Protect With Row Covers
There’s a sinking feeling that comes when you spot the first cabbage moth hovering over your garden. Traditional gardeners use some of the worst chemical sprays to control them. And that doesn’t always work, especially as the larvae eating your plants mature. (Personally, I’d rather eat worms than pesticides.) Organic gardeners hunt for egg clusters on the underside of leaves and smash them, pluck the worms that they find and even snatch the egg-laying moths right out of the air (okay, I was successful doing that once). Other natural solutions include using Bacillus thuringiensis (Bt) a bacteria that attacks certain larvae. Or you can try Neem oil, which works on a variety of pests and fungal problems.
One of the easiest methods to protect row crops from invading moths, other flying insects and larger, four-legged pests is the floating cover. Row covers are made of different materials and come in different weights but the idea is simple: they shelter tender row crops from garden pests. They are laid over plants without further support — thus the “floating” — but allow sunlight — as high as 85% or more — and moisture to penetrate. They also help to retain heat, a plus in cooler climates, and protect against wind damage. Best is the fact that they shield your plants from egg-laying moths and other flying insects, including those that spread disease. They’re good protection from cabbage moths, looper caterpillars, flea beetles (that like radishes and eggplant, among others), cucumber beetles, Army worms, grasshoppers and even rabbits and birds (think strawberries). For a full list of pests that floating covers discourage and suggestions for both home and small commercial use, see this article from the University of Kentucky Extension Service (PDF). Here’s a video about using row covers from Michigan State University which includes an interesting tip about controlling slugs under row covers (caffeinate them).
Floating covers should be installed as soon as plants are able to support them. They can be anchored with dirt, stones or lengths of rebar. Remember to provide plenty of room for the plant to grow. Don’t think for a moment you can cover your plants and forget them. You’ll need to lift your covers occasionally to check for weeds (hint: mulching around your plants will help keep weeds down). Remember that insect or eggs that over over-wintered in the soil from previous infestation might be released UNDER your cover. If you’ve had trouble in the past, you’ll want to be even more diligent about checking beneath your cover for problems. And if you’re covering plants that need pollination — tomatoes, cucumbers, squash, eggplant and the like — you’ll need to make sure that you make time for this to happen (or pollinate by hand). But mostly floating covers will do a lot of the plant care for you. For more discussion of covers go here.