EGG DISTRIBUTION AND SURVIVAL OF CINARA-PILICORNIS (HARTIG) (HOM, LACHNIDAE) ON DAMAGED AND UNDAMAGED NORWAY SPRUCE (PICEA-ABIES) (L) KARST

The spruce shoot aphid (C. pilicornis) (Hartig) lives on Norway spruce (P. abies (L.) Karst.) and deposits its overwintering eggs on current year needles. Ovipara density and the distribution of their eggs on t rees at two different sites of the Fichtelgebirge (north-east of Bavar ia), with host trees showing either heavy symptoms of needle-yellowing (Oberwarmensteinach) or look green and healthy (Waldstein) is investi gated. In addition, winter mortality of eggs and egg development until birth of the fundatrices is followed. Host plant quality does not see m to influence the proportion of eggs surviving to spring. Also, the b iomass of developing first instar larvae of the fundatrices was indepe ndent of the degree of needle yellowing. However, significantly more e ggs/shoot and eggs/twig were found on hosts without growth disturbance which is due to a higher ovipara density and a higher fecundity of in dividual ovipara. Damaged or stressed trees do not seem to be better h osts for C. pilicornis. A significant correlation was found between th e biomass of first instar larvae of fundatrices and the time of egg ha tching. The high phenotypic plasticity of C. pilicornis on good qualit y plants is discussed and potential implications for forestry are asse ssed.