THE ANNUAL MEETING. 137 



from H. C. Graves & Son, Sandwich, 111., with the statement that something 

 had prevented the usual union which ordinarily takes place between the cion and 

 piece of root in certain parts of their stored grafts. Other peculiarities and 

 conditions were also given going to show that the management of the grafting, 

 packing, etc., had been such as their own abundant experience as well as the 

 common practice of the country had proved best. The work was done in mid- 

 winter and old sawdust used for packing material. The boxes were stored in a 

 frost proof cellar. 



An examination clearly showed that the cious were at the time undergoing 

 the destructive process we call blight. The case was positive enough to my 

 mind from this examination, but to make assurance doubly sure, some pear limbs 

 were afterwards inoculated with tiie bacteria laden fluid of the diseased cions, and 

 veritable blight in a previously healthy tree followed in two instances. I was 

 not surprised that more inoculations did not "take," for previous and other 

 contemporaneous experience showed the difficulty of making successful inocu- 

 lations at that season (the last of May) of the year. The disease had plainly 

 started from the cut ends of the cions, and in most of those received had not 

 yet involved the whole length. 



Having communicated these things to the nurserymen and expressed my 

 conviction that the trouble came from infection from the grafting knives, word 

 soon came that this entirely explained the facts as presented. Those kinds 

 which had been known to have suffered with ''twig blight" the preceding 

 summer were exactly the ones diseased as grafts. The workmen had now and 

 again thrown out affected twigs as they rapidly cut them up, but they knew 

 nothino; of the danger there was in smearing their knives occasionallv with 

 trial or accidental cuts of diseased pieces. Ordinarily having finished any one 

 variety the work would be cleaned up, the knives sharpened, and a fresh start 

 made upon another. Thus the contamination was not continued. With the 

 use of the same stock, stored in the same way and place, blight destroyed many 

 of one kind, none or nearly none of another. It was not possible to find out 

 whether any one variety certainly known to be free from blight during the 

 summer was at all infected in the grafting as might have been the case with 

 careful experiments tried for the purpose. 



As to remedy after a tree is infected, I cannot recommend anything but to 

 remove the diseased parts as has been so long practiced. But much care should 

 be taken to cut low enough to really accomplish the object sought. It will 

 not do to be governed by the discoloration of the leaves alone. When the 

 outer bark is smooth a characteristic discoloration early shows itself externally, 

 while the thinnest shaving from the outer bark serves to definitely locate the 

 advancing border of the blight. Care must also be taken not to further spread 

 the contagion with the pruning knife and saw. Wounds should be covered 

 with some protective material like clay, linseed oil paint, grafting wax, etc. If 

 the trees are carefully examined at least every two weeks and the infected parts 

 as carefully removed, the cure is almost positive. The disease is of the bark 

 rather than of the wood, and of the bark it is the outer, living cellular layer 

 which most suffers. Sometimes this thin stratum may be diseased more or less 

 throughout most of the tree, while by a casual observer the tree would be ac- 

 counted perfectly healthy. Sometimes the whole thickness of the living bark, 

 especially in patches on the trunk, may be affected, though the cambium may 

 continue healthy, as is sometimes shown by a new layer of bark formed under 

 the old. Quite often the disease is checked or permanently stopped by the 



