Epidemiology Of Soft Stem Rot Disease In Cowpeas Grown In Owerri, Imo State, A Rainforest Area Of Nigeria

Abstract

Epidemiology of soft stem rot disease of cowpeas grown in Owerri, Imo State, a rainforest area in Nigeria was studied. Ten cultivars of cowpea; IT86D-719, IT89K-288, VITA7, IT86D-715, IT84S-2246-4, IT90K-277-2, TVU14476, TVX3236, IT93K-452-1 and Ife-Brown were planted in the Teaching and Research Farm, Imo State University, Owerri, between May and August, 2006. Plot size of 1 x 3 m each was used with the following
planting distances, 25 x 75 cm, 25 x 25 cm, 50 x 50 cm, 50 x 75 cm, and 75 x 75 cm, arranged in a randomized complete block design. Except fertilizer application, other field maintenance practices including weeding and insecticide application were done at 4 weeks after planting. The field was rain fed throughout the duration of the experiment. Observations were made on soil temperature, relative humidity, rainfall, soil moisture,
incidence of soft stem rot disease on the cowpea seedlings, number of cowpea seedlings having symptoms of soft stem rot disease, disease lesion diameter in the affected seedlings, and seed yield. It was observed that the 25 x 25 cm and 50 x 50 cm planting distances recorded more disease-infected cowpea seedlings suggesting that
overcrowding plant population encourages spread of soft stem rot disease. Incidence of soft stem rot disease was observed on the cowpea seedlings and it was believed to have been facilitated by conducive soil temperature (24.4oC) and soil moisture recorded within the period. Soft stem rot disease attacked virtually all the cultivars; however, the number of affected seedlings was significantly lower in IT86D-715 cultivar than the other cultivars. Also cultivar IT86D-715 recorded the lowest disease lesion diameter, suggesting the cultivar's
potential as a tolerant material in the management of soft stem rot disease in cowpeas.

Journal of Agriculture and Food Sciences Vol. 5 (1) 2007: pp. 11-19