The impact of silicon (Si) is dependent upon crop system. In rice it minimises the damage caused by the stem borer and the planthopper, in sugarcane and wheat it minimises borers and aphids, and in cucumber and tomato it suppresses whiteflies, thrips and leaf miners. After reinforcing physical barriers, silicon activates systemic acquired resistance (SAR) and precondition plants to accelerate response to defense by jasmonic acid, salicylic acid, and ethylene signalling. This two-fold action limits the use of chemical pesticides, dealing with resistance and environmental issues. Incorporation of silicon in Integrated Pest Management (IPM) provides an effective and sustainable solution and this can be used together with biological manipulation, resistant varieties, cultural management and judicious application of insecticides. Silicon contributes to such strategies as increasing pest suppression, protecting the health of the soil, and improving the stability of yields, which means it is an important part of modern, environmentally safe agriculture.