462 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



There have been great differences ot 

 opinion regarding the amount of damage 

 resulting in the orchard from planting 

 diseased trees. Some writers have claim- 

 ed that affected trees never become profit- 

 able and that great losses occur among 

 them. Undoubtedly the effects of more 

 serious maladies such as root rot which 

 may affect galled trees, have often been 

 confused with crown gall injury. Care- 

 ful investigation shows that the effects 

 of the disease in orchards are not as seri- 

 ous as some have supposed. Loss does 

 frequently occur, however, since galled 

 trees are more liable to die the first year 

 or two in the orchard than are unaffected 

 trees. Many trees, on the other hand, 

 seem to recover completely and grow into 

 vigorous and profitable maturity. The 

 writer has seen cases, however, where 

 trees of bearing age were evidently stunt- 

 ed and unprofitable because of the growth 

 of hairy root or crown gall on the roots. 

 The orchardist is urged, therefore, to set 

 the healthiest trees obtainable. If for 

 any reason it is deemed advisable to set 

 out diseased trees, galls and hairy root 

 should not be cut out as the effect of the 

 crown gall is likely to be less injurious 

 than the results of such wounds made 

 when the tree is young. If an old tree 

 affected with crown gall appears healthy 

 and is profitable, it is not recommended to 

 remove the tree or to cut off the galls, 

 since there is little danger of the disease 

 spreading seriously in an orchard and 

 cutting out frequently results in greater 



damage to the tree than the presence of 

 the tumor. If, however, a tree is rendered 

 unprofitable, it had better be removed, 

 although the grower might try thorough 

 cutting out of the galls and disinfecting 

 and painting over of the wounds, a meth- 

 od which is rarely a complete success as 

 it is ordinarily practiced. In districts 

 where fire blight is prevalent, it has been 

 found that crown galls afford peculiarly 

 favorable points of entrance for the bac- 

 teria causing the blight, much damage 

 having frequently resulted in this way. 

 In such districts, therefore, it is recom- 

 mended to remove a strip of bark an inch 

 wide around the base of the gall and then 

 cut out the entire gall, being sure to re- 

 move every portion of it. The exposed 

 surface should then be washed with a 

 solution of corrosive sublimate. 



Stone Fruits 



Ot the stone fruits the peach is most 

 frequently mentioned as seriously affected 

 by crown gall. It would appear that 

 crown gall has usually a very much more 

 disastrous effect on peach trees than 

 upon apples. The root system is often so 

 affected that the diseased tree cannot es- 

 tablish itself in the orchard, or, suc- 

 ceeding in that, fails to become vigorous 

 and profitable. Never plant a galled tree. 

 Prunes are known to be affected with 

 the disease, but most of the cases on trees 

 grafted on peach roots. Cherries and 

 other stone fruits are also subject to at- 

 tack. Cases of recovery from crown gall 



Fig. 3. Crown Galls on a Loganberi-.v Stalk. 



