The response of potato late blight to the integration of selected potato cultivars, fungicides and mulch at different levels, and localities

Abstract Potato production in sub-Saharan Africa by resource-constrained farmers is challenged by late blight disease epidemics. Trials were conducted under a smallholder farming system to evaluate the effect of combining cultivars with different application levels of fungicides, mulch, and different localities for the management of potato late blight and to select effective options for the management of late blight. Four potato cultivars (Panamera, Mondial, Sababa, and Electra), two different levels of mulch (mulched and non mulched), and fungicides (sprayed and unsprayed) were laid out in randomized complete block design under five different localities (Stezi, Mbhava, Mbalenhle, Gobizembe, and Hlathikhulu) during the 2022/23 and 2023/24 seasons. Disease assessment included percentage disease severity (PDS), area under disease progress curve (AUDPC), and relative area under disease progress curve (rAUDPC). The results show that the disease severity on the cultivars Sababa and Mondial with mulch and unsprayed (SMUS, MMUS) was higher at the Hlathikhulu, Gobizembe, and Mbalenhle sites than at Stezi and Mbhava. The cultivar Mondial mulched and unsprayed (MMUS) showed high AUDPCs at the Hlathikhulu, Gobizembe, and Mbalenhle sites. The cultivar Electra mulched and sprayed (EMS) resulted in low AUDPC (196%-day) at the Mbhava site. Farmers at these locations are recommended to use the cultivar Electra and Panamara with fungicide application and mulching in Mbhava and Stezi and with no mulch in Hlathikhulu, Mbalehle, and Gobizembe to effectively manage late blight.