Effect of Wuyiencin on the Growth and Development of Corn Sheath Blight (Rhizoctonia solani)

Corn sheath blight (Rhizoctonia solani) has been the most important disease on maize crops in many major corn‐grown regions of China and wuyiencin is an antibiotic fungicide derived from Streptomy‐ces ahygroscopicus var. wuyiensis .In the present study ,the effect of wuyiencin on the growth and devel‐opment of Rhizoctonia solani was examined in the laboratory .On PDA plate with wuyiencin ,the colony growth of the pathogen was significantly slower than that treated with no wuyiencein ;the branches of my‐celia were markedly densified and the cytoplast excreted out from the hyphal cells .The pathogenicity of hyphae was weakened .The inhibition effect of wuyiencein became more significant as its concentration in‐creased .Both the number and the fresh weight of sclerotia were also significantly reduced at the last stage of growth .At the concentration of 50 mg/L ,the colony size of the fungus was reduced by more than 75%and the infectivity of the mycelia was lowered by 99% ;the number and weight of sclerotia were decreased , respectively ,by 67% and 61% .These results indicated that wuyiencin can suppress the growth and devel‐opment of R. solani and thus it would be potentially useful in controlling sheath blight of maize .Further assays on the efficiency of disease control on field maize crop are to be conducted .