Thursday, 16 October 2008

Don't Kill That Bug!

Hello, Marc from GardenDesk here.

In my organic vegetable garden I sometimes have to tolerate minor pest infestations. The only insect control I employ is hand-picking and destroying the problem insect. Many people reach for an insect killing spray at the first sign of bugs on their plants.

That is the wrong approach. Never mind what that does to the environment and your health, poisons don't discriminate. When a gardener applies an insecticide, there are actually "good bugs" in the garden that are killed along with the problem insects. If you are new to the idea of beneficial insects, let me explain. If you saw the bug in the picture on one of your tomatoes, would you want to destroy it?

You shouldn't. That is a Spined Soldier Bug and he is a soldier in the gardener's army. The Soldier is beneficial because it eats armyworms, beetles and cabbage loopers. The Soldier Beetle is so beneficial that there was a big article in Organic Gardening Magazine about how to trap them in the wild for the purpose of releasing them in your garden. Read the article HERE.

Here is a picture of another insect you might find in an organic vegetable garden:

Surely that ugly thing needs to be killed, you might be thinking. There is more in this picture than meets the eye. This insect is a very destructive Tomato Hornworm, but look closer. What about the little white cocoons attached to it? These are Braconid wasp cocoons. Braconid Wasps are parasitic. They live in the Hornworm (which is actually a caterpillar) as larvae, and then make cocoons on the outside to pupate. The adult wasps emerge, kill the caterpillar and fly off to find more caterpillars to destroy.

See, who needs chemical insecticides to control caterpillars?

To further illustrate this cycle, my daughter actually kept a hornworm in a jar and fed it tomato leaves. We got to witness the tiny wasps emerge and kill the hornworm. here is a picture montage lifted from one of my older posts about this:

We emptied the whole jar back out in the garden. I counted over 300 cocoons on this hornworm! If only half of them find a new caterpillar to invade, I soon won't have any caterpillar problems at all. No need for chemicals - nature can take care of things if we let it.

There are even smaller parasitic wasps out there. GardensAlive! is a store that sells organic and natural fertilizers and pesticides. They sell Trichogramma wasps for you to introduce into your garden to do a similar thing that my Braconids are doing. The Trichogramma wasps are almost microscopic!

These are just a few examples of beneficial insects. Depending on where you live, you will encounter different ones. When you find an insect in your garden, you should do some local research to determine if it is good or bad. If there is plant damage near by, don't assume that the creature you found is the culprit. It might be there to feed on the actual pest!

Other beneficial insects that I have discovered in my garden are ladybugs, lacewings, mantids and bees.

The bottom line is this: If you spray insecticide at all, you won't have any beneficial insects to help you. When the pest insects come back, they will inflict even more damage because of the absence of beneficials.

Gardeners and farmers who use chemicals force themselves into a never-ending cycle. They continue to have to spend money to temporarily solve their pest problems in an unsafe and harmful way. I think nature's way is better. Sometimes I may have to wait on the beneficials, hand pick pest bugs, and even lose a few crops, but I like watching nature work. It keeps gardening a fascinating endeavor instead of a divide and conquer campaign. Knowing that I'm participating with nature instead of destroying it makes makes me feel good.

Keep Growing!-Marc