![]() The purple variant, which is very rare, has only been reported once outside of the western Nebraska Panhandle - from cull bean seeds in Alberta, Canada, in 2006. The purple variant maintains a yellow-colored colony in culture, but produces an extracellular, water-soluble bright purple pigment that diffuses into growth medium within two to three days ( Figure 9) and also discolors seed. Note that not all seeds are infected or discolored.Ĭolony growth and staining of seeds reported for original isolates of Cff were always yellow until orange- and purple-colored variants were found in western Nebraska. One pod of wilt-infected dry bean plant showing discolored seeds (top) inside a pod with no external symptoms (bottom). Dry bean plant surviving to harvest but producing discolored seeds as a result of wilt infection.įigure 8. Symptoms on adult plants are less pronounced as the disease generally develops and progresses more slowly.įigure 7. Seedlings are particularly susceptible, and if attacked when 2-3 inches tall, usually die ( Figure 2). Disease severity and plant mortality are often higher on young plants or those growing from infected seed. Plants often recover during evening hours when temperatures are lower but wilt again during the heat of the day. This occurs because of the pathogen’s presence within the vascular system, which blocks normal water movement from roots into the foliage. Disease incidence in these fields has varied from trace levels to >90 percent.įield symptoms consist of leaf wilting ( Figure 1) during periods of warm, dry weather or periods of moisture stress. Affected fields were planted with dry beans from multiple market classes and seed sources, including yellows, great northern, pintos, kidneys, cranberries, blacks, navies, pinks, and small reds. Over the last seven to eight years, it has fully re-emerged in the Central High Plains (Nebraska, Colorado, and Wyoming) and has now been identified from more than 400 fields. The pathogen was again identified in 2003 for the first time in this area in almost 25 years. The disease then only periodically appeared in seed, but had little detectable effect on yields after the implementation of crop rotation and seed sanitation practices. It was first observed in western Nebraska dry bean production fields in the early-mid 1950s, and continued to be an endemic, economically important problem throughout the 1960s and early 1970s. flaccumfaciens ( Cff), has been a sporadic - but often serious - production problem in dry beans throughout the irrigated High Plains since first being reported in South Dakota in 1922. Bacterial Wilt Importance and Managementīacterial wilt of dry beans, caused by Curtobacterium flaccumfaciens pv.Schwartz, Extension Plant Pathologist, Colorado State University This NebGuide addresses symptoms and identification, life cycle, and management of bacterial wilt in dry beans. G1562 Bacterial Wilt of Dry Beans in Western Nebraskaīacterial wilt of dry beans has reappeared in Nebraska dry bean fields. ![]()
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