Disease response of two potato varieties to time of weeding and fertilizer rates in Sudan savannah of Nigeria

Abstract

Field trials were conducted under irrigation, at Usmanu Danfodiyo University Teaching and Research Fadama Farm at Kwalkwalawa village, Sokoto during the 2001/02 and 2000/03 dry seasons. The objective was to determine the disease response of two potato varieties on time of wedding and fertilizer rates. The treatments consisted of two potato varieties (RB68-18 and RC 7716-17), four N.P.K. (20:10:10) fertilizer rates (0,80,160 and 240kg/ha) and three weeding regimes (zero-weeding, weeding at 4 weeks after planting and weeding at 6 weeks after planting) which were laid out in a split plot design replicated three times. Variety and fertilizer rate were allocated to the main plot while weeding regime was allocated to the subplots. Results revealed that Bacterial wilt disease was not influenced by all the treatments at all the stages considered. Significantly (P<0.05) highest percentage of Early blight disease was recorded on plots that were neither weeded nor applied any fertilizer (2.25 and 2.17% respectively). Lowest percentage of rotted potato tubers was obtained at zero fertilizer rate. The variety BR 68 – 18 produced significantly lowest rotted tubers (10.3%) compared with variety RC7716 – 17(25.96%). For common scab infection however, variety RC7716-17 recorded the lowest in both trials. The research concluded by recommending application of fertilizer at 80 kg/ha and weeding at 4WAP and improved disease control measures, particularly those that involve exclusion principles, like seed treatment and spray against the vectors.