Phylloxera corticalis Kaltenbach, 1867
the aphids, firmly attached to the bark of one year old branches, can cause black spots of dead bark, cankerous malformations and branch dieback. The mouthparts penetrate as deep as the xylem, that locally develops brown spots. The aphids, less than a mm, are yellow, green or brown, pear-shaped (broadest anteriorly) and bear several rows of dark brown pustules. Eggs in groups on the bark and in fissures.
Quercus petraea, robur.
Barbagallo, Binazzi, Pennacchio & Pollini (2011a), Barson & Carter (1972a), Blackman & Eastop (2014), Börner & Franz (1956a), Börner & Heinze (1957a), Lampel & Meier (2003a), Redfern & Shirley (2011a)