ABSTRACT
Five hot neem leaf extract concentrations (5%, 10%, 15% and 20% and 0% untreated control) were evaluated in the field, during the early and late planting seasons of 2012 to determine their efficacy at the control of some major insect pests of soybean in Asaba, Southern Nigeria. The experiments were conducted in a randomized complete block design consisting of 5 treatments replicated three times. Data on insect prevalence were subjected to simple percentage calculation while yield data were subjected to analysis of variance and treatment means separated using Duncan Multiple Range Test (DMRT) at 5% level of significance. All Hot Neem leaf extract concentrations were able to effectively reduce the population of major insect pests of the crop. Pests population reduced with increase in the concentrations of the extracts. Control plots had 51 insect pests, 5% Hot Neem Extract (HNE) had 30, 10% HNE had 26, 15% 24 while 20% HNE had 18 insects. Late season planting recorded higher insect population, with the control having 66 insects while 20% had 16 insect pests. Highest yield was obtained at 20% HNE plots which had 113 undamaged seeds (2.0t/ha), followed by 10%, with 102 undamaged seeds (2.1 t/ha), 15%, had 76 (1.2 t/ha), 5%, had 77 (1.3 t/ha) while had 100 undamaged seeds 1.4 t/ha. The yield obtained in the late season was generally low perhaps due to sowing date effects. 20% HNE which performed better than other concentration evaluated is therefore recommended for farmers in the area for the control of major insect pests of soybean. |
