In Tanzania, groundnut leaf rust (LR) (Puccinia arachidis) early leaf spot (ELS) (Cercospora arachidicola) and late leaf spot (LLS) (Cercosporidium personatum) diseases significantly reduce groundnut yields. This study aimed to determine the effects of location, tillage and variety on LR, ELS and LLS diseases. Location (Coastal zone (CZ), Coastal zone on station (CZ-OS), Eastern plateaux and mountain block zone (EPMBZ)), Tillage (deep and minimum), and variety (Mnanje-2009, Mangaka-2009, Naliendele-2009, Pendo-98) were the main, sub and sub-sub factors evaluated in a split-split plot experiment under Randomized Complete Block Design (RCBD) triplicated in each location. Location had significant effects (p<0.001) on incidences and severities of the three diseases. ELS incidence and severity in the CZ-OS exceeded that in the EPMBZ by 28.61 and 21.39% respectively. Difference in ELS incidence (p = 0.005) and severity (p = 0.002) between tillage techniques were observed. Highly significant differences (p < 0.001) between varieties were noted in the incidence and severity of ELS, LLS, and LR. The ELS disease incidence and severity in Pendo-98 exceeded that of Mnanje-2009 by 14.11 and 14.77% respectively. The results give clue on possible disease management measures.

Keywords: Groundnut, Leaf rust. Early leaf spot, late leaf spot, varieties, tillage