Antifungal Properties of Plant Extract and Density on Some Fungal Diseases and Yield of Cowpea

Abstract

Cowpea (Vigna unguiculata (L) Walp) is one of the most important food legume crops grown in many tropical and subtropical countries. An experiment was carried out during the planting seasons of 2006 and 2007 respectively, to determine the antifungal properties of plant extract and plant density on some fungal diseases and yield of Ife brown 825–124 (erect type) cowpea. Analysis of variance indicated that plant density was highly significant on leafspot disease at 6 weeks after planting (0.71, 0.82) and at 8 weeks after planting (0.74, 0.82) at 5 % probability level in 2006 and 2007, respectively. Plant extract was significant on leafspot disease severity at 4 weeks after planting (0.43, 0.51) as well as 6 weeks after planting (0.051, 0.22) in 2006 and 2007, respectively. Gongronema latifolium treated plots recorded the lowest of all the diseases and seasons investigated. No sprayed plots (control), recorded the highest leafspot disease severity (10.3, 13.3) while, G. latifolium had very high antifungal (7.7, 6.10). Vernonia amygdalina recorded the lowest severity of blight (4.3, 5.5). 50 × 100 cm recorded the highest leafspot disease severity (10.3, 15.0) as well as blight (5.7, 5.1), while 100 × 100 cm had the lowest (7.0, 6.2) in 2006 and 2007, respectively. Similarly, 50 × 100 cm recorded the highest severity of blight (5.7, 5.1) with 100 × 100 cm recording lowest (4.0, 4.6). Investigation revealed that the severity of leafspot and blight diseases had a direct relation with plants’ age. Interaction of G. latifolium and 100 × 100 cm, as well as interaction of no spray with 50 × 100 cm, recorded the lowest leafspot disease severity. Interaction of no spray with 50 × 100 cm recorded the lowest severity of leafspot disease (3.0, 4.2). Gongronema latifolium interaction with 100 × 100 cm, recorded the lowest occurrence of blight (3.0, 0.5). Similarly, interaction of V. amygdalina with 75 × 100 cm recorded the lowest severity of blight (0.3, 0.1), while that of no spray with 50 × 100 cm recorded the highest severity of blight (1.0, 1.5) in 2006 and 2007, respectively. Vernonia amygdalina interaction with spacing 50 × 100 cm recorded the highest stalk yield (119.7, 132.0). Investigation showed that closer spacing and no treatment increased the severity of the diseases on yield and performance of cowpea. The microorganisms identified with infected cowpea were Aspergillus species, Penicillium species, and Rhizoctonia solani.