DIVISION OF GARDENS AND GROUNDS. 43 



mended. After experiments had shown that these prescriptions were 

 of no vahie, then electricity was assumed as the cause of blights aud 

 rots, which was equivalent to an admission that both the cause and 

 remedy were alike unknown. About twenty years ago it was suggested 

 that tiie active cause of decomposition in the case of pear aud api)lo 

 tree blight was of a fungoid character, and applications known to be 

 fatal to fungi were then recommended and used with apparently good 

 elfects. 



The opinion has been advanced, and in some instances the advice has 

 unfortunately been followed, that when a tree first shows evidence of 

 having a blighted branch, it should be rooted out as being beyond re- 

 covery. This is not good advice, for it is well known that trees, whicb 

 have been so badly affected as to necessitate the cutting back of every 

 branch close to the body of the trees, have again branched out and in 

 time have borne good crops of fruit, and are no more liable to blight 

 afterwards than any other tree which has never been attacked. Even 

 where trees have been so badly affected that the entire stem had to bo 

 cut over close to the surface of the ground, young shoots have come up 

 and have speedily grown into sound, healthy fruit-bearing trees.' 



The latest discovery regarding pear and apple tree blight indicates 

 that it is caused by bacteria, a very low form of vegetable growth, classi- 

 fied much lower in the scale than fungi. Bacteria, it is stated, locate 

 themselves on tender portions of the twigs, such as the extreme points 

 of growing shoots, or in the opening flowers, or, it may be, in very soft 

 and moist portions of the bark, and, from these spots favorable to their 

 attachment, they enter into the shoots, and from them to the larger 

 branches and follow on under the bark. 



The experiments upon which the theory of bacteria, as the cause of 

 blight, is based, are of much interest, and seemingly leave but little 

 room to doubt its accuracy. 



The deductions which micrologists form from the observations made 

 on bacteria, lead them to the conclusion that external applications can 

 be of no value by way of prevention from blight, and that it is futile to 

 endeavor to cure a blighted shoot, and that the only resource is to cut 

 out a dead or diseased branch and remove it from the orchard. 



Practical orchard ists will possibly have some opinions upon this point 

 which may differ somewhat from the above conclusions. They will 

 indorse the advice that it is useless to try to resuscitate a dead limb 

 of a tree, and that the further advice to prune out dead branches is 

 supremely superfluous; but the mere fact that the blight is caused by 

 bacteria does not militate against methods which have been considered 

 valuable when the disease was supposed to be of a fungoid nature. The 

 ])ractice of coating trees, as far as can be done conveniently, with a 

 lime wash containing sulphur has been frequently indorsed as a wise, 

 precaution by those who have tried it. It is asserted that no iiart of 

 a pear tree covered with this wash has ever been attacked by blight. 

 On the other hand, the opinion is held by those who have studied the 

 bacteria, that they enter into the tree only by the tender buds, or at 

 very soft, moist, succulent parts, and that they never attack the bark 

 of the branches or trunk; hence, it is argued, lime covering of these 

 parts cannot have any effect whatever in preventing bacteria from in- 

 juring the tree and causing blight. 



This may seem sufficiently conclusive from a certain standpoint ; at 

 the same time it is not unusual to find blight on the stem or trunk of a 

 tree where there are no tender buds or flowers for bacteria to enter, and 

 yet they have found some means of entrance ; but it is proved so far 



