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Go organic this summer

Most of us have our gardens planted. Cool temperatures and plenty of rain have made insect control a non-issue. But we all know this honeymoon period will not last long. Summer is approaching and with hot, dry conditions come the insects.

Ideally, insecticides should reduce pest populations, be target-specific, break down quickly and have low toxicity to humans and other mammals. Although synthetic insecticides are very useful and have been important for many years, the disadvantages are becoming apparent. Some synthetic insecticides leave unwanted residues in food, water and the environment. Some are suspected carcinogens and low doses of many are toxic to mammals.

Seems to me that we get enough of that in the food we buy. In our own gardens we can control what goes on them and eventually what goes into us. There are many good organic products on the market. Organic gardening is still a challenge in the South and conventional insecticides may still need to be supplemented.

Some of the more useful organic insecticides currently available for homeowners are:

Spinosad: Spinosad is very effective against most caterpillar pests as well as thrips and leaf miners. It is sold under several labels including Greenlight Lawn and Garden Spinosad Concentrate and Bulls-Eye Bioinsecticide. Justice, Greenlight Fire Ant Bait with Conserve and Safer Fire Ant Bait are granular baits containing spinosad that are approved for fire ant control in organic crops. 

Bts: ‘Bt’ stands for Bacillus thuringienisis. Bts are naturally occurring soil bacteria that produce toxins that have insecticidal activity. There are many different strains of Bts. Some only control caterpillar pests, while others only work on mosquito larvae. Bts are generally slow acting. Thuricide and Dipel are examples of Bt products commonly sold. Bts work best used when caterpillars are small.

Azadirachtin: Azadirachtin is a natural insect growth regulator derived from the seed of the neem tree. It is especially effective against sucking insect pests, such as whiteflies and aphids. Since it is a growth disruptor, it is slow-acting. Azatrol is one example of an organic azadirachtin product labeled for homeowner use.

Neem Oil: Neem Oil is obtained from the seed of the neem tree. It controls soft-bodied insects such as aphids and whiteflies and is helpful in controlling some diseases. GreenLight Neem Concentrate, Garden Safe Fungicide 3-in-1 Concentrate and Monterey 70 percent Neem Oil are examples of these products.

Pyrethrin: Pyrethrin, also known as pyrethrum, is a natural extract from a flower. It is a broad-spectrum insecticide that affects most insects through contact activity. It is short-lived and many pests may be ‘knocked down’ only to recover later. Repeat applications may be necessary.

Safer Yard and Garden Insect Killer and Pyganic are examples of this product.

Iron Phosphate: Several companies make a slug bait containing iron phosphate. These products are generally safer for use around pets than baits containing metaldehyde. Sluggo and Garden Safe Slug and Snail Bait are iron phosphate based baits.

Horticultural Oils: Petroleum based oils are useful for control of scale insects and soft-bodied insects such as aphids, spider mites and whiteflies. Volck, Bonide All Seasons Oil Spray and Fertilome Dormant and Summer Oil Spray are available.

Plant oils and fish oils: There are several organic oils made from fish oil or various plant seed. These are effective against aphids, mites and whiteflies. Golden Pest Spray Oil is made from soybeans. Vegol Year-Round Spray Oil is extracted from canola seed and Organocide is a combination of fish oil and sesame oil.

Rotenone: Rotenone is a botanical insecticide derived from several different plants. It is moderately effective against beetles and true bugs, such as stink bugs and plant bugs. Bonide Rotenone and Pyrethrum Spray is one product available.

Insecticidal Soaps: Insecticidal soaps are potassium salts of fatty acids. Insecticidal soaps are useful for control of soft-bodied insects. Be sure to follow the label recommendations; these products may cause foliar injury. Safer’s Insecticidal Soap is a good product.

The key to successful organic gardening in the South is to grow plant species and/or varieties that are relatively pest free, to keep these plants healthy and vigorous and to be willing to tolerate low to moderate levels of insect infestation. Going totally organic may not be possible during certain times of the year, but every little bit helps.

Rebecca Bates is director of the Lincoln County Cooperative Extension Service. To contact her, call 601-835-3460