NATURAL BORN KILLERS

Eco-friendly products safe way to control insects

The Post and Courier

Seinfeld was right. Breakfast cereal rules.

After drudging through the produce, flour and spaghetti sauce, my brother and I used to think the cereal aisle was like a mini-holiday. We picked out our own box and, if dad was at work, we would pour a bowl as soon as we got home. The chocolaty, sugary, artificially fruity tasting flakes were so good they should've been illegal. I could demolish a box of Fruity Pebbles in one sitting.

There was only one problem. With so many great cereals, how could we pick just one? Sometimes it was torture. Pest control is like the cereal aisle: There are so many options it can be mind-boggling. Will it work? Is it a healthy choice? Is there enough fiber?

Some pesticides are risky to the handler and the environment. However, there are many natural, safe products. Repeat applications might be necessary because these products are not as toxic, but they can get the job done.

Besides safety, another advantage of natural pest controls is that they typically have minimal effect on beneficial insects. While synthetic insecticides effectively kill pests, they also kill the good guys that feed on them. This can incite a vicious cycle. When insect pests recover from an application, there are no beneficial insects marching around to eat them. This, in turn, can make the next outbreak even worse.

Insecticidal soap

Insects are small and susceptible to drying out. They have an outer waxy coating called a cuticle to retain moisture. A soapy solution strips the cuticle away and leaves insects with a lethal case of 'dishpan hands.'

You can mix up your own soapy spray by adding 2 ounces of liquid soap per gallon of water. The problem with mixing your own is the mixture's tendency to foam. Soapy products, such as M-pede, contain anti-foam adjuvant that makes application easier and more uniform. Soaps must make contact with the insect to work.

Soaps control small, soft-bodied insects, such as aphids, although results can vary. Mixed strong enough, they will control caterpillars. They also have been used to control powdery mildew disease. Soapy solutions are commonly used to sample for mole crickets, too. Pour a gallon on the lawn and mole crickets, spiders and earwigs come to the surface.

Keep in mind that leaves also have waxy cuticles to retain moisture, and soap will strip them, so avoid applications during hot, dry weather (read the label for specifics).

Horticultural oil

Insects breathe through holes called spiracles along their back ends (abdomen). Horticultural oil coats these openings and suffocates the insect. It also has been used to smother eggs, scale insects in particular.

Years ago, these products were called dormant oils because they were heavy and were recommended only during the winter. Oil products today are more highly refined (referred to as summer weight) and can be used throughout the year on all plants.

Like soaps, oils are best used on small, soft-bodied insects such as aphids and whiteflies. And it's best to avoid hot weather (read the product label for specifics). Oil applications must make contact with insects.

Bacillus thuringiensis (Bt)

Bt is a bacteria that produces a crystalline toxic protein (an endotoxin). There are many types of Bt, but the most popular one, found in Dipel and Thuricide products, kills only caterpillars.

Bt is a stomach poison that bores a hole through the insect's stomach, so it must be eaten in order to work. Caterpillars stop feeding immediately but may take several days to die. The product does not have to make contact with the insect, but it may only be active on plant surfaces for a few days.

The Bt protein became a source of controversy when it was genetically bred into corn to control European corn borers (caterpillars). There are no adverse affects on humans, but there is evidence that monarch caterpillars are affected by the pollen (studies are ongoing).

There are Bt varieties such as Bacillus thuriengiensis ‘israeliensis' that control mosquito larvae. Products come in granules or donut-shaped dunks that are applied to stagnant water where mosquitoes breed.

Spinosad

Spinosad is an insecticide derived from a bacterium. It is more broad-spectrum than Bt, controlling many caterpillars, beetles, thrips and flies. It is sold under a variety of brand names, such as Conserve and Entrust.

Spinosad kills insects by overstimulating the nervous system. The muscles continuously fire for a few days before breaking down. Sort of like one too many trips to the coffee pot.

Diatomaceous earth

Diatomaceous earth is a fine white powder (mostly silica) that comes from fossilized remains. It is typically used to control household insects such as cockroaches and ants. The powder contains sharp crystallized particles with such high absorptive capacity that it breaks down the outer cuticle and dries out the insect.

The product is applied behind appliances, along window sills or wherever household insects might be. It is not toxic to humans but can pose a serious inhalation risk, so read the label and follow the instructions.

Milky spore disease

This bacterium (Bacillus popilliae) creates a deadly disease in Japanese beetle grubs. It does not control the adult or most other white grubs. White grubs are not a problem in the Lowcountry, but Japanese beetles can be.

This product is applied to the soil and, over the course of a couple years, becomes established to infect Japanese beetle grubs. That doesn't mean Japanese beetles won't fly in from your neighbor's yard. In this respect, the treatment is more effective when used communitywide.

Botanicals

Insecticidal products obtained from plants are called botanicals. As a group, they are much safer than synthetic insecticides, but they tend to kill a broad spectrum of insects, including beneficials.

Pyrethrum, distilled from chrysanthemum, is one of the most popular. It is fast-acting (good for wasp spray) but not exceptionally lethal. Pyrthroids, such as Talstar and Raid, are synthetic versions of pyrethrum and are fast becoming popular insecticides because they are safer than many synthetics.

Neem oil is derived from the neem tree. It has a long history of medicinal and cosmetic usage. The active ingredient inhibits insect growth by interrupting the ability to molt. Since we don't molt, it's safe for us. It's effective against a lot of insects, including aphids, whiteflies and caterpillars, although thrips are somewhat resistant.

Rotenone is a longtime favorite of gardeners. Obtained from the roots of tropical plants, rotenone is a broad-spectrum insecticide. Although it is mildly toxic to humans, it is highly toxic to fish, so it should be used with care around water.

Finding products

Insecticidal oils and soaps are widely available. Finding the other products mentioned here can be hit or miss. Check with local garden centers and pesticide retailers, or order online at places such as www.biconet.com or www.planetnatural.com.

As always, read the label of any product you use. Cold cereal wasn't my only morning vice. I also ate Cream of Wheat, the Yankee version of grits. It didn't say so on the label, but I always added a half a cup of sugar before I thought it was any good. Of course, I'd have to do that before the old man got downstairs.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback or request specific column topics, e-mail Tony at tony.bertauski@tridenttech.edu.