DATA ON LIFE-CYCLE OF RHOPALOSIPHUM-PADI (L) (HOM, APHIDIDAE) ON CEREAL CROPS IN CENTRAL ITALY

Field observations carried out in 1987-1988 in Central Italy (Latium, Castelporziano) on Rhopalosiphum padi (L.) life-cycle in relation to t he crop stages of two cultivated cereal hosts (wheat and triticale) ar e presented and discussed. The sampled populations seemed to develop a monoic homotopic anholocycle. Only colonies of exules (apterous and w inged), always located on the epigeic part of the plant, were found du ring the study. No sexuate forms and no overwintering root-living spec imens were recorded. Probable relation with plant morphology and host localization is also discussed. The late sowing date as a stress facto r in the development of the sampled aphid populations is suggested.