Bumps on trunks

[David R. Hershey]

Large bumps on trunks are often caused by crown gall bacteria 
(Agrobacterium tumefaciens). Plants in the rose family are most susceptible
but it attacks many other species.

******************************************************************
David R. Hershey
					
Snail mail: 6700 Belcrest Road #112, Hyattsville, MD 20782-1340

Adjunct Professor, Biology/Horticulture Department
Prince George's Community College, Largo, MD 20772-2199

Email: dh321 at pgstumail.pg.cc.md.us
*******************************************************************


On 30 Sep 1996, Gunnar Fridborg wrote:

> Hi tree lovers!
> 
> Big bumps on the lower parts of  trunks are  frequent in some aereas, for
> instance on oaks. To my students I use to say that such a bump consists of
> wound tissue developed where a  branch was broken or sawed. Nor I or my
> student are fully satisfied with that explanation but I have no other. Have
> you?
> 
> Thanks
> 
> -------------------------------------------------------------------
> Gunnar Fridborg
> Associate Prof, Lecturer, Director      Docent, Univ lektor, Studierektor
> of Education
> Department of Physiological Botany      Inst for fysiologisk botanik
> Uppsala University                      Uppsala universitet
> Villav=E6gen 6  S 752 36 Uppsala Sweden   Villav=E6gen 6  752 36 Uppsala
> Phone +46 18 182820                     Tel 018 182820
> =46ax   +46 18 559885                     Fax 018 559885
> E-mail  Gunnar.Fridborg at fysbot.uu.se
> --------------------------------------------------------------------
> 
> 
>