Andricus rhyzomae (Hartig, 1843)

on Quercus, agamous generation

Andricus rhyzomae: galls on Quercus robur

Quercus robur, Elspeet, landgoed Staverden © Hans Jonkman: young, still fleshy gall

Andricus rhyzomae: galls on Quercus robur

Quercus robur, De Schipborg, Aa en Hunze © Arnold Grosscurt

Andricus rhyzomae: galls on Quercus robur

two tiny galls

gall

Galls, mostly several together, on the bark mainly near the base of a trunk. Fresh gall are semiglobular, 2-5 mm high, and have a fleshy red outer layer. After this has been eroded away, a low, woody, truncate cone remains with a radial striation on its base, and a large exit opening at its tip.

hostplants

Fagaceae, monophagous

Quercus petraea, pubescens, robur.


notes

for over more than half century is is assumed that A. rhyzomae is the agamous generation of Andricus testaceipes, but experimental proof is still being awaited. In case the synonymy might be proven, then testaceipes is the oldest, hence valid, name.
Similarly, it is broadly assumed that Andricus testaceipes var. nodifex is the sexual generation of rhyzomae; here also experimental confirmation is waiting.

synonyms

Andricus rhizomae (Schenck, 1863).

references

Buhr (1965a), Cerasa (2015a), Dauphin & Aniotsbehere (1997a), Hellrigl (2009a), Hellrigl & Bodur (2015a), Kwast (2014a), Meika (2006a), Melika, Csóka & Pujade-Villar (2000a), Redfern & Shirley (2011a), Roskam (2009a), Tomasi (2014a), Williams (2010a).