PLANT DEFENSE MECHANISMS IN INSECT AND MITE PEST MANAGEMENT: A REVIEW

Abstract

Plants and insects have been living together for more than 350 million years. In co- evolution, both have evolved strategies to avoid each other’s defense systems. This evolutionary arms race between plants and insects has resulted in the development of an elegant defense system in plants that has the ability to recognize the non-self-molecules or signals from damaged cells, much like the animals, and activates the plant immune response against the herbivores. Resistance can be categorized into non- preference (antixenosis), antibiosis, and tolerance, each stemming from specific plant characteristics. Morphological defenses such as trichomes, cuticle structure, and silica content provide mechanical barriers or disrupt herbivore feeding. Biochemical defenses include secondary metabolites like terpenes and phenolics that deter feeding and impair herbivore growth through anti-nutritional effects. Specific proteins such as proteinase inhibitors and chitinases further compromise insect digestion and development. Additionally, plant responses to herbivore attacks involve resource reallocation and nutritional adjustments that can deter herbivore colonization. For instance, resistant plant varieties may exhibit lower nutrient availability, leading to decreased herbivore fitness. By understanding these mechanisms, pest management strategies can be developed that utilize resistant genotypes to minimize the impact of herbivorous arthropods on agricultural yield and quality. This holistic approach integrates both morphological and biochemical traits to enhance plant defense, thereby fostering sustainable agricultural practices.