Herbicides can be useful tool

Sunday, August 7, 2005

Special to the Southeast Missourian

Wildlife managers utilize many tools to manage land for wildlife and native plant communities. Tractors, disks, mowers, chainsaws, planters and other equipment are used to manipulate vegetation and change the composition of land to improve habitat conditions. These tools are essential to create and maintain good habitat conditions.

Surprisingly, many people do not realize that herbicides -- chemicals used for vegetation management -- also are used more frequently by conservation agencies.

Isn't the use of chemicals harmful to the environment? Are we forgetting the message of Rachel Carson's "Silent Spring," which brought to the world's attention the harm chemicals can do to our sensitive ecosystems? How can agencies which are responsible for the protection and preservation of the environment consider using pesticides?

To answer those questions, we must look at past pesticides and herbicides and compare them to present products. Much of the past concern was related to insecticides -- chemicals that target insects -- and their persistence in the environment.

In the past, DDT and other insecticides were sprayed indiscriminately to control mosquitoes and other nuisance insects. Because of their toxicity, many wildlife species and other nontarget animals would be killed outright or develop long-term health problems. In addition, most pesticides used then were very persistent and would accumulate in the fatty tissue of long-lived animals, including humans, eventually causing health-related problems.

Few pesticides or herbicides were tested for safety and no safeguards were in place to insure the chemicals were safe or applied correctly.

Today, pesticides and herbicides are much safer. Before they are allowed on the market, they are extensively tested, much the same as human drugs. Tests determine what effects they will have on humans and the environment and how long the pesticide will persist. Agencies such as the EPA regulate pesticides. Most states also have laws and regulations requiring that pesticide applicators, both commercial and private, be trained before using any pesticides deemed to be harmful. These safeguards have produced many herbicides that have no harmful effects on animal life.

Many of today's agricultural herbicides target either specific types of plants or plant communities and will do no harm to nontarget plants. Though we still do not understand all of the effects herbicides have on the environment, they are much safer than in the past.

Herbicides offer safe and cost-effective alternatives to mechanical methods such as tillage, chainsaws and mowing which can be destructive to natural ecosystems. They also reduce workers' exposure to injury from mechanical equipment. With proper selection and correct use, managers can employ herbicides to enhance wildlife benefits on conservation lands. In many cases herbicides may be the only management option to control a problem plant without harming native plant communities.

Wildlife managers, including those managing private land, view herbicides as a tool, just like any other implement they would use to manipulate habitat. They must evaluate its usefulness in each situation for effectiveness, cost and desired results.

Larry Heggemann is a private land conservationist with the Missouri Department of Conservation.

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