If left alone, he would strip the plant of all its leaves and munch on the tomatoes too.
They are hard to spot until the damage is done,
as they cling to the underside of the stem and blend into the foilage.
 

But I spotted them because of this.
A second hornworm is covered with the cocoons of the braconid wasp.
The wasp lays its eggs on the hornworm and the larva feed on the worm and then pupate in the white cocoons.

A third hornworm is also a parasite host.
As you can see, they aren't as big as the first guy and will die from the predation.
Braconid wasps are beneficial insects for the garden
allowing you to grow enough tomatoes for BLTs!