Choosing pesticides for your lawn and garden needn't lead straight to reaching for chemicals. There are a range of environmentally...
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The vast array of garden chemicals at the nursery centers and home improvement stores can be bewildering. It is tempting to turn to chemicals to solve every problem.
Recently, however, we have all become aware of the environmental damage that overuse of strong chemicals can inflict, especially on our streams and rivers. In fact, you can have a healthy, attractive lawn and landscape without resorting to harsh chemicals.
There are only a few home landscape problems that require chemical intervention, and those can often be managed with simple horticultural oils or insecticidal soaps, both of which have very low toxicity.
Made from petroleum products or plants, there have traditionally been two kinds of oil used for pest control: heavier dormant oils, to be applied during the winter, or dormant season, to control unwanted insects, fungi and mites on fruit trees and woody ornamentals; and ultra-fine or summer oils, which are lighter and more highly refined, and may be applied throughout the growing season.
In recent years, better refining has made most oils acceptable for use year around.
Horticultural oils work in several ways. They block an insect's breathing holes, causing it to suffocate. They interfere with the cell metabolism in soft-bodied insects like aphids, scale, lace bug wooly adelgid, mealybug, whitefly, and some caterpillars.
Oils can disrupt the feeding patterns of certain disease-carrying insects and can even kill overwintering insect eggs and fungal spores.
Horticultural oils are very safe for the applicator and the environment when used according to label directions. Insects rarely develop resistance to oils, and they tend to evaporate quickly, leaving little toxic residue.
Oils are inexpensive, easy to mix and need no special spray equipment, making them ideal for homeowners.
Since horticultural oils have no residual effects, the target pest must be present when the oil is applied, and coverage must be thorough. Some plants are sensitive to oils; these are listed on the label. Treating bedding plants in flower may result in spotting of the flowers.
Insecticidal Soap is another low-toxicity pesticide. While all soaps are made of salts and fatty acids, not all soaps are good for killing insects. Some soaps can be highly destructive to plants and are useful as herbicides.
Insecticidal soaps, however, are specifically formulated to kill insect pests while having few adverse effects on people, plants and the environment.
Insecticidal soaps work on contact in two ways. First, they wash away the protective coating on the surface of the insect's body. Once inside, the soap will break the cell membrane and the cell will die. Insecticidal soaps are most effective on small, soft-bodied insects such as aphids, spider mites, thrips, whitefly and mealybug. They are only somewhat effective in controlling larger insects such as caterpillars and leafhoppers.
Insecticidal soaps have the advantage of generally being non-toxic to birds, mammals and people. They may be applied to both food and nonfood plants, and may even be used the day of harvest if necessary. As soon as the leaves have dried, beneficial insects can be reintroduced.
Insects must come in contact with the soap before it dries in order to be controlled. Therefore, thorough coverage to both tops and bottoms of leaves is essential. Multiple applications are needed to control most insects. It is best to apply soaps in the morning or evening when drying time is the longest.
Don't treat moisture- or drought -stressed plants, as the soap may damage the leaves. Avoid treatment when the relative humidity is 90% or above. Don't apply when temperatures are above 30 degrees.
Some plants may be sensitive to soaps and these are listed on the label. Some varieties of geranium, impatiens and poinsettias have shown injury with soaps. Test a small sample before making a full-scale application.
It is also important to note that while there are recipes for homemade insecticidal soaps, it is preferable to purchase a product that has been tested and approved for use as a pesticide.
For more difficult problems, stronger chemicals can be used sparingly to achieve maximum control with minimal peripheral effects.
Article provided by Lavender Pest Control