44 



TRANSACTIONS OF THE ILLINOIS 



less filled with fibres of dead wood, will rot terribly year after year, whenever seasons fa- 

 vorable to rot occur, standing side by side with the young and sound vines which escape, 

 and why ? Because the one has the nidus of these sporules within itself while the other 

 has not. 



There are, as I have intimated, various forms of grape rot or blight so called, but did 

 any one ever know or read or hear of our destructive American Grape rot, in climates 

 like Italy or California, where there is no frost to produce dead or rotten filaments of 

 wood in roots or branches? True, in isolated cases, these rotten fibres in the roots may 

 be produced by other causes, such as foolish summer pruning, wounds or insects, or ex- 

 tremely wet and uncongenial soil ; but the great cause here is unquestionably cold weath- 

 er, and with my present view I would not give half price for a Catawba vineyard that 

 had ever in one single instance been left uncovered and exposed to killing winter frosts. 

 I should feel quite sure that when a season favorable to blight came, even if it was not 

 for ten years after such an exposure, those grapes would rot. True, unsoundness from 

 any other causes which may have produced it, would operate just as badly. In investi- 

 gating this subject some ten years ago, I carefully took up some Catawba and Isabella 

 vines, the oldest 1 then had (and some ten or fifteen years old at least) which were much 

 addicted to rotting, and which I knew had been several times frozen down. I found all 

 their main roots filled with filaments of rotten wood ; notatruly sound root amongthem. 

 I cut two or three of the worst ones to pieces to examine them ; for the rest I made an 

 artificial soil, composed of the very best materials I could command for the Grape, and 

 set them out a^ain. They grew finely, but they have never got over their fatal habit of 

 rotting, whenever a rotting season comes round, even though my younger and sounder 

 vines of the same sort escape. The old nidus of Cryptogams or fungi is there still, all 

 ready to swarm, and flare up, and destroy, whenever an inviting season occurs. 



III. All must have noticed also, that in years of blight the highest sboots, or those 

 farthest removed from the nidus, are affected least of all. Indeed, on these old vines 

 above mentioned, some of the extreme branches often wholly escape and produce their 

 fruit, showing that the disease progresses from the root toward the top, and is generally 

 most efficient nearest to the nidus or primal cause, and that the fruit is most safe on the 

 more remote and soundest branches, wholly of recent growth and of course of greatest vig- 

 or. I will not here dilate on the importance of covering every vine not known to be per- 

 fectly hardy, every year, without one single failure, which spoils the whole thing of 

 course, for when you once get a nidus of rotten fibres in your grape roots they can 

 never be got rid of. 



In the case of the pear tree blight, the nidus is evidently the patch of rotten or dead 

 bark on the trunk of the tree, or it may first be in the wood or the roots, or in all these. 

 But the only place where you can get at it, is the spots on the bark and limbs of the 

 tree ; and probably removing that, will do no good, if not clone before the sap begins to 

 flow in the spring ; for after that the sporules would be diffused over every rotten or de- 

 fective atom of wood or bark in the whole top ; ready to attack the tender living tis- 

 sues the first moment the season favored their growth and power. On this theory Dr. 

 Schroeder's layering of vines and Dr. Hull's root pruning come fully into play ; the one 

 keeps the grape roots at all times new and sound, the other checks the annual growth 

 of the pear tree, and prevents that immaturity, plethora and engorgement of sap about 

 the forks and trunk of the tree, which seems to be one of the conditions which furnish 

 the sporules on the pear-tree the means of getting hold of its living tissues. But under 



