PESTICIDAL ACTIVITY OF CRUDE EXTRACTS OF ALOE SECUNDIFLORA,NICOTIANA TABACUM AND TEPROSIA VOGELII AGAINST FALL ARMYWORM (SPODOPTERA FRUGIPERDA)

Abstract

The fall armyworm (FAW),Spodoptera frugiperda (Lepidoptera: Noctuidae) is a recent invasive pest species that has successfully established across sub-Saharan Africa. Management of FAW in its native range in the Americas has led to the development of resistance to many commercial pesticides before its arrival in Africa. Synthetic pesticides are often associated with issues such as pest resistance, persistent residue, non-target toxicity, and environmental issues. Therefore, the research and development of novel, safe, and effective pesticides has become a focus in pesticide discovery. Pesticide use may therefore be ineffective for FAW control in Africa, so new and more sustainable approaches to pest management are required that can help reduce the impact of FAW pest. Pesticidal plants provide an effective and established approach to pest management in African smallholder farming and recent research has shown that their use can be cost-beneficial and sustainable. In this study, crude leave extracts of three plants aloe secundiflora, nicotiana tabacum and teprosia vogelii were evaluated against fall armyworm (spodoptera frugiperda). Two different concentrations, 30mg/L and 15mg/L were evaluated in this study against second instar FAW larvae and eggs. The results indicated that these leave extracts caused a larval and egg mortalities of different levels. On average leave extracts of aloe secundiflora, teprosia vogelii and nicotiana tabacum caused larval mortalities of 80%, 63.33% and 93.33% respectively for 30mg/L concentrations while the average larval mortalities for aloe secundiflora, teprosia vogelii and nicotiana tabacum were 26.67%, 33.33% and 80.0% respectively for the 15mg/L concentrations. The egg mortalities were relatively low compared to larval mortalities for the two concentrations used in this study. On average the leave extracts of aloe secundiflora, teprosia vogelii and nicotiana tabacum caused the egg mortalities of 16.67%, 13.33% and 43.33% respectively when 30mg/L were used while the average egg mortalities for aloe secundiflora, teprosia vogelii and nicotiana tabacum were 3.33%, 0.0% and 26.67% respectively for the 15mg/L concentrations. It follows that nicotiana tabacum showed high larval and egg mortalities for both concentrations compared to the other two leave extracts and therefore good pesticide for the control FAW larvae and eggs.