Green Solutions to Garden Pests

Oh no! My organic garden is being consumed by organic bugs! Now what do I do?

Green is definitely the color of the decade, and more and more gardeners are turning to organic gardening principles for their landscapes and kitchen gardens. But what do you do when the hordes attack? Just because your harvest is in danger of premature consumption, doesn’t mean you have to abandon all your “green” principles. You are not defenseless!

Before reaching for the sprayer, consider all aspects of the problem. Chemicals, even organic ones, are only one weapon in your arsenal.

Begin with proper plant choice. Some plant varieties resist insects or diseases better than others. For example, many crabapple varieties are resistant to a bacterial disease called fireblight, while most modern roses repel fungal diseases such as black spot, powdery mildew and rust. Vegetables varieties may be described as being resistant to a particular disease (they won’t get the disease) or tolerant (they get the disease but produce a crop anyway). When choosing plants for your yard, ask about the disease resistance of the variety you are considering.

Some problems may be resolved with a change in gardening practices. Healthy plants naturally resist pests and diseases. In fact, almost all local turf grass problems result from improper care of the lawn. (CSU Extension’s Fact Sheet 7.202 explains how to grow a great lawn.)

Preventing problems is much easier than eradicating a pest. Instead of spraying an herbicide to kill your weeds, keep them from sprouting with three to four inches of mulch combined with a pre-emergent weed killer (one type is derived from corn). Many plant diseases overwinter in the soil. Mulching around your plants creates a physical barrier preventing disease-contaminated dirt from splashing up onto the leaves. Physical barriers are also effective against any critter that wants to eat your garden. Row covers made from spun polyester may not be attractive enough for your front yard, but they are extremely effective at excluding insect pests such as cabbage moths, leaf miners, flea beetles, and grasshoppers.

If you do have problems, you can keep them from spreading without resorting to sprays. Cleaning up diseased leaves in the fall and disposing of them in the trash will prevent spores from surviving to the next growing season. Disinfect pruning shears between cuts by dipping them in a solution of 1 part bleach to 9 parts water. Remove fatally afflicted plants before they infect their neighbors.

Often, insect pests don’t need controlling at all. For instance, trees that are about to lose their leaves in the fall won’t be damaged by an insect chewing on those leaves. Is it worth spraying a $2 annual with $10 worth of insecticide? A population explosion of aphids will attract ladybugs and lacewings, which may control the outbreak on their own. Learn to tolerate a few bugs among the leaves. Give nature a chance, and practice patience.

Sometimes, the only way to solve a major problem is to spray. Pesticides are chemicals (natural or man-made) used to kill insects and other invertebrates, weeds, or to treat various plant diseases. Herbicides, fungicides, and insecticides are just some types of pesticides. In most cases, there are plenty of options to choose from in each category. Keep in mind that some man-made chemicals actually have less of an impact on the environment than some natural ones. The goal is to use the least toxic chemical that will still be effective. Check with the master garden helpdesk for advice relating to your specific problem.

Contributed by Leslie Holzmann, Colorado Master Gardener. For answers to your horticultural questions, contact the Master Gardener Help Desk at 520-7684 or CSUmg2@elpasoco.com.