The garden is in full swing, and that means so are the pests. I've been asked by a number of people what this pest is, it's the tomato horn worm. This pest has a high yuck factor. It can be anywhere from 2" to 4" long. It's pretty gross. It will hold on tight to the tomato plant and can be tough to get off. I encountered one at a garden i work for and actually cut off a little piece of the plant to get it off! Usually you can pick them off (wear gloves, it's a bit gross) and put them in a bucket of soapy water to kill them. You want to get them off the plant as they are voracious. They will eat the leaves and start on the fruit as soon as they come out. Picking them off is really the only good organic measure to control these insects. The adults are large moths, they lay their eggs on the underside of leaves. It's always a good idea to check under the leaves of your plants for eggs, as most pest insects do lay their eggs there. Cultivate the soil deeply in the fall to disturb the pupae of these insects because that's where they over winter. There is one instance in which you don't want to get these pests off your tomato plant.

If the tomato horn worm looks like this, you want to let it be. The reason is this insect is already dead. It's being parasitized by a trichogramma wasp. These are tiny wasps and they won't sting you, but they will kill tomato horn worms. The wasps lay their eggs inside the worm, they hatch and eat the insect. So when you see a tomato horn worm that looks like this, it's already dead, the wasp larvae have eaten it and it won't do any more damage to your plant. What you see on the outside of the worm are the pupae  in their cocoons before they hatch into adult wasps. Obviously you want more of these beneficial insects in your garden to take care of any other tomato horn worms they might encounter.