Effect of sowing date and fungicide frequencies for management of chocolate spot (Botrytis fabae Sard.) of Faba bean (Vicia faba L.) in Southern Ethiopia
Abstract
M. Kebede* and M. Getahun
Faba bean (Vicia faba L.) is one of the major pulse crops grown in Ethiopia and many countries. However, the production and productivity of the crop is affected by several biotic and abiotic factors. Among these, chocolate spot caused by (Botrytis fabae Sard) is one of the most important destructive diseases hampering faba bean production. This work was carried out during the 2015 and 2016 cropping seasons to determinate the effect of sowing date and fungicide frequencies for management of chocolate spot of faba bean in potential growing areas of Silte and Hadya zone, southern Ethiopia. The treatments comprised three sowing date intervals and three fungicide frequencies. Unsprayed controls were also included to allow maximum disease severity for comparison. The trial was arranged in randomized completely block design (RCBD) in factorial arrangement with three replications. The trials clearly determined the appropriate sowing date and fungicide frequency for management of the disease. The statistical analysis showed significant differences (p<0.05) among the treatments for most of the parameters tested. The result of the study revealed that the maximum terminal severity of 64.7% at Alicho and 63.4% at Analimo were recorded on unsprayed plots of 2nd and 3rd sowing date respectively. The disease resulted in high grain yield loss of 52.1% at Alicho and 51.4% at Analimo on unsprayed plot of last sowing date. The maximum grain yield of 3649.4 kgha-1 at Alicho and 3557.1 kgha-1 at Analimo were obtained due to the interaction effect first sowing date and three-time application of fungicide. There was a significant strong negative correlation between disease incidence, severity and AUDPC to that of grain yield with correlation coefficient ranging from, r=-0.84** to r=-0.96**. The present research finding revealed that the combination use of first sowing (early sowing) and three-time application of Mancozeb 80% WP at the company rate of 2.5 kgha-1 can be recommended as the appropriate management option against chocolate spot in an area. However, further study should be necessary to come up with more inclusive recommendation and thereby increase production and productivity of faba bean in the region and elsewhere with similar agro ecological settings.