Mapping rhizoctonia patch in consecutive cereal crops in Western Australia

Abstract

Rhizoctonia patches in a field were mapped during consecutive seasons of cropping with wheat, oats or barley sown directly without tillage into the previous season's stubble. Distribution, size, shape and number of patches varied considerably between seasons. Less than a quarter of patches were circular and the others tended to be elongated parallel to seed‐rows. Barley was most severely affected, followed by wheat and then oats. It is proposed that changes in patch distribution, configuration and number between seasons is due to shifts in a balance of suppressive or conducive soil factors interacting with Rhizoctonia solani inoculum.