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 (9° 41′ N, 6°31′E, 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.

Keywords:

• Benomyl
• plant extracts
• leaf spot