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The voracious tomato hornworm

 

The Tomato Hornworm is the larval stage of the Five-Spotted Hawkmoth (Manduca quinquemaculata). It is a large moth that you will see flying around the garden in search of a ‘landing pad’ on which to lay their eggs. That landing pad will become the depository of a cluster of light green to white eggs that will hatch in two to eight days, giving birth to many hungry babies.   At first, they are so small they are hard to detect with the naked eye, especially if you are older than 40. Their big appetites cause them to grow quickly, devouring the foliage of your prize tomato plants. If at any time you are inspecting your plants and you notice a cluster of eggs on the underside of the leaf, you will be doing great service by plucking that leaf and dropping it into a container with alcohol.   The alcohol will destroy the eggs and they will not hatch.

 

Tomato Hornworms have horns.   This horn is located on the rear end of the hornworm.   It is usually black and scary looking, something you don’t want to get poked by. There is a variety of moth that is similar, Manduca sexta, is a similar looking worm but its horn is red. 

 

So, what do you do when you have an infestation of these creatures?   One easy way to eradicate them is to use a foliar spray made with Baccillus thuringiensis

Bacteria, also known at Bt, with trade names being Dipel, Thuricide, Bactospeine, Leptox, Novabac. It is a naturally occurring soil bacterium that causes disease in insects. It is considered ideal for the garden as it has no toxicity to humans or bees. The interesting feature of this bacteria is that it produces crystalline bodies as part of its reproductive cycle. The worm or caterpillar ingests the leaf coated with Bt and the crystalline bodies grow inside the digestive tract and create havoc! It actually paralyzes the cells of their gut and it causes the caterpillar to stop feeding. Bt has been tested extensively on humans, birds, fish, bees, and other life forms. It shows to be lethal only to caterpillars thus making it an ideal pest control for your vegetable garden. I am having very good results using this product.

 

One of the easiest ways to use Bt is to acquire a hand held pressure sprayer with hand pump from your Garden Center.   Mix according to directions on the bottle.

Just about all garden centers carry this product. Be sure to coat the underside and top of the leaves. Bt will break down with UV light in about 4 hrs and it will also get washed away with rain. Be sure to apply often to control the caterpillar population.   It also works on Cabbage Looper caterpillars and any other caterpillar that would devour your crops. It targets only larval stage insects.

 

Another way to deal with the Hornworms is to pick them off and put them in a bird feeder or chicken coop!  Find them by looking for their dark colored poops also referred to as frass. Just look at the leaf above the frass and the worm should be there. The birds will love eating them as they are considered a treat.

To kill them outright, drop the worm into a container of alcohol. Alcohol dries out their outer covering and causes death.

 

There is no need to lose your crops to plant eating caterpillars or worms.   Bt to the rescue!   Its has been tested extensively since 1961 and has been proved to be safe for all creatures except the larval stage of insects. It will save time, prevent the gasps of surprise at discovering these munching insects, and the pea green spray of a squished caterpillar, ewwwww.

 

For more info: Cornell University, read Suzanne's Florida Gardening Articles