EN
The plant surface, not only provides a hydrophobic barrier to reduce water loss but also presents the first line of defense against pathogenic fungi, bacteria, and herbivorous insects. Removal of the surface compounds using methanol clearly increased studied parameters of the rose-grain aphid Metopolophium dirhodum on the waxy genotype RAH 122. The largest number of rosegrain aphid was on ear at the florescence stage. Similar increase in comparison with the control plants was found for the percentage of infested plants. In addition, surface compounds from RAH 122 genotype applied on flag leaves and ears of waxy-less genotype (RAH 366) significantly decreased the number of alate forms and percentage of infested plants. Results presented here suggest that chemical compounds which occur within epicuticular waxes of the waxy genotype play an important role in its acceptance by the rose-grain aphid.