Harnessing plant silicon defenses for biological control of herbivorous insects

Silicon (Si) accumulation in plants strengthens tissues and reduces insect herbivore performance. Supplementing plants with Si can enhance the attraction of predators and parasitoids by altering the emissions of herbivore-induced plant volatiles. Herbivores feeding on Si-supplemented plants can exhibit delayed development and compromised anti-predator defenses, such as weakened immune responses. Thus, Si supplementation could potentially enhance the biological control of pest herbivores by attracting more natural enemies and increasing herbivore exposure and susceptibility to predation and parasitism. We critically examine the current understanding of the effects of plant Si defenses on interactions between herbivores and their natural enemies, highlighting key uncertainties that must be addressed to leverage the benefits of Si for the biological control of herbivorous insects.