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Cooperative Extension Service |
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Arbor Day
Dale Bumpers College
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Organic GardeningOrganic Insecticides • Traps and Physical Barriers • Organic Pesticides • Beneficial Insects • Preventing and Controlling Problems To spray or not to spray, that is the question. Pesticide usage is being questioned at all levels. They say there are two camps -- the nozzleheads and the foot-stompers (Those who spray, and those who don't). But it is more than that. It comes down to a personal decision on what you choose to do in your own yard. Can you live with some holes in your leaves, a few blemishes on your vegetables? How weed free does your yard need to be? Organic gardening is not a new concept, but it is an increasingly popular type of gardening. But organic means different things to different people. Some organic gardeners won't use any type of pesticide. (For the record, a pesticide is a product that kills pests. It may be organic or chemical in make-up.) So even spraying insecticidal soap is taboo. Others will only use animal or plant products, while still others practice sound gardening practices and spray as needed. Whatever type of gardening you are doing, and whatever you are growing, one of the most important steps, is frequent monitoring for problems. If you can catch a pest in its early stages, it is much easier to prevent a full-blown infestation. Identifying problems, and then identifying the culprit, is a major step to solving the problem. Many gardeners decide to go organic, deciding against any spraying. Then when their tomato plants are chopped off by cutworms, their corn is full of worms and their hosta leaves look like swiss cheese from nightly attacks by slugs, they reverse their decision, and pull out every chemical known to man to stop their problems. But there can be a happy medium. Sound gardening: building up the soil, watering, fertilizing and monitoring can help. When problems occur there are good, safe chemicals on the market, but if you choose not to use them, there are some good organic options as well. Insect control can be a challenge. There are numerous organic insecticides, physical barriers or traps, or beneficial insects. One option that is of limited use, is the hand-picking/foot stomping approach. It always amazes me when I see a gardening show from up north, advise gardeners not to worry about bugs, when you see one, just pick it off and kill it. That may work fine in the north where there are a few bugs per year, but in Arkansas that may turn into a full time job during an average growing season. Again monitoring for problems is crucial. There are several good baits or traps on the market to help you determine the number of pests you have. Hanging phermone traps in your fruit trees, can help you determine when you need to spray. Hanging bright yellow sticky traps near gardenias or hibiscus can trap white flies. Shallow trays of beer strategically placed where slugs are a problem can attract slugs, where they fall in the beer and drown. Physical barriers have some potential. If worms are eating up the cabbage or into your greens, you can protect the plants using floating row covers made of spunbonded fabric. It allows for air-circulation, but keeps the pests out. This will work for many plants, but if you need insects for pollination, it won't work. Using a collar around your tomatoes or a band of aluminum foil will prevent cutworms from cutting off your plants. A sharp mulch such as sweet gum balls can keep soft-bodied slugs away from inviting plants. A drop or two of mineral oil applied weekly when the silks appear until they turn brown on your corn, can prevent corn ear worms. There are also many organic pesticides on the market with more coming all the time. But just because it is "organic" does not mean it is totally safe. Some organic compounds can be hazardous -- consider nicotine sulfate which can be harmful to you as well as the insects, and rotenone, a good organic spray, but keep it away from fish ponds, because it can kill fish, and others can kill beneficial insects along with the bad ones. When choosing organic sprays or any type, make sure you know what you are trying to kill, before choosing a spray. One of the best organic insecticides is BT or bacillus thuringiensis. There are several different formulations, each targeted for specific pests. The most common one is for caterpillars. Caterpillars ingest leaves sprayed with this compound and it will act as a stomach poison and kill them. It won't hurt you or other insects, so don't use this product if you are trying to kill aphids. Insecticidal soap works well as a contact spray for soft bodied insects. Diatomaceous earth works on soft bodied insects and slugs. Rotenone is a plant-derived insecticide which will control a wide range of insects. Sabadilla dust is a product made from ground seeds from a South American plant. It controls grasshoppers, beetles and caterpillars but can also be harmful to honeybees. Horticultural oils or refined oils don't contain insecticidal properties but work by smothering out insects and can be very effective on scale or overwintering insects. As with any pesticide, always read and follow the label directions. Another option, and one that is somewhat newer, is beneficial insects. There are many people out there who think the only good bug is a dead bug. We all know about honeybees and lady bugs, but there are numerous good bugs out there, and you will want to encourage them. Many occur naturally in your garden and can monitor and contain pest problems. Catalogs are available where you can purchase these beneficial insects, but make sure you need them before you order. Many have specific food or insect needs. Ladybugs are great aphid hunters. You can incorporate all the ladybugs in the world, but unless you have aphids, they won't stay in your garden, they'll move on to find some food. Ladybugs, everyone can identify, or so they think. But the larval stage of a ladybug is every bit as desirable as the red-spotted adult, yet they look nothing like a mature ladybug. The larvae look like tiny black alligators with orange or blue spots on the back which is covered in spines. Both are useful if aphids are a problem. Lacewings larvae are another great aphid eater, and their larvae look similar to ladybugs, except they are brown in color. Dragonflies which skim about over ponds or near water, should be left alone. They eat mosquitoes and gnats. Ground beetles are good insects and feed at night on cutworms, slugs and other soil insects. Parasitic wasps are also beneficial and include braconid wasps which attack aphids, caterpillars and the larvae of many beetles. Ichneumonid wasps can help to control whiteflies, aphids and some caterpillars. Praying mantis have been seen as a beneficial insect, but don't run out and buy hundreds of them. They do eat insects, but they aren't picky. They'll eat anything in their path, including each other. If you find some naturally occurring in your yard, enjoy them, but don't buy them to save your plants from insects. Something newer as a source of beneficial insects are beneficial nematodes. Data is somewhat iffy as to effectiveness. Timing can be very important. They also won't tolerate dry soils. But they are an option for soil born insects. Preventing and Controlling Problems Controlling insect pests can be a problem, whether it is in your lawn or flowers, fruits or vegetables. Monitor frequently for problems and control them as soon as they are spotted. But, also, practice sound gardening practices. Water regularly, fertilize, mulch your plants. Hoe to keep weeds out and harvest fruits and vegetables as they get ripe. Overripe fruits and vegetables can invite insects. Weeds can be a temporary residence for insects and stressed plants are an invitation for problems. A well-maintained, healthy garden will be more resistant to problems. Regardless of how diligent you are, there will be insects in your garden. Before you kill it, make sure it is causing harm. If it is, control it early before it builds up to harmful proportions. |
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