Incidence and severity of sorghum anthracnose as influenced by sowing date in the Northern Guinea Savanna of Nigeria

Abstract

The incidence and severity of anthracnose which is caused by Colletotrichum graminicola as influenced by sowing date was investigated in 2004 and 2005 cropping seasons using two Sorghum varieties SAMSORG 4, susceptible to anthracnose and SAMSORG 41 resistant to the anthracnose pathogen, Colletotrichum graminicola. Split plot design replicated four times with sowing date as the main plots and sorghum varieties as sub-plots was used in each year. The anthracnose infection each year was dependent on natural inoculum controlled by weather, especially rainfall pattern. The result showed that sowing in early July pre-disposes the sorghum plant to higher anthracnose infection than later dates. This is particularly manifested in the combined analysis. Anthracnose incidence and severity was significantly (P<0.05) higher on SAMSORG 4 than SAMSORG 41 in both years. Accordingly, the grain yield per plot was significantly higher in SAMSORG 41 than SAMSORG 4. The interaction between sowing date and varieties was not significant in the individual years, but was found to be highly significant (P<0.01) in the combined years. Based on the results, planting dates as a measure of control to sorghum anthracnose is more meaningful when integrated with other control strategies especially the use of resistant varieties.