Comparison of cultural and chemical measures of controls on Rhizoctonia disease of potato

Rhizoctonia canker, also known as stem canker and black scurf of potato, Rhizoctonia solani Kuhn, causing serious economic losses by canker on under ground stem, roots, stolens, blanding of tubers and black scurf on potato surfacee in Isfahan. In this manscript, the effects of green chitting and or disinfection of potato seed tubers and soil were considered on this disease in the fields. The laboratory trails on R. solani isolates indicated that, almost all the sclerotinia are pathogenic. The seed tubers of four potato cultivars were selected and kept under room temperature along with normal light and high humidity for two months. Then, they were sown in the highly infested soil to the disease. The results indicated that the green chittings reduced Rhizoctonia stem canker severity effectively. In comparison to the above experiments, the fungicide screening, Rovral in the form of seed, soil and simultaneous seed and soil applications were carried out in the same fields. The results showed that the stem canker severity was reduced effectively compared to chittings and that of control. Increased growth response was observed in only green chitted potato seed tubers compared to other treatments.