Evaluation of plant extracts for the control of groundnut leaf spot

Abstract

Benomyl, mahogany bark extract (MBE) and neem leaf extract (NLE) were evaluated under field conditions at Minna (98 410 N, 68310E, 400 m above sea level), Nigeria during the 2002 – 2003 and 2003 – 2004 wet seasons for control of late leaf spot [Phaeoisariopsis personata (Berk & Curt) V. Arx] of groundnut. Benomyl was sprayed thrice at the rate of 0.6 kg a.i./ha in 400 litres of water, while each plant extract was applied six times, at a concentration of 25% (w/v). All the treatments were effective against the pathogens. On average, benomyl,MBE and NLE reduced leaf spot severity by 66.9, 54.1 and 49.1%, respectively, compared with the untreated control. Haulm yield was 22.4, 18.2 and 14.9% higher in the plots treated with benomyl, MBE and NLE, respectively, compared with the untreated control. Benomyl,MBE and NLE increased pod yield by 37.3, 31.6, and 25.2%, respectively, compared with the untreated control.