Measuring the impact of Collybia fusipes on the root system of oak trees

Abstract

This work describes the aetiology of Collybia fusipes root rot and the impact of the parasite on the structure of mature oak root systems. The collar roots were examined and rated for C. fusipes infection at the base of 26 Quercus robur and 20 Q. rubra trees. Trees were then felled and their root systems were up-rooted with a mechanical shovel. Number and infection status of the roots present were recorded at 40, 60 and 80 cm from the trunk base. C. fusipes drastically reduced the number of living roots. At 80 cm from the trunk base, on cylinder 3, Q. robur rated as lightly and heavily damaged had only 52 and 25 %, respectively, the fre- quency of living roots of undamaged trees; the values were 72 and 25 %, respectively, for lightly and heavily damaged Q. rubra trees. C. fusipes impacted especially the vertical roots just under the collar. ( © Inra/Elsevier, Paris.) Quercus / Collybia fusipes / root rot / incidence Rsum -Mesure de l'impact de Collybia fusipes sur le systme racinaire des chnes. Ce travail dcrit l'tiologie du pourridi Collybia fusipes et l'impact du parasite sur le systme racinaire des chnes. Le dpart des racines matresses a t examin et not pour l'infection par la collybie chez 26 Quercus robur et 20 Q. rubra. Les arbres ont ensuite t abattus et leur systme racinaire extrait avec une pelle mcanique. Le nombre de racines prsentes et leur tat sanitaire ont t dtermin 40, 60 et 80 cm du collet. La collybie diminuait fortement le nombre de racines vivantes prsentes. Les arbres gravement attaqus l'examen prcdant l'arra- chage n'avaient plus, 80 cm de la base du tronc, que 25 % du nombre de racines vivantes des arbres non attaqus. Ceux jugs fai- blement attaqus n'en avaient plus que 52 72 % selon l'espce. La destruction par le parasite touchait plus particulirement les racines verticales situes sous le tronc. (© Inra/Elsevier, Paris.) Quercus / Collybia fusipes / pourridi / impact