Importance of epicuticular wax cover for plant-insect interactions: experiment with cereal aphids

The epicuticular wax is the contact point between plants and the environment and plays a crucial role in mediating biotic and abiotic interactions. The associations between the content of epicuticular waxes, on surface plants of winter triticale with their acceptance by the grain aphid Sitobion avenae and bird cherry -oat aphid Rhopalosiphum padi were studied. In general, waxy genotype DED 1137 of winter triticale was less accepted by the cereal aphids than the wax less one (RAH 366). The waxy genotype decreased density of cereal aphids, prolonged maturity and decreased fecundity. Moreover, the comparison of abundance, development and fecundity of the aphid species on the triticale genotypes proved that tested genotypes differed in susceptibility to Sitobion avenae and Rhopalosiphum padi. The importance of the epicuticular wax compounds in the acceptance of plants by the aphids is discussed. The results indicated that aphids fed on waxy plants showed longer time of the prereproductive period and much lower total fecundity. Furthermore, waxy genotype reduced value of the cumulative aphid index and percentage of infested plants.