16 CAUSE AND NATURE OF CROWN-GALL 



HISTORY OF SOME OF THE TREES TREATED WITH BORDEAUX 



MIXTURE. 



No. ii. This specimen was a large and apparently thrifty 

 tree when examined, February 26, iSq6. However, when the 

 crown was exposed one gall two inches in diameter and nearly 

 spherical was found on the northwest side of the crown, about 

 six inches beneath the surface. Several small galls were also 

 found in inaccessible places beneath the larger roots. The ex- 

 posed gall was cut away, care being taken to remove it in its 

 entirety. The other galls were only partially removed. The 

 wounds made in removing the galls were liberally treated with 

 the fungicide and later coated with tar. 



When examined the latter part of April it was found that 

 the scar caused by the removal of the gall from the crown had 

 dried over, and a healthy growth of callus tissue had begun to 

 inclose the wound. The deeper-seated galls had begun to form 

 a quantity of rapidly growing diseased tissue at the point of 

 union of the old galls to the roots. In September of the same 

 vear the callus tissue previously noted had continued to de- 

 velop until the wound was nearly covered. However, at one 

 side on the callus a young gall was rapidly forming. This 

 o-all could not have been more than three or four weeks old, 

 and probably was the result of reinfection of the young tissue of 

 the callus by the parasite in the soil. The deeper-seated galls 

 had continued to grow during the summer and were larger 

 than the ones removed in February. The tree was badly dis- 

 eased and worthless when cut down, in the fall of 1899. 



Xo. 46. This tree (Fig. i) had a number of large galls 

 almost completely surrounding the bole a few inches below the 

 surface, the rapid development of which during the previous 

 year had so checked the growth that practically no new wood 

 had formed. The tree was in abundant bloom, as if making a 

 great effort to fruit before succumbing to the destructive action 

 of the gall. A large gall on the north side penetrated to the 

 heart of the tree, and less than one and one-half inches of the 

 entire circumference showed healthy growth. The galls, so far 

 a-- possible, were cut away and the fungicide and tar applied. 



