HERBICIDE EFFECTS ON RHIZOCTONIA-SOLANI IN-VITRO AND RHIZOCTONIA FOLIAR BLIGHT OF SOYBEAN (GLYCINE-MAX)

Acifluorfen, alachlor, glufosinate, glyphosate, paraquat, and pendimet halin were evaluated for their effects on mycelial growth and scleroti a/microsclerotia production by Rhizoctonia solani AG-1 IA and IB in cu lture. All of these herbicides except glufosinate and glyphosate were evaluated for effects on severity of Rhizoctonia foliar blight of soyb ean in the field, In laboratory studies, all herbicides reduced colony radius of R. solani. Growth reductions for IB were greater than for I A in the presence of pendimethalin, alachlor, and acifluorfen, but glu fosinate reduced growth of IA more than IB, Sclerotia production by bo th isolates was prevented by paraquat, greatly reduced by glufosinate, but markedly less affected by the other herbicides tested. In field s tudies, all tested herbicides influenced severity of Rhizoctonia folia r blight when disease pressure was low, but only paraquat reduced seve rity when disease pressure was high.