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Weed Warrior

PROSSER, Wash. — When Bob Parker drives the back roads of south central Washington, plumes of dust rising in the wake of his pickup, he looks at things a little differently than you or I.

We may gaze at the scenery or observe how well the crops are doing. He scans the landscape to gather intelligence on his lifelong nemesis: weeds.

The Washington State University Cooperative Extension weed scientist is on the front lines of a never-ending battle against plants that each year cost U.S. farmers billions of dollars to control and in lost production.

What is a weed, you ask? Parker will tell you that a weed is simply a plant that is growing someplace it’s not wanted. And that may include plants we normally regard as desirable.

“One of the problem weeds we have in the irrigated area of Washington is potatoes that volunteer from the previous potato crop,” Parker said. “They are a weed problem for the potato grower because they are a potential source of disease for the following year’s crop.”

How many different weeds are there? Nobody really knows. Parker, whose speciality is weeds that infest irrigated crops and aquatic weeds, says there are at least 40 in mint, grown in the Yakima Valley and Columbia Basin for its aromatic oil.

Parker’s role in the war against weeds is one of educator and advisor. He supports the educational efforts of WSU county extension faculty across the state. He also conducts 30 to 50 training sessions a year for farmers, chemical dealers, pesticide applicators, and representatives of various governmental bodies concerned about controlling weeds along roads and on public lands.

Parker also spends a lot of time on the phone and in the field, helping homeowners and growers identify weeds and suggesting measures to control them.

“One of the weeds we’re getting quite a few calls on lately is kochia,” Parker says. “Kochia is quite competitive against crops. It tumbles somewhat like Russian thistle, so it spreads fairly easily and It can grow large enough to hide stop signs along roads. We had a couple spots of it when I arrived here in 1978. It’s now all over Eastern Washington.”

He says another weed that is making its presence known is purple loosestrife, originally introduced as an ornamental from Europe. The perennial can grow to eight- feet in height and produces showy purple flowers along its stem. It thrives along waterways, sometimes excluding other plants. “It got away from us,” he said.

Parker also gets calls on tough-to-kill perennials like field bindweed, a cousin of the morning glory that creeps up your backyard trellis.

Why is field bindweed so tough to kill? “Deep roots, roots that go down maybe 25 feet,” Parker says. “It’s hard to get chemicals all the way through the root system. It has great potential to regenerate itself.”

If that’s not enough, the weed’s seed can lie dormant for half a century and still germinate.

There have been some success stories. “We’ve pretty well controlled Johnsongrass. We found it in several different crops and several different areas along roadsides, but mostly in small patches. People got to it right away and pretty well controlled it.”

Johnsongrass, which is native to the Mediterranean region, was introduced for use as a hay or forage crop. It produces stems that can grow to eight feet and spreads by seed or rhizomes. Under mositure stress or frost, the plants produce an acid that is toxic to livestock

During 19 years with WSU, Parker has seen weed control measures shift from a heavy reliance on herbicides to a greater use of integrated pest management techniques, including use of better-adapted crop varieties, more timely irrigation and more careful planting all help the crop be more competitive against weeds.

Parker holds three academic degrees, has served on many state, national and international committees and has written or served as a co-author of nearly 200 extension bulletins, articles for refereed journals and “Weeds of the West,” a 650-page reference book. The Washington State Weed Association has honored him for years of service.

Nevertheless, Parker is still learning. “You never can talk to a grower or somebody in the field without learning something from them. Ph.D.’s don’t have a corner on knowledge. I’ll tell you that.”

“Weeds of the West, ” a paperback guide to 300 weeds commonly found in the West, can be ordered by writing the Bulletin Office, Washington State University, P.O. Box 645912, Pullman, WA 99164-5912. Cost is $23 plus $5.50 for shipping and handling. (Washington residents must also pay 7.5 percent sales tax on the cost of the book.) Make checks payable to Cooperative Extension Publications.

Visa or MasterCard orders can be placed by phone. Call (509) 335-2857 during normal business hours.

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