Efficacy of some bio-control agent formulations on scab of cowpea and groundnut late leaf spot in the Nigerian savanna

Abstract

Field experiment on fungicidal efficacy of Trichoderma harzianum, Pseudomonas fluorescens and Bacillus cereus formulations against cowpea scab and groundnut late leaf spot was conducted. The trials were conducted in 2016 and 2017 rainy seasons on two farms of the Institute for Agricultural Research located at Samaru, Zaria (11⁰ 12′ N, 07⁰ 37′ E) in the Northern Guinea savanna and Minijbir, Kano (08⁰31' E., l2⁰ 03' N) in the Sudan savanna. The formulations were applied as seed treatment, foliar spray and also incorporated into the soil by broadcasting the powdered formulations on the ridges. The experiment was laid in Randomized Complete Block Design replicated three times with five treatments which consisted of the three formulations, Funguforce (Mancozeb + Carbendazim) and control. Data were taken on plant emergence, pod yield, disease incidence and severity. Irrespective of the treatments, incidence of scab at both Samaru and Minjibir were at par. However, Funguforce application gave lowest mean scab severities of 10% and 8.5% at Minjibir and Samaru respectively in 2017. In 2016 at Samaru, P. fluorescens had the lowest incidence (50.57 %) while B. cereus had the lowest severity (14.40 %) of groundnut late leaf spot. At Minjibir however, T. harzianum recorded the lowest incidence (48.75 %) and severity (18.22 %). The incidence and severity of groundnut late leaf spot at Samaru in 2017 did not significantly vary while at Minjibir lowest incidence (9.77 %) and severity (9.73 %) were recorded on Funguforce. The microbial formulations recorded an average pod yield increase of 10 – 58 % which was comparable with that of Funguforce. The use of formulations of T. harzianum, P. fluorescens and B. cereus in the management of fungal diseases of cowpea and groundnut in the Nigerian savanna is therefore recommended.

Keywords: Genetic-crosses, RILs, Polymorphisms, Genetic-Markers, EPN