云南马铃薯粉痂病发生情况初步研究

马铃薯粉痂病由Spongospora subterranea f.sp.subterranea引起,是典型的土传病害,主要危害块茎和根部。2004年调查了昭通市和会泽县7个乡镇,8个马铃薯品种的粉痂病发生情况。在调查的品种中,会-2发病最轻,平均发病率27%。会泽县马铃薯粉痂病平均发病率59%,昭通市马铃薯粉痂病平均发病率35%。分析土壤中氮、磷、钾、有机质含量及pH与发病率的关系。PB06发病率与土壤中氮、有机质呈正相关,与磷、钾、pH呈负相关,其中与钾含量相关系数为0.693。会-2发病率与土壤pH、钾含量呈负相关,相关系数分别为0.384、0.858,其中与钾含量相关性显著;与磷、有机质含量呈正相关,相关系数分别为0.727、0.323;与氮含量呈正相关,相关系数为0.993,相关性显著。

A preliminary study on the occurrence of potato powdery scab in Yunnan Province

Powdery scab is a typical soil-borne disease of potato caused by Spongospora subterranea(Wallr.) Lagerheim.The pathogen produces scab or blister on the tuber surface.It causes severe tuber distortion and reduces the market value of the crop.Meanwhile,it also produces wart-like galls on the roots.Eight potato cultivars were investigated in 7 villages and towns in Zhaotong and Huize for the incidences of powdery scab in 2004.The results showed that the average incidence of cultivar Hui-2 is 27%,which is the lowest in all cultivars investigated.The average incidence of Huize is 59%,whereas that of Zhaotong is 35%.Correlation analyses between the content of N,P,K and organic substances in soil and the incidence of powdery scab found that the incidence of PB06 decreased with the reduction of the content of N and organic substances or the increase of pH,K and P.The incidence of Hui-2 decreased when pH and K increased or P and organic substances decreased.Their correlation coefficients are(0.384),(0.858),0.727 and 0.323,respectively.The incidence of Hui-2 is significantly related to the content of N in soil,with the correlation coefficient as 0.993.