Abstract

This research assessed the effect of neem leaf extract on the larval population of the fall armyworm and the level of damage, growth, and yield of maize. A Randomized Complete Block Design (RCBD) with four treatments (Control, 50 g per L, 100 g per L and 200 g per L of neem leaf extract) applied within the two seasons of 2022A and 2022B. The findings showed that a higher concentration (200 g per L) of neem leaf extract-treated maize plants registered the least leaf damage (0.15), severity (0.15), and larvae population (0.1). This effect was most attained during the 1^st season of maize production and at the earliest vegetative weeks of maize growth (3 WAP to 5 WAP, i.e., weeks after planting). The higher neem leaf extract concentration of 200 g per L produced the most significant (p < 0.001) effect on maize growth traits. A higher plant height (162.51 cm), longer leaf length (112.5 cm), wider leaf width (11.7 cm), and broader stem girth (11.91 cm) were attained under 200 g per L of neem leaf extract treated plots during the 1^st season of maize production and 11 WAP. The findings of this showed that a relatively high concentration of neem leaf extract produced a higher cob weight (200 g per L = 180.1 g) followed by 100 g per L (174.1 g), 50 g per L (140.9 g) and control (139 g). The weight was optimised during the 1^st season of maize production (163.8 g). The grain yield was higher under 200 g per L (153.7 g) of neem extract. The above findings demonstrated that a high concentration of neem leaf extract reduced fall armyworm infestation and increased maize plant growth and yield. Farmers should, therefore, be encouraged to apply 200 g per L of neem leaf extract in the management of fall armyworms and improve plant growth and yield because it contains antifeedant and insecticidal properties against the fall armyworm.

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