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Show when quackgrass has reached the three to four leaf stage can provide 90 percent control when followed by an effective seedling control program, according to tests conducted at the University of Minnesota. Farmers Interested In further Information about quackgrass and existing control con-trol options may obtain a free brochure by writing to: Monsanto Agricultural Products Pro-ducts Co.,800 N. Lindbergh Blvd., Dept. C3SD, St. Louis MO 63166 unlfested fields." Dr. Cal-lihan Cal-lihan does say that tillage may work In fallow situations where drier conditions will naturally destroy quackgrass. quack-grass. Calllhan claims many farmers have found that fall application of Round -up herbicide, her-bicide, a non selective, "translocated" chemlcal.ls probably the most effective technique for control of quackgrass. "Fall application applica-tion of Roundup is a key treatment in these areas," he states. A post -harvest application of the two to three quart per acre rate " IwaeEifpse, a km psilSn Quackgrass, a weed which infests some 11.5 million acres nationwide in crops ranging from soybeans to potatoes, can be a particularly particu-larly tough problem for Utah wheat and barley growers. Thriving under conditions that promote optimum small grain production, quackgrass quack-grass is capable of cutting yields significantly wherever wher-ever it appears. "Quackgrass has been a problem here for 40 years andl see no indication that Infestations are abating," says Dr. Robert Calllhan, associate professor of agronomy ag-ronomy at the University of Idaho, a state where about 15 percent of the irrigated cropland is infested to an economic degree. "I'd estimate esti-mate that a heavy infestation of quackgrass is capable of reducing wheat and barley yields by 75 percent. Left untreated, it also drastically cuts the yield potential of such rotation crops as sugar beets and potatoes." Dr. Callihan estimates that severe infestations are scattered throughout the wheat belt, espelcally In Idaho, Oregon, Washington, North Dakota, Co lor ado,Utah and Montana. "Quackgrass flourished under conditions of cool temperatures and more than 15 "Inches of rainfall rain-fall or irrigation water," Dr. Callihan explains. And because there have been a few effective techniques for control In such areas until recently, quackgrass infestations infes-tations have intensified." Fast -Growing Rhizomes: Quackgrss owes its ability to overtake fields to a dual reproductive system. It reproduces re-produces through both seedlings seed-lings and a system of underground under-ground rhizomes capable of producing up to 450 feet of new rhizomes and sending up 200 shoots ina single sea-son,accordlng sea-son,accordlng to Dr. Sheldon Blank, a weed control specialist spec-ialist for Monsanto. In addition, ad-dition, university tests indicate indi-cate that these rhizomes are capable of producing a toxic substance which can inhibit the germination and growth of other plant seedlings. "With the weed itself competing com-peting for moisture, light and nutrients, and the growth inhibitor weakening germinating germi-nating seeds, effective quack grass control is a matter of utmost urgency," Dr. Blank cautions. "The farmer who leaves quackgrass infestations infesta-tions untended is in effect surrendering his fields to the weed. Within two season, he'll end up with a mat of intertwined rhizomes which will be impossible to till and difficult to treat.' But, farmers In the wheat producing states have had few viable options for controlling con-trolling quackgrass. "Tillage "Til-lage Is not an option for grain farmers with quackgrass" quack-grass" infested fields,"Says Dr. Callihan. "Often this kind of treatment results In a more widespread infestation. infesta-tion. The tillage equipment after cutting the rhizomes into segments, can drag these segments and transplant trans-plant the weeds in previously |