This paper presents data referring to the colonization and dispersal behaviour, the life cycle of aphid species from potato cultivations for a period of three years 2005-2007, from Didactic Station Timisoara and Varfurile, Arad county, and biometrical measurements which point out the morphological caracteristics of Aphis fabae. Apterous adult have green-brown or black ovoid body and big marginal tubercles on prothorax and on abdominal segments I and VII; body length varies from 1.8 to 2.4 mm. Alatae aphid are more elongate with head and thorax shiny black; oviparous females with distinctly swollen hind tibiae and abdomen is black-green.The smallest length of the body established for aphids captured in West Zone of Romania was1,40 mm, while the biggest was 2.20 mm. The average body length was 1,83 ± 0,20 mm. Regarding the length of the head and thorax, it may be noticed that the maximum length of these parts was 0,95 mm and minimum length was 0,50 mm. The average value calculated for the length of these parts was 0,77 ± 012 mm. The minimum width of head was 0.20 mm and the maximum width of head was 0.45 mm. The average value calculated for head width was 0.32 ± 0.05 mm.As far as the thorax width is concerned, this was minimum 0.40 mm and maximum 0,80 mm. Mean thorax width was 0.61 ± 0.02 mm the minimum length of the abdomen was 0,80 mm and minimum width was 0.50 mm, the maximum length of the abdomen was 1.40 mm and the maximum width was 1 mm. The mean length of the abdomen was 1.06 ± 0.12 mm, while the average value calculated for abdomen width was 0,79 ± 0,14 mm. Aphis fabae winters in egg stage on the bark of stems or branches and plum trees, where the fundatrix. in March, give birth to apterae The average multi-annual date of flight towards the potato is 20th May. From May onwards, winged virginoparae colonize numerous secondary host plants, depositing apterous nymphs on the underside of leaves or at the tips of stems. Aphid colonies increase rapidly until mid-June, then declining progressively.Winged sexuparae appear in autumn and return to primary hosts; The rate of reproduction is positively correlated with temperature which affects all biological stages.For an estimation situations of attack can be useful to be known the most common places of colonization. Also, knowledge of potato aphid life cycle constitutes a basic element of the integrated potato pests control.

Aphis fabae, behaviour, life cycle,biometrical measurements

Presentation: oral