The effect of Septoria diseases on wheat

Abstract

The effect of natural infection of Septoria diseases, caused by Septoria tritici Rob. ex Desm. and Septoria nodoram Berk., on Gamenya wheat was investigated. In some experimental plots the diseases were partially controlled by spraying the plants with either manganous ethylene bisdithiocarbamate (Maneb) or zinc-1,2-bisdithiocarbamate (zineb) at weekly intervals, in other plots the diseases spread unchecked. Grain ripened sooner on the unsprayed plants. Yield increases of 26.3 and 29 per cent (6.4 bushels and 6 bushels an acre respectively) were obtained at two sites when spraying was commenced at the three- to five-leaf stage. When spraying was commenced at anthesis yields were not significantly increased. Bushel and kernel weights were reduced by infection and the proportion of small grains was increased. Plant height and straw yield were all greater on the sprayed plants, but the differences were not significant except for two treatments in the case of straw yield.