Efficacy of Crude Extracts and Essential Oils of Selected Plants for the Management of Fall Armyworm ( Spodoptera frugiperda ) in Kenya

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), poses a serious threat to maize production in Kenya. This study aimed to assess the efficacy of crude extracts and essential oils of garlic ( Allium sativum ), red hot pepper ( Capsicum frutescens ), Sodom apple ( Solanum incanum ), and Mexican sunflower ( Tithonia diversifolia ) in controlling FAW. Sterile distilled water and Occasion Star 200SC synthetic pesticide constituted the negative and positive controls, respectively. The efficacy of the crude extracts was tested under field conditions for two cropping seasons. The pest dynamics in the field experiment were determined using the area under damage/pest curve (AUDPC). The highest pest incidence (AUDPC of 180–202) was observed in the negative control treatment, while the lowest (AUDPC of 46–49) was observed in the positive control (synthetic pesticide) treatment. Similarly, the highest damage severity (AUDPC of 100–131) was in the distilled water treatment, while the synthetic pesticide treatment recorded the lowest damage severity (AUDPC of 42). The crude extracts also significantly reduced FAW infestation and severity at variable levels compared to the control, except the Mexican sunflower which was relatively less effective. The efficacy of essential oils was tested in a laboratory bioassay against FAW third‐instar larvae where garlic and red hot pepper oils caused 100% larval mortality within 48 h, but Sodom apple and Mexican sunflower were relatively less effective. This study confirmed the efficacy of the tested botanicals for FAW management at variable levels, highlighting their potential as sustainable alternative pesticides.