ABSTRACT

The study was conducted to evaluate the effect of plant spacing and number of plants per stand on the level of infestation and population dynamics of sucking pests of okra and their natural enemies. The field experiment was carried out in the Teaching and Research Farm of Crop Science Department, University of Benin, Benin city. The experiment was laid as a Randomized Complete Block Design (RCBD) with six treatments (40cm x25cm x1, 40cm x 25cm x2, 40cm x 25cm x 3, 50cm x 25cm x 1, 50cm x 25cm x 2, 50cm x 25cm x 3) and four replications (Blocks). The data collected included: number of infested plants, number of insect pests and number of natural enemies. Data were analyzed using Analysis of Variance (ANOVA).

Pest species recorded in this study were those in the family Aphidae, Cicadellide, Thripidae, Aleyrodidae with Aphidae having the highest relative abundance (62.65%), while natural enemy species were those in the family Braconidae, Araneae, Coccinellidae with Braconidae being the most abundant with a relative abundance of 75.85%. There was no significant difference (p>0.05) in the number of infested plants, pests and natural enemy abundance. However, these variables were significantly different (p<0.001) across the WAS. The highest number of infested plants (4.46, 4.17, 4.13) was recorded at 7-9 WAS, highest pest abundance (116.21 and 156.38) was recorded at 8 and 9 WAS and highest natural enemy abundance (3.33 and 2.29) was also recorded at 8 and 9 WAS respectively. Plant spacing had no effect on the incidence and infestation of insect pests and their natural enemies on the okra field, although the age of the plant influenced the incidence of pest and natural enemies.