INSTAAR Science Spotlights 2001

CU Professor Tim Seastedt honored for weed control research

Text taken from the official Congressional Record Online:

HON. MARK UDALL of colorado in the house of representatives
Wednesday, October 17, 2001

Mr. UDALL of Colorado. Mr. Speaker, I rise today to acknowledge the important work of University of Colorado Professor Tim Seastedt in weed control research. Professor Seastedt's exciting and path-breaking research on using insects and soil chemistry to control the spread of noxious, non-native plants holds promise in addressing a vexing--and spreading--problem, especially on our western lands.

Professor Seastedt's work was recently recognized through a $280,000 grant awarded to him by the U.S. Department of Agriculture to continue his work of examining the soil chemistry of diffused knapweed and devising a way to develop soil nutrients that kill or hamper the growth of this problem weed in Colorado and elsewhere. Through this grant and his existing work on the role of insects in controlling the spread of weeds, Professor Seastedt is demonstrating that we can address our weed problems and do so in an effective and environmentally sensitive manner.

The nature and extent of the weed problem in the west is dramatic and serious. In Colorado alone, there are 85 species of weeds that are taking root in millions of acres of rangeland, have displaced nearly 10 percent of the state's native plant species, have destroyed habitat for bighorn sheep and other wildlife, and caused upwards of $100 million in lost crop productivity annually. Similar impacts exist in many other states.

Weeds get here and take hold for a host of different reasons. In the case of diffused knapweed, it is theorized that this plant came over from Europe from imported alfalfa crops. But no matter how they get here, once these plants take hold they are very hard to eradicate. In North Dakota, for example, where another plant--leafy spurge--is a particularly bad problem, the state has been spending nearly $100 million a year to control it. Such controls involve everything from herbicides, mowing, hand-pulling, and the use of grazing animals such as sheep--all to little or no effect. The plants keep coming back. In addition, some of these methods, such as the spraying of chemical herbicides, are controversial as they may be harmful to the environment.

That's where Professor Seastedt's work comes in. Given the cost, low-effectiveness and environmental concerns of these traditional methods, Professor Seastedt and his researchers began looking for better methods. He latched on to insects. For example, in the case of diffused knapweed, Professor Seastedt found that a number of species of weevil feed upon the roots, stems, seeds and flowers of this plant. So, he released a swarm of them in test plots along Colorado's Front Range, an area especially hard hit by this weed. The result: where there once were 30 stems of diffused knapweed per square meter, there now are hardly any at all. And native grasses and plants, which are not palatable to the weevils, are now making a strong return. This story is being copied in North Dakota with the leafy spurge. There is a species of insect called flea beetles that seems to thrive on this weed with the result of reducing by half the acreage that has been affected there. This insect is now being used to control the leafy spurge problem at Colorado's Cherry Creek State Park, which has resulted in a 60 percent reduction of the growth of this weed at this popular state park.

Insects are thus proving to be an exciting tool in our arsenal against weeds. The other weapon is the new research on soil chemistry. Professor Seastedt has been studying the soil conditions that are favorable to diffused knapweed. He has found that some nutrients are more favorable to this plant than others. Armed with this knowledge, it may be possible to use natural elements of the soilto enhance the growth of favorable plants and retard the growth of harmful ones like diffused knapweed. The grant from the U.S. Department of Agriculture will help him continue this research.Professor Seastedt's success in this regard will further help restore the health of our lands, increase agricultural productivity, and enhance the quality of life in the west. I look forward to the continuing work of Professor Seastedt and his researchers on our ongoing struggle to get ahead of and win our war with weeds.

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