The potential of silicon in crop protection against phloem feeding and chewing insect pests - a review.

As future crop production is threatened by the increasing incidence of insect pests caused by changing climate, it is crucial to focus on searching for alternative methods of insect pest management. This review summarizes the current knowledge on the effect of silicon (Si) on the incidence, growth, development, longevity, survival, feeding efficiency, and reproduction parameters of phloem sap feeding and chewing insects of plants. While Si may negatively impact the biological parameters of both insect guilds, the effect is generally more pronounced in chewing insects, and often varies under different cultivation conditions. In addition to the direct effect of Si on insect pest performance, the potential mechanisms of Si-mediated resistance of infested plants are discussed. These involve increasing plant mechanical properties (Si-based or other organic barriers), and boosting biochemical defence responses, such as increased antioxidant activity, stimulated activity of defence enzymes, attraction of parasitoids and predators of insect pests, and synthesis of toxic and taste repelling compounds. These changes create a complex Si-induced defence system that enables infested plants to better withstand insect pest attack, ultimately reducing pest damage and improving agricultural crop yields.