Backyard Gardener: Spinosad for natural pest control

Hello Mid-Ohio Valley farmers and gardeners. Happy 4th of July. I talk to concerned gardeners every year about insects and disease, so this week I will discuss using a more natural approach with the insecticide Spinosad, which can be used for organic production under the product name Conserve.

Integrated Pest Management is extremely important to fruit and vegetable production. The ongoing battle against insects and disease in our gardens and farms employs many management strategies including resistant varieties, hot-water seed treatment, rotation, water management, trap crops, natural and biological controls, sanitation and prevention, mechanical and cultural controls, action thresholds, selective materials and resistance management. As a last resort, we target tough to control pests with selective and carefully measured use of chemical pesticides.

Gardeners and farmers are looking for a product that is safe, effective, and does not leave toxic chemical residues. Many home gardeners have been using Sevin (carbaryl) for years (should I say decades?) for insect problems. Due to overuse, many insects are now resistant.

As an Agriculture Extension Agent, I receive many calls about insect damage on horticulture crops. Cabbage worms, corn ear worm, and Colorado Potato Beetle can be devastating to a crop. Over the years I have received a number of calls on the Colorado Potato Beetle.

When searching for ways to control the Potato Beetle I found information on products containing Spinosad, including Colorado Potato Beetle Beater by the Bonide Company. Products that contain spinosad also include Entrust, Captain Jack’s Deadbug Brew, Conserve, Monterey Garden Insect Spray and many others.

Mother Nature has provided us with Spinosad, a naturally occurring by-product of the bacteria Saccharaopolyspora spinosa. It was discovered in soil samples in an abanded Caribbean rum distillery by vacationing scientists. Use of spinosad containing products are approved for organic producers by the USDA National Organic Standards Board.

Products containing Spinosad are a natural alternative to control insects in the garden and for commercial vegetable and fruit producers. It is effective against many chewing insects like thrips, beetles and caterpillars but spares many of our beneficial bugs. It will also break down quickly in the environment by help of sunlight and soil microbes. It is very helpful to producers who have problems with insects that have developed resistance.

Spinosad is both a nerve poison and a stomach poison, so it kills pests that it contacts and those that consume it on the foliage they eat. It has a novel mode of action which will help prevent cross-resistance with organophosphates and carbamates (which are acetylcholinesterase inhibitors). Don’t go overboard on using spinosad containing products. Only three applications in a 30 day period are recommended. For the Colorado Potato Beetle, spray in the middle of a sunny day if possible.

Spinosad works well on chewing insects, so it must be ingested by the insect. Therefore it has little effect on sucking insects and non-target predatory insects. Spinosad is relatively fast acting. The pest insect dies within 1 to 2 days after ingesting the active ingredient.

The Colorado Potato Beetle (CPB) is the most economically damaging pest to potatoes in most areas of the United States, including West Virginia. If left uncontrolled, it can completely defoliate a potato crop. Although the potato is its favorite food, the beetle may also feed on tomato, eggplant, tobacco, pepper, ground cherry, petunia, and even cabbage crops. CPB has developed resistance to most registered pesticides, making it one of the most difficult insect pests to control.

The great thing about Spinosad is that it works on bugs that have developed resistance to insecticides on the market or are extremely hard to kill including the dreaded Potato Beetle, fall army worm, diamondback moth and European Corn Borer.

Spinosad can work to assist in pest control in important crops like tomatoes, peppers, eggplant, cole crops or leafy greens. Gardeners’ can control many major insect pests by using spinosad in combination with other natural insecticide like B.t. (Bacillus thuringiensis). This should allow for the survival of more beneficial insects and result in less pesticide use over the long haul.

On sweet corn, spinosad will control both European corn borer and fall armyworm. It also offers the opportunity to control moderate levels of corn earworm in an environmentally friendly manner.

Keep in mind that insects tend to seek out unhealthy, weak, or sick plants, and then send chemical signals to their buddies to come join the feast. As farmers and gardeners, it is very important to look at plant vitality and soil fertility. Strong, healthy plants are more resistant to disease and insect attack. Insecticides should not replace IPM (Integrated Pest Management) methods of crop rotation, planting disease resistance varieties, biological control with beneficial insects, and good management.

Looking for more information? Contact me at the Wood County WVU Extension Office 304-424-1960 or my e-mail jj.barrett@mail.wvu.edu with questions. Good Luck and Happy Gardening!


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