My job at Pullman, Washington, starting in 1965, was to control the root diseases of wheat and barley, focusing first on fusarium root and crown rot, then including take-all and pythium and rhizoctonia root rots. In the absence of viable alternatives,die agronomic approaches used were implemented through design of cereal-based cropping systems. Starting in the late 1970s, the mission focused further on cereal-intensive direct-seed (no-till) cropping systems. A team effort demonstrated the role of indigenous antibiotic-producing fluorescent pseudomonads in the widespread decline of take-all in response to monoculture wheat (or barley-wheat sequences). Today, the suppression of take-all by these beneficial rhizobacteria is the centerpiece of an integrated system that augments take-all decline while limiting pythium and rhizoctonia root rots and fusarium root and crown rot in direct-seed systems. In such systems, "crop rotation" takes the form of different sequences of winter and spring wheat, barley and triticale varieties, and market classes, all susceptible to all four root diseases.
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