For years now I have done battle with the tomato hornworm. You know Hornworm: big, green brute with a spiky horn on his butt. Sort of a cross between a backward rhinoceros and The Hulk. He can get to be 4 inches long and will decimate a tomato plant overnight.
In the past I’ve used a number of methods to try to keep this marauder at bay.
• Sevin Powder: works pretty well but is a chemical insecticide.
• Neem oil: works pretty well and is a natural repellent, but has to be reapplied after every rainfall.
• Hand picking: It is harder than one might think to spot these well-camouflaged beasties. Even as big as they get, they can be hard to see in amongst the leaves. I look mostly for the leaf damage and poo-pellets they leave, then go hunting in that region.
• Braconid Wasp: a natural control in that these iridescent blue wasps lay their eggs on the hornworm and when the eggs hatch, they feed on the form and kill it. When I find a worm packing a load of eggs on its back I move that one to a sacrificial plant where it can live out its life and help proliferate the Braconids. I’ve never been stung by a Braconid despite having them nest in my barn eaves. I consider them good fellows and welcome them.
• Bacillus thuringiensis: a naturally occurring bacterium that attacks the digestive systems of numerous leaf-feeders, including hornworms. It is available in spray or powder form under the trade names of Dipel and Thuricide.
This year I tried a new weapon: Borage. Read More…
