Current options for improving leafspot disease resistance and yield of groundnut in an Ultisols

Abstract

A two-season experiment was conducted in 2003 and 2004 on the current options for improving the severity of leafspot disease and yield of groundnut in the Ultisiols of Imo State. Four plant densities were variously combined with three organic manures at four replications with zero as the control in 2003 and 2004, respectively. The result showed that organic manure significantly reduced the severity of leafspot disease (P<0.05; 0.52 and 0.66). It also significantly influence stalk yield (tha−1) and yield (tha−1) 11.00; 12.86; 14.05; 15.82 in 2003 and 2004, respectively. Planting density 250 000 plants/ha, recorded the least leafspot severity 0.48; 0.55 while 444 444 plants/ha recorded the highest leafspot severity of 1.00 and 1.25 in 2003 and 2004. Fowl droppings significantly reduced the severity of leafspot disease 0.38; 0.50 in comparison with cow dung 0.66; 0.88 which were lower in 2003 and 2004, respectively. However, control (O-treatment) recorded the highest severity of leafspot disease 0.92; 1.30 in 2003 and 2004, respectively. The same trends were observed in stalk yield with fowl dropping recording the highest yield 14.28, 15.06 followed by cow dung 13.25; 14.00 while O-treatment (control) recorded the lowest 11.96; 12.50 in 2003 and 2004, respectively. But 250 000 plants/ha produced the lower stalk yield (tha−1) 13.64; 14.40, but the highest seed yield 11.35; 12.00, while 444 444 plants/ha had the highest stalk yield 16.28; 17.10 but lower seed yield 11.26; 11.88 tha−1 in 2003 and 2004, respectively. Also, the severity of leafspot disease increases with plant age in all treatments and all seasons. Edaphic conditions of the study site especially concerning soil reaction influenced the incidence and severity of leafspot disease on groundnut. The succulence of groundnut leaves promoted leafspot disease attack.