1872 T}ie Western Povvologist and Gardener. 119 



by the direct rays of. the sun destroying the vitality of the sap." If these theories were 

 correct, then there should exist some unmistakable relation between cold, heat, and the 

 blight, as cause and effect; therefore, the more severe they were the worse the disease. 

 Consequently, the more tender the trees, the more they would be injured, and the worse 

 they would be blighted ; for the Doctor says, "the deeper the freezing has gone, the more 

 fatal the disease." If his theories were true, then blight would be governed by extremes 

 of cold and heat, and it would be much worse in Western Kannas, Nebranka, and Minnesota, 

 where these extremes are tlie greatest, than it would be in New Jersey, Delaware, and Mary- 

 land, where they are much less. But this is not the case, for it scarcely exists in the 

 former, while it is very destructive in the latter. 



It is singular, according to his theories, that Tallman's Sweet and Keswick Codlin, 

 which withstand such hard freezing without injury, should blight so severely, while Lit- 

 tageskee, which is so tender, should entirely escape it. But it is still more singular that 

 the various crab apples, which are so perfectly hardy in almost any climate, and mature 

 their wood so early and perfectly, should be the most subject to blight of any. The most 

 severe and sudden changes to cold we ever experienced, and which done the greatest 

 injury, occurred in the falls of 1858 and 1863. In both instances it killed all the peach 

 buds, and very much injured the fruit trees. We had over 40,000 apple seedlings killed, 

 and nearly all kinds of grape vines were killed to the ground. The nursery stock was 

 severel}' injured, and the inner bark of fruit trees very much discolored. Yet we grafted 

 from those injured trees both seasons more than 300,000 grafts, and never had better suc- 

 cess, and not a single tree blighted either season, nor up to 1866, but since that time we 

 have had more or less of it. 



But the most conclusive proof that freezing has nothing to do with it is, that cions 

 not frozen at all, will, when grafted, blight when put upon perfectly hardy trees not sub- 

 ject to the disease in May and June, before hot weather, and that seedlings will some- 

 times blight the first season from the seed. We fear the Doctor has confounded blight 

 with winter kiUing, which often occurs with tender trees by severe freezing, but is as dif- 

 ferent from what is usually called blight as his sun-scald. This will no doubt account for 

 all of his apparent facts which he puts so much stress upon, and which corresponds with 

 our observations at the principal periods mentioned. We maj' not be able to fully show 

 how blight is produced, but that it does exist under certain conditions favorable to fun- 

 goid diseases, will not be denied. Some eight years ago in the Horticulturist, we pointed 

 out the distinction between </rape-ro< and raiW«a!, and showed that the"ro<" was due to 

 excessive moisture, and mildew to excessive dryness. Experiments with the mildew showed 

 sulphur a remedy both in this country and in Europe, but it did not cure the rot, show- 

 ing them to be different maladies. Recently Mr. Thomas Taylor, who is conducting the 

 microscopic investigations into fungoid diseases at the Department of Agriculture, pre- 

 sented us plates' of the observations made, and in Moore's Rural New Yorker we find the 

 following conclusions, which confirm our theory : 



" On the suggestion of Mr. Sanders, the experiment of keeping the grapery of the 

 Department very dry for a few days, resulted in so rapid a development of the European 

 mildew {Erysiphe Tuckeri) that he obtained for the first time, either in Europe or Amer- 

 ica, the perfectly ripened conceptacle, or fruit of that variety. It follows that the Euro- 

 pean mildew is developed by dry heat, while the American mildew (another fungus) 

 requires moist heat." " On the wood of last year's growth he finds the mycelium, or cob- 

 web like branches of this pe.st, capable of resuming active growth when subjected to 

 warmth and moisture." " There is also an American variety which Mr. Taylor has 

 found the conceptacles," produced " under the same conditions as the European." 



Here we have demonstrated facts that under certain conditions of dryness or moisture 

 these various fungoid diseases are developed, and rapidly spread. Whether the dryness 

 or the moisture is the cause of the disease or the fungus, we do not now pretend to deter- 

 mine, but that it requires these conditions before it spreads must be admitted. This cor- 

 responds exactly with our former views, and also with our more recent observations ; for 



