This study investigates the larvicidal activities of plant extracts and tannins against wood-damaging insects. Scots pine (Pinus sylvestris), beech (Fagus orientalis), and poplar wood (Populus tremula) were subjected to larvae of Spondylis buprestoides (Coleoptera: Cerambycidae) by impregnating them with mimosa (Acacia mollissima), quebracho (Schinopsis lorentzii) and redpine bark (Pinus brutia) extracts. At the end of the 6-month experiment, the numbers of dead and live larvae as well as the mean mass losses of woods were determined. In terms of wood species, the lowest larva resistance was observed in Scots pine wood, while the highest larva resistance was achieved by beech wood. The lowest mass losses and the highest dead termite rates in all tree species were observed when the concentration of mimosa and quebracho extracts was 12%. On the other hand, the pine bark extract showed a lower larvicide effect than the other two extracts.