Botanical insecticides inspired by plant–herbivore chemical interactions

• Chemical defense is not the only type of defense that plants use for protection.
• Botanical pesticides are not directly comparable to synthetic pesticides.
• Lack of standards cause significant variability in the efficacy of botanical pesticides.
• Destructive extraction of plant chemicals negate most of the evolutionary successful defensive traits.
• We examine underlying assumptions that are made when developing botanical products.
• We identify practical challenges and limitations that need to be addressed.

Plants have evolved a plethora of secondary chemicals to protect themselves against herbivores and pathogens, some of which have been used historically for pest management. The extraction methods used by industry render many phytochemicals ineffective as insecticides despite their bioactivity in the natural context. In this review, we examine how plants use their secondary chemicals in nature and compare this with how they are used as insecticides to understand why the efficacy of botanical insecticides can be so variable. If the commercial production of botanical insecticides is to become a viable pest management option, factors such as production cost, resource availability, and extraction and formulation techniques need be considered alongside innovative application technologies to ensure consistent efficacy of botanical insecticides.