Effect of organic amendments and fungicide application on potato late blight, bacterial wilt and yield in Cameroon

The effect of three types of organic amendments, mineral fertilizer NPK (11-11-22) + 5.5% MgO and fungicide treatment with Ridomil Gold Plus 66 WP was evaluated on late blight severity, bacterial wilt incidence and potato yield in a split plot experimental design at the research and application farm of the Faculty of Agronomy and Agricultural Sciences, University of Dschang. The aim of the study was to control the two main diseases which impede potato cultivation in Cameroon. Ridomil Gold significantly reduced (P ˂ 0.05) the severity of late blight expressed as values of standard area under disease progress curve in plots amended with compost made of garden waste (CGW) and mineral fertilizer (12.59 and 11.14%) compared to the other types of fertilization, and increased by 76% the marketable tuber yield compared to the control on the other hand. The CGW also reduced significantly (P ˂ 0.05) the intensity of bacterial wilt compared to the other types of amendments. Loss in marketable tuber yield was about 24% and 18% due to late blight and bacterial wilt in non-treated sub plots, respectively. Mineral fertilization yielded the highest marketable tuber in treated plots with 12.98 t/ha and was comparable to that of poultry manure and CGW. The study showed that the use of the fungicide Ridomil Gold Plus and CGW can be integrated in a program to control late blight and increase potato's yield, and that CGW could be associated in bacterial wilt control.