The Tomato Hornworm has plagued me for many seasons. He loves the things that I love; eggplants, peppers, tomatillos and tomatoes. If he existed on the pages of a Dr.Suess book, might think that he looked darling and colorful, but when I see him gnawing his way to the stalk on my tomato plants, all I can think is, “KILL, KILL, KILL!”
The Tomato Hornworm is the larvae of the hawk moth. They are the same color green as thefoliage on your tomato plant. They have diagonal white stripes with equally spaced small black spots on their sides. The adult moth is not harmful to your plants, but the larvae can be devastating. These colorful pests are found throughout the United States.
The damage they cause is easy to spot, although the larvae themselves are well camouflaged. They will begin eating your plant, normally at the highest point, and can defoliate
an entire plant in a few days. You can see their excrement, which are dark green in color, and up to ¼ an inch long.
The parasitic wasp is a natural eradicator of the TomatoHornworm. If you notice small white
sacks on the Tomato Hornworm, this is the parasitic wasp mentioned in our
previous blog. He will soon feed off the Tomato Hornworm, and rid your garden of this hungry pest. If you do not see any parasitic wasps ready to snack on your Tomato Hornworm, there are other measures that you can take. Although there are no known preventative measures that can be taken to ward off the Tomato Hornworm, there are some green methods of pest control to eradicate the Tomato Hornworm without harming your beneficial insects. If you see the Tomato Hornworm on your plant, remove him or cut the stem directly below the Hornworm and place him in a bowl of soapy water, if you can’t bear to smash him.
There is a Bacillus Thuringiensis variety, called Kurstaki, that you can use to kill the
Tomato Hornworm. It is also effective against cabbage worms, cut worms and corn ear worms. Basically, big fat vegetable plant eating moth larvae don’t like it.
You may also use a spinosad based product, which is a low toxicity biological insecticide. Spinosad is a new class of naturally produced metabolites from living organisms that provide excellent control of target pests, environmental compatibility, and low human risk. Both of these options should not damage your beneficial pest populations while still managing to rid your garden of the bad pests. The products should be ingested by the targeted bad pests and cause them
to die within a day or two. They are safe and effective, so you can administer the products yourself to rid your garden of unwanted eaters. [i]
[i] Good Bug Bad Bug, Jessica Walliser, 2008, St. Lynn’s Press