Leaf Surface Wax as a Possible Resistance Factor of Barley to Cereal Aphids

The role of leaf surface wax in the resistance of barley to cereal aphids, especially the dominant species Rhopalosiphum padi (L.), was studied. Aphid infestations were semilogrithmically proportional to the amount of surface wax. Furthermore, the results form hydridization experiments between a susceptible line f9-gl3-Hs-k, and a resistant line Spontaneum II, showed that the level of resistance to the aphids correlated positively with surfacce wax rather than with leas colour. Therefore, it is likely that at least part of the resistance to cereal aphids shown in some barely lines is attributable to surface wax.