Phytochemical activity and role of botanical pesticides in pest management for sustainable agricultural crop production

Increased demand for food to feed the ever-growing population led to development and adoption of synthetic chemicals as a quick and effective strategy of managing crop pests and diseases. However, overreliance on synthetic pesticides is discouraged due to their detrimental effects on human health, the environment, and development of resistant pest and pathogen strains. This, coupled with increasing demand for organically produced foods, stimulated search for alternative approaches and botanical pesticides are particularly gaining importance. Botanical pesticides are efficacious in managing different crop pests, inexpensive, easily biodegraded, have varied modes of action, their sources are easily available and have low toxicity to non-target organisms. Their varied modes of action are attributed to the phytochemical composition in different plants. Therefore, they can be incorporated into integrated pest management systems and contribute to sustainable agricultural production. Nevertheless, botanical pesticides have not been fully adopted due to challenges in formulation and commercialization which are attributed to lack of chemical data and positive controls. Many publications have featured botanical pesticides with skewed interest towards management of insect pests. This review brings together information regarding botanical pesticides, their phytochemical composition and mechanisms of action against pests of importance in agricultural production. The paper also presents chemistry data of selected botanical pesticides, their biodegradation, role in integrated pest management and the challenges facing their adoption and utilization for sustainable crop pest management. (C) 2019 Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.