INVASIVE WEED CONTROL

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DoD perspective on invasive weed control

Captain Gary Breeden, USN, Executive Director,

Armed Forces Pest Management Board

The Armed Forces Pest Management Board got its start during World War II

when Marines became ill at Guadalcanal. After living under various umbrellas, it

eventually found its current home with the Department of Defense (DoD). The

Board is concerned with environmental compliance within the DoD. A major role

is to bring rational, science-based information to the decision-making process,

providing the needed counterpoint to the political and emotional aspects of

decisions.

Current issues include dealing with range encroachment (urbanization near

facilities) and acting as good stewards of the environment.

Chemical control of invasive weeds

Lisa Moore, DuPont Chemical Company

There are many reasons to control undesirable vegetation. In addition to dis-

placing native ecosystems, undesirable plants create roadside hazards, provide

fuel for wildfires, and become nuisances in recreation areas and around our

homes. Two Executive Orders on invasive species and the use of native plants

direct Federal agencies to control and monitor invasive species, prevent the

introduction of invasive species to new areas, and restore native species.

The toolbox of control methods includes biological controls, such as insects;

cultural controls, such as making the site strong enough to resist weed invasion;

mechanical controls, such as mowing, pulling, cutting, burning; education to

prevent poor vegetation management practices; and chemical controls.

Toxicity of chemicals

When using chemicals, it is important to understand how to use them

properly as well as be aware of their toxicity. Relative acute toxicity may

be compared using the LD50 measure (the dose required to kill half of a rat

population), which is the federal standard in determining pesticide toxicity.

Common herbicides vary from almost non-toxic to highly toxic (Table 4). By