Abstract
A selective medium (SM-GGT3) for G. graminis var. tritici was developed to confirm field diagnosis of take-all [of wheat and barley]. Differentiation of G. graminis var. tritici from other common soil fungi is based on its melanin pigment formation in the presence of L-dopa. Other ingredients of the medium are potato-dextrose agar, streptomycin sulfate, dichloran, metalaxyl and Hoe 00703. A 1% silver nitrate solution was used as a surface-sterilant. There was a 32% increase in take-all isolations from irrigated wheat and barley samples using SM-GGT3 compared with using potato-dextrose agar. There was also a 49% decrease in Fusarium spp., Cochliobolus sativus and isolations of sterile mycelia using SM-GGT3.