Comparative Efficacy of Black Pepper (Piper guineense) and Neem (Azadirachta indica) Seed Extracts for Managing Armyworm (Spodoptera exempta) in Maize Varieties

Abstract

African fall armyworm (AFAM), Spodoptera exempta, is a major defoliator of maize plants, causing up to 100% yield loss if control is delayed. The control of this voracious leaf feeder has relied on chemical insecticides, which have been implicated in environmental and human health hazards. There is paucity of information on sustainable management of AFAM using eco-friendly methods. Black pepper (Piper guineense) and neem (Azadirachta indica) seed extracts, each applied at 8 L per 16 L knapsack sprayer) in comparison with Cypermethrin + Dimethoate applied at 6.25 ml/L were evaluated for their efficacy in the management of AFAM in six maize varieties (DTSR-CO, WHITE DT-STR, DTSTR-SYN-2-Y, TZL-COMP3-CSDT, SYN-11-W, OBA SUPER 2), while water was used as a control. Data were collected on the number of leaf damage, percentage adult emergence, leaf area, plant height, and grain yield (kg/ha). Results showed that Cypermethrin dimethoate (CDM) was the best among the treatments. Piper guineense (PG) ranked second, while Azadirachta indica (AI) ranked third in terms of growth (leaf area) and yield increase. The least emergence of adult armyworm and the number of damaged leaves were lowest in Cypermethrin + Dimethoate treatment, while the untreated plot had the highest emergence and leaf damage in the order (CDM>AI>PG>control). The highest yield was recorded from DTSR-CO (V1). The resource-poor farmers are encouraged to cultivate improved maize variety DTSR-CO and spray Piper guineense seed extract as a sustainable alternative to synthetic insecticides in the management of fall armyworm in maize.