Sulc R M, Rhodes L H
Assistant Professor, Department of Horticulture and Crop Science.
Associate Professor, Department of Plant Pathology, The Ohio State University, Columbus, 43210.
Plant Dis. 1997 Jan;81(1):13-17. doi: 10.1094/PDIS.1997.81.1.13.
This study was conducted to determine the effect of planting date, fungicide, and cultivar on severity of Sclerotinia crown and stem rot (SCSR) and subsequent productivity of alfalfa. The cultivars Armor and A9109 were seeded no-till in May, early August, mid August, and late August 1993 and 1994 in a sod uniformly infested with sclerotia of Sclerotinia trifoliorum. Four applications of the fungicide vinclozolin effectively controlled the disease. Averaged over years and cultivars, disease severity (percentage of plot area affected) in the no-fungicide treatment was 4, 12, 23, and 41% for the spring, early August, mid August, and late August plantings, respectively. Armor had higher disease severity than A9109 in the 1993 seeding, but not in the 1994 seeding. Forage yield the year after seeding reflected differences in disease severity ratings. The risk of severe SCSR damage in no-till summer seedings of alfalfa can be reduced dramatically if stands become established early enough so plants reach at least 10 weeks of age by the time apothecia emerge in the fall.
本研究旨在确定播种日期、杀菌剂和品种对苜蓿核盘菌冠腐病和茎腐病（SCSR）严重程度以及后续生产力的影响。1993年和1994年5月、8月初、8月中旬和8月末，在均匀感染三叶草核盘菌菌核的草皮中免耕播种了Armor和A9109品种。杀菌剂乙烯菌核利的四次施用有效控制了该病。多年和品种平均来看，在无杀菌剂处理中，春季、8月初、8月中旬和8月末播种的病情严重程度（受影响地块面积百分比）分别为4%、12%、23%和41%。1993年播种时，Armor的病情严重程度高于A9109，但1994年播种时并非如此。播种后一年的牧草产量反映了病情严重程度评级的差异。如果苜蓿免耕夏播时立苗足够早，以至于到秋季子囊盘出现时植株至少达到10周龄，那么严重SCSR损害的风险可大幅降低。
