ABSTRACT:

In 2015 cropping season, SAMNUT – 14, a variety of groundnut susceptible to late leaf spot was subjected to f ive different frequencies (0, 1, 2, 3, and 4 weeks) of fungicide application. The experiment was in a Randomized Complete Block Design (RCBD) with three replications established at the Institute for Agricultural Research (IAR) Farm Samaru, Zaria. Natural infection in the field was relied upon as the source of inoculums. Stand count at emergence, and at harvest, disease severity at 60, 80 and 90 Days After Sowing (DAS) based on 1 – 9 scale, Area Under Disease Progress Curve (AUDPC), percent defoliation, pod and haulm yields were recorded. The results showed that, there was no significant difference in disease severity at 60 DAS between all the treatments. The severity recorded on plants sprayed weekly (T ) and 1 biweekly (T ) was significantly lower when compared with other treatments at 80 and 90 DAS. Unsprayed 2 plants recorded the highest AUDPC while the least was observed in plants sprayed weekly. Stand count at emergence and at harvest did not differ significantly across all the treatments. Plants sprayed weekly (T ), 1 biweekly spray (T ) and plants sprayed every three weeks (T ) recorded lower percent defoliation while T 2 4 3 0 and T with significantly higher defoliation were statistically similar. Pod and haulm yields were highest in T 1 and lowest in T . Haulm yield in T T and T were statistically similar and significantly higher than T and T . 4 1 2 3 0 4 Disease severity correlated positively and was highly significant with percent defoliation at 80 DAS and 90 DAS. Application of the fungicide at two weeks interval was considered optimum having recorded yields and disease reduction that were statistically similar with weekly and fortnightly spray. This will reduce cost and labour as well as minimize environmental pollution.