Top 10 Organic Pest Controls

No matter how good a gardener you are, at some point or another animals, insects, and diseases will attack your plants. Organic gardeners know this is a fact of nature and will tolerate some damage to their fruit trees, berry bushes, vegetables, and herbs. A perfect plant doesn't mean one that is completely blemish-free. However, if left unchecked, a little damage can quickly turn into a lost crop.

There are a number of organic pest control techniques you can use to keep your plants safe and pests at bay.

NOTE: One of the main tenets of the USDA certified organic program is “continuous improvement,” which means that organic’s strict regulations are routinely updated to protect environmental and human health. As a home gardener, if you’re interested in following the most current organic standards, contact the MOSES organic hotline for recommendations based on the specifics of your situation.

1. Choose the right varieties

The best way to prevent insect and disease attacks is to select the right variety of tree, shrub, or vegetable for your climate and planting site. A disease-resistant apple tree, such as 'Liberty', will require much less spraying than susceptible varieties. A blight-resistant cucumber variety, such as 'County Fair', will make controlling disease much easier.

2. Add floating row covers

Nothing stops insects like a physical barrier, and one of the best for vegetable crops is the floating row cover. This lightweight, nonwoven fabric lets in light, air, and water but stop insects from feeding and laying eggs. Row covers work great on greens, broccoli, root crops, and any crop that doesn't need pollination by bees. They will also protect seedlings from cold temperatures down to 28°F or lower, depending on the thickness of the fabric.

3. Install an electric fence

Speaking of barriers, an electric fence is one of the only sure ways to keep Bambi, Rocky Raccoon, and other animals from your prized edible patch. While repellent sprays may work for a while, animals are smart enough to get used to the spray and move in anyway. If deer pressure is low, use a single strand of electric fence wire 30 inches off the ground. In regions with large populations of hungry deer, use multiple strands, spaced a few feet apart. The key is to set up the fence early in the season, before animals find your vegetable patch or fruit trees. You can "teach" the animals to avoid the fence by baiting it with peanut butter. After a few harmless shocks, they will probably avoid the area all together.

4. Try Bacillus thuriengensis (Bt)

This essential organic pesticide is a naturally occurring bacteria that attacks the larvae of butterflies and moths, including cabbageworms, tent caterpillars, corn earworms, hornworms, and cutworms. The beauty of this popular control is that it only attacks caterpillars in the Lepidoptera family and doesn't harm other insects, bees, pets, and humans. The downside is that all butterfly and moth larvae are susceptible to this pesticide, so use it sparingly and avoid it on butterfly larva plants, such as parsley. There are also strains of Bt that attack Colorado potato beetle larvae (Bt 'San Diego') and mosquito larvae (Bt israelensis).

5. Use horticultural oil

Unlike its heavier and more toxic cousin, dormant oil, horticultural oil is a lightweight, fine-grade petroleum- or vegetable-based oil that coats insect eggs, larvae, and adults and smothers them without harming foliage. Use oil in the vegetable garden to kill aphids, leafhoppers, spider mites, and whiteflies. A few drops of oil in the tips of developing sweet corn ears will control corn earworm. Oils present few risks to both gardeners and desirable species and integrate well with natural biological controls. They also dissipate quickly through evaporation, leaving little residue. However, oils can damage plants if applied at excessive rates, on sensitive plants, or on particularly hot (above 100°F) or cold (below 40°F) days.

6. Wash plants with insecticidal soap

This fatty acid-based product is one of the safest sprays to use in the garden. It primarily kills soft-bodied insects, such as aphids, mealybugs, and whiteflies. Commercially formulated insecticidal soaps are better than home remedies because they have been tested to be safe on a variety of plants. However, some plants, such as peas, can be burned by the spray.

7. Get rid of slugs with iron phosphate

Slugs and snails love cool, moist weather and dark hiding places and can make a dinner out of your leafy greens. The best methods of control include spacing plants generously so the soil dries quickly and removing mulch where these pests like to hide. Copper wire barriers will keep slugs out of containers and raised beds. One of my favorite products is iron phosphate-based pelleted bait, which I sprinkle in the garden. The pellets have a slug attractant mixed in. When the slugs and snails come to eat the bait, the iron phosphate proves fatal, killing the slimy critters without harming other beneficial insects, animals, and humans.

8. Use neem oil

This extract from the seeds of the tropical neem tree is nontoxic to pets and humans, but helps control some of our worst pests, such as Japanese beetles. Instead of killing the adults outright, it acts as a deterrent, stopping insects from eating and mating.

9. Spray with spinosad

This soil-dwelling organism was discovered as a by-product of the rum processing industry in Jamaica. A fast-acting bacterium, it kills a range of chewing insects such as caterpillars, thrips, sawflies, leaf beetles, spider mites, and leaf miners. It's not as effective on sucking insects. Although spinosad shows low to moderate toxicity for most beneficial insects, it is toxic to bees. Be sure to spray only in early morning or late evening when bees are not flying to avoid harming these pollinators.

10. Set traps

Fruit trees are notorious for having insect pests that attack the developing fruit. There are two types of traps: one type, such as the apple maggot trap, controls the pest, while the codling moth trap is an example of another type of trap and is used to monitor insect populations so you know when to spray. Some traps attract the insects by color and form, such as the yellow sticky cards used to trap whiteflies. Other traps attract the insect with a pheromone lure. Check out fruit tree supply stores for the best traps for the pests in your area.

Information courtesy of the National Gardening Association,