GALLS CAUSED BY FUNGI 
123 
In June, 1911, the Board of Agriculture and Fisheries 
issued a leaflet (No. 245) concerning the crown-galls on 
Plum, Rose, raspberry, and logan-berry recently sent to 
Kew, and similar galls in every stage of development on 
the roots of the Paris Daisy {Chrysanthemum frutescens, L.). 
“The galls are usually formed just under ground on the 
collar or root, and so escape observation. They commence 
growth as minute wart-like bodies ; growth is rapid, and 
the surface of the gall becomes coarsely warted and dark 
coloured, and varies in size from 2 to 3 inches in 
diameter to that of a football, or even larger. The galls 
usually decay at the end of one season’s growth, and leave 
an open wound, which penetrates for some distance into the 
wood. The following season gall growth commences round 
the edge of the wound formed in the previous season. 
These galls perish in turn, and the process is repeated each 
season, resulting in a large, deep wound. When two or 
three such wounds are present on different sides of the 
collar, the tree usually breaks off at the wounded part. 
“ Two distinct organisms have been found to occur in the 
tissues of the galls, but a bacterium, Bacillus tumefaciens , 
has been proved, in America, to be the primary cause of the 
disease.” 
For remedial and preventive measures the pamphlet 
should be consulted. Full particulars concerning the 
fungus pests mentioned in this chapter may be found in 
Massee’s “Textbook of Plant Diseases” and the various 
leaflets issued by the Board of Agriculture and Fisheries. 
