Johnson Dennis A, Cummings Thomas F
Department of Plant Pathology, Washington State University, Pullman 99163-6430.
Plant Dis. 2015 Feb;99(2):257-262. doi: 10.1094/PDIS-03-14-0271-RE.
Potato tubers were collected and evaluated for symptoms and signs of black dot, silver scurf, and Verticillium wilt to determine the effect of extended crop rotations on disease incidences in the Columbia Basin. Incidence of tubers with black dot collected from storage significantly decreased as the number of years between potato crops increased from 3 to 5 years and beyond and significantly increased as the number of previous potato crops increased to 16. The highest incidence of black dot (range of 73 to 98%) was from fields rotated out of potatoes for 1 to 3 years. The mean incidence of black dot was 56% for fields out of potatoes for 0 to 4 years and 12% for fields out of potatoes 5 and more years. A low incidence (0 to 9%) of black dot was detected at 15 years out of potatoes. Years out of potato and number of prior potato crops accounted for 71% of the variability associated with the incidence of black dot. Severity of black dot on tuber periderm peels significantly increased as incidence of tuber periderm peels with Colletotrichum coccodes increased. Coefficient of determination was 0.87 for log severity on regressed on black dot incidence. Incidence of silver scurf was highest from fields out of potatoes for 1 year. Incidence of silver scurf infected tubers significantly increased as the number of previous potato crops increased due to short rotations between potato crops. Incidence of tubers with Verticillium dahliae was not related to years between potato crops or number of previous potato crops. The present study confirmed that black dot can be reduced with rotations out of potatoes greater than 5 years.
收集马铃薯块茎并评估其黑点病、银皮病和黄萎病的症状及病征，以确定延长轮作周期对哥伦比亚盆地病害发生率的影响。从贮藏中收集的有黑点病的块茎发生率，随着马铃薯作物种植间隔年限从3年增加到5年及更长时间而显著降低，随着之前马铃薯作物种植次数增加到16次而显著增加。黑点病发生率最高（73%至98%）的是马铃薯轮作1至3年的田地。马铃薯轮作0至4年的田地中黑点病的平均发生率为56%，轮作5年及更长时间的田地中为12%。在马铃薯轮作15年时检测到黑点病的发生率较低（0%至9%）。马铃薯轮作年限和之前马铃薯作物的种植次数占与黑点病发生率相关变异的71%。随着带有围小丛壳菌的块茎周皮发生率增加，块茎周皮上黑点病的严重程度显著增加。黑点病发生率回归后的对数严重程度的决定系数为0.87。银皮病发生率在马铃薯轮作1年的田地中最高。由于马铃薯作物之间轮作时间短，随着之前马铃薯作物种植次数增加，感染银皮病的块茎发生率显著增加。带有大丽轮枝菌的块茎发生率与马铃薯作物之间的年限或之前马铃薯作物的种植次数无关。本研究证实，马铃薯轮作超过5年可减少黑点病。
