Evaluation of crude aqueous leaf extracts of Tephrosia vogelii, Azadirachta indica and Cissus quadrangularis on the control of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize (Zea mays)

Abstract

Fall armyworm (S. frugiperda) is one of the major pests causing significant damage to maize leading to quality and yield losses for maize producers especially the smallholder farmers thereby threatening food security. The response to the pest mainly relies on synthetic pesticides which are often unaffordable to small-scale farmers. Excessive use of synthetic insecticides has raised concerns regarding environmental pollution, pest resistance and health hazards, hence the need to explore sustainable alternative pest management options. This study evaluated the effectiveness of locally available botanicals fish bean (T. vogelii), neem (A. indica) and veldt grape (C. quadrangularis) in the control of fall armyworm. The experiment was laid out in a Randomised Complete Block Design (RCBD) with five treatments (three botanicals, a positive and negative control) replicated four times. Data was analysed using the GenStat version 18 using Least Significant Difference (LSD) at 5% significance level. The results showed significant differences (p<0.001) among treatments in pest incidence, leaf damage, plant height and grain yield. The positive control (Lambda-Cyhalothrin) was consistent and outperformed all the other treatments as it had the least pest incidence of 22.5%, 30%, 40%, 50% at 5, 6, 7and 8 weeks respectively while the untreated control recorded highest pest incidence of 52.5%, 65%, 72.5% and 80% during same sampling periods. The untreated control recorded the highest leaf damage scores of 3.75, 5.25, 6.25 and 7 from week 5 to 8 respectively. Lambda-Cyhalothrin and A. indica produced taller plants and higher grain yields compared to other treatments. The study concluded that botanical extracts possess insecticidal properties capable of reducing fall armyworm incidence and leaf damage while improving maize growth and yield. Among the botanicals evaluated A. indica was the most effective, followed by T. vogelii, whereas C. quadrangularis showed comparatively lower effectiveness. These results suggest that A. indica has strong potential as an effective botanical pesticide for sustainable fall armyworm management, improved maize yields, and environmental protection in Zimbabwe. Fall armyworm