Pesticides come in several different categories and each has a descriptive name based on what the pesticide controls. This is a list of pesticide types followed by the pest they manage: insecticides control insects; fungicides -- fungi; herbicides -- weeds; miticides -- mites; and rodenticides -- rodents such as rats and mice.
Insects are one of our primary pests, so many people use insecticides. For years, insecticides like Dursban and Diazinon were very common. Homeowners liked to use these insecticides because they killed a wide variety of pests and the effects lasted a while.
These insecticides were withdrawn from the homeowner market several years ago due to potential health risks.
When these chemicals were withdrawn, a class of insecticides called the pyrethroids took their place.
The pyrethroids tend to be lower in toxicity to people. This is a good thing. Pyrethroids still kill insects quickly and are less toxic in some environmental settings.
Pyrethroids, however, tend to cling to soil. Research shows that they are building up in the sediment of our streams, rivers and lakes. Pyrethroids are also toxic to aquatic life -- fish and benthic invertebrates. Benthic invertebrates are the small creatures without a backbone that live in the sediment in the bottom of bodies of water. Pyrethroids can kill these invertebrates that are the basis of the food chain in aquatic environments. In this way, pyrethroids can affect all creatures near the water -- fish, birds, mammals, etc.
How do you know if you are using a pyrethroid? Read the label. The name of the active ingredient is in small print on the label. If the name ends with -thrin or -ate, then it is a pyrethroid. Examples include cyfluthrin, permethrin and esfenvalerate. These are synthetic pyrethroids. One thing to note that you may find pyrethrin, as well, but it is a naturally derived chemical that breaks down more quickly than pyrethroids. (I usually do not get this technical in my columns, but I wanted you to understand what you are using.)
Commercial pesticide applicators will see changes in the way that pyrethroids are labeled to be used. Homeowners can also help prevent pyrethroids getting in streams as well by following a few simple rules when using pyrethroids.
Using a pesticide is not necessarily bad for the environment. We just need to be careful.
We all use chemicals every day that can be toxic -- gasoline, medicines, cleaners, bleach and paint. We just need to use chemicals safely. Here are some tips to use pyrethroids (and other pesticides) so that they have less effect on the environment. For more ideas, see this website where I got some of this information: http://citybugs.tamu.edu/2012/02/20/using-pyrethroids-safely/.
Do not spray or apply granular insecticides to hard surfaces. These are easily washed off in a rain and may end up in storm drains, which drain directly to our streams and rivers. Sweep up any insecticide granules that end up on drives, walks and roads. Apply the granules instead to lawns and flower beds, where they are meant to be used. You can spray insecticides on cracks around buildings, but do so lightly and do not spray large areas.
Never pour insecticide residue down a drain or storm drain! The storm drain water goes directly to the river untreated and the water treatment system for our drain systems may not be able to de-toxify the insecticide. The best use for excess pesticide is to use it according to its labeled use. If you have excess pesticide to discard, contact your local extension office for details, (800) ASK-UGA1.
Read and follow all label directions on pesticides. These are not recommendations, the label represents the law concerning how pesticides can or cannot be used. To ignore the label is to ignore the law!
If allowed by the label or instructions, water in insecticides as soon as application as possible. This helps to keep the insecticide in our lawn and out of our streams.
Do not spray or mix pesticides, etc., near a body of water, storm drain or a well. Keep pesticides at least 10 to 30 feet away from bodies of water -- farther is better. Do not spray if it is windy to prevent pesticide drift into water.
Willie Chance works with the University of Georgia Center for Urban Agriculture.