Plant secondary metabolites as an alternative in pest management. I: Background, research approaches and trends

In the search for alternative solutions to plant health problems, the interest in plants and their chemo-biodiversity as a source of bioactive secondary metabolites has increased. Among the topics considered in this review are the general aspects and approaches to study plant secondary metabolites from the pest management perspective, including the progress achieved in the discovery process of new potential biopesticides. A background and the present situation of the development and use of these metabolites in pest management are covered emphasizing their perspectives and challenges. For a successful research and development process leading to a commercial product, a wide range of criteria (biological, environmental, toxicological, regulatory, and commercial) must be satisfied from the beginning. Among the major challenges to be faced by the candidate products to reach the market are the sustainable use of raw materials, the standardization of chemically complex extracts, and the regulatory requirements and approval. The unique set of secondary metabolites produced by plants may play an important role in a sustainable pest management as new products directly, as novel chemical frameworks for synthesis and/or for identifying original modes of action. The potential of plants and their secondary metabolites for plant health could be used in different strategies: employing the whole plant, crop residues and part of plants, and using plant chemicals and extracts in integrated or ecological pest management acting directly on the target pest or inducing resistance.