How to Get Rid of Catepillars in a Vegetable Garden
image by Photo by Flickr user net_efekt. http://www.flickr.com/photos/wheatfields/2934465697/
Caterpillars in your garden can be extremely frustrating. Your gorgeous plants may suddenly have leaves like Swiss cheese, covered in holes and taken over by munching caterpillars. It may be easiest to spray the plants with a synthetic pesticide, but those chemicals will also affect the many friendly bugs in your garden and end up on the vegetables you plan to eat. If you'd rather test some more ecologically sensitive options before taking that drastic step, this how-to will walk you through some alternatives, from handpicking caterpillars to trying a natural spray that can control the caterpillar invasion.
Hand-pick caterpillars from your plants as a first defense. You'll probably prefer wearing gloves for this. This approach works best if you have a small garden or are catching a caterpillar infestation at its earliest stages. Dropping the caterpillars into a container of water that has been mixed with a few drops of dish soap will kill the caterpillars, or you can collect them to feed to birds or chickens, who will love the treat. Hand-picking may be tedious, but it is the most ecologically sensitive method and can be extremely effective when done thoroughly.
Cover your garden with a specially designed crop-cover fabric. This approach is best used as a preventive measure; if you've had caterpillar problems in the past, you might choose to do this at the beginning of the garden season to avoid infestation. However, if you've been able to get the caterpillars under control through hand-picking, covering the garden with a special fabric that permits light and moisture through to the plants will decrease moths' access to your garden and their laying of eggs that hatch into caterpillars.
Add more friendly insects to your garden, such as purchased ladybugs or trichogramma wasps. Both of these insects are caterpillar predators and can help control the caterpillar population.
Use a natural deterrent spray, such as garlic spray, on your plants. A recipe is available in the Resources below. Caterpillars dislike the taste of garlic and will eat less of plants treated with this spray. Red pepper spray is another option.
Use a product like Dipel, which contains the Bacillus thuringiensis or "Bt" bacterium, as a last organic resort. Bt-containing products infect caterpillars and cause them to immediately stop eating your plants, then literally explode. However, Bt will not only infect your undesirable caterpillars, but also those that will eventually mature into butterflies and desirable insects, so if you value their presence in your garden, you should limit your use of Bt. Bt-containing products, however, are still preferable to using synthetic pesticides, which have a variety of negative side effects on soil, groundwater, animals, children and adults. See if a less damaging method can control your caterpillars first, then consider your other options carefully.