Silicon (Si) is the second most abundant element in soils, and at elevated concentration levels in plant tissue Si is reported to improve plant resistance to a range of biotic and abiotic stresses. In the present study, Si solutions at 100, 300 or 500 mg L^-1 made from potassium silicate (K₂SiO₃) were applied as foliar sprays or soil drenches to pepper (Capsicum annum L.) plants, and their effects on chilli thrips (Scirtothrips dorsalis Hood) populations were studied. Data from 3 greenhouse tests showed minimal effects of Si treatments on visual leaf damage and numbers of thrips recovered from infested plants. An addition of jasmonic acid (a plant defense elicitor) with or without Si applications also did not alter the proportion of pepper leaves that sustained thrips damage. Tissue analyses showed that soil-drenched plants were able to absorb Si in roots up to ≈2.5% (w/w), but the Si was not being translocated to leaf or stem tissues at an equivalent rate. Foliar application of Si resulted in close to 0.5% (w/w) of Si in leaf tissues. Plant biomass was not affected by Si applications. We conclude that pepper plants treated with potassium silicate solutions did not accumulate to sufficient Si levels in leaf tissues to protect against thrips feeding or reproduction. To our knowledge this is the first study of Si application to pepper plants for attempts to control an insect pest.