38 TRANSACTIONS OF THE ILLINOIS 



and this had 60 far disappeared after the first hard frost, as no longer to he perceptible 

 to the naked eye. In October last, in company with a party of horticulturists from 

 Michigan, Missouri, and Illinois, we again visited the (Jobden region where this root 

 disease was first found, and made a more careful search than we had done in August. 

 This time our observations were confined to trees of no particular age. A6 in our July 

 and August observations so in this there was nothing in the external appearance of the 

 trees to mark that they were diseased below ground, except the early maturity of the 

 branches and an excess of fruit buds, etc., before described. Unearthing the roots, 

 however, disclosed the fact that they were either dead, or more or less covered with 

 fungi. Although the fungi was present, it was more than possible that at this late period 

 it was in a state of rest. At what particular period of the year it is most active, is a 

 point yet to be determined, but that it is highly contagious and destructive to the roots 

 of trees seems beyond a doubt ; that it eifects the roots below ground much the same 

 as blight does the tops above, seems quite probable. In October last we requested the 

 Hon. A. M. Brown, of Villa Ridge, to make a thorough examination of his trees with 

 the view to ascertaining, if possible whether the rot on the roots of his apples was the 

 result of attacks of insects as had been stated, or of fungi ; also, if fungi could be 

 found on the roots of his pear trees. To which he replied by letter : With this letter 

 was also received several branches, leaves and roots. These were subjected to a careful 

 microscopic examination, stnd were found to be suffering from the effects of the same 

 Bpecies of fungi observed at Cobden and De Soto. We give his remarks below : 



" I was once entirely satisfied of the correctness of Dr. Walsh's opinion, that the 

 root rot with which our apple trees are affected is caused by the aphis. Recent obser- 

 vations have convinced me that he is mistaken ; and that the cause of the trouble is a 

 white papery fungus which envelopes the roots, spreading gradually but quite rapidly 

 from one to another. The aphis produces knotty excrescences upon the roots ; but 

 these not only do not kill the tree but seem not even to affect the vigor of its growth . 

 I have seen a great many instances of this. On the contrary, I have never found knots 

 or aphis on trees dead, or dying with the root rot. 



" On digging some young nursery pear trees, I found one upon a side root of which 

 the fungus had fastened. This root was dead and rotting, wholly enveloped in a white 

 substance like paper, while the filaments of the fungus could be distinctly seen spread- 

 ing rapidly upon the main root which was still green. Another tree was similarly 

 affected, only the disease had gone farther and the root was dead almost to the collar 

 of the tree. Upon neither of them was there the least sign of an insect, or of that 

 peculiar bluish mould which always indicates the presence of the aphis. * * * 



"In the bottle I send is a piece of an apple tree branch, the buds upon the spurs of 

 which were all dead. * * * * A large proportion of the buds on the fruit spurs, 

 and in some instances several inches of young growth on my Winesap apple trees, 

 died during summer ; some of them looking as if a flame had flashed up through the 

 top of the trees. It is confined almost entirely to the Winesap and affects trees widely 

 separated." 



The apple twigs referred to above, were packed with the specimens effected with 

 fungus, and were completely enveloped with it. Also some aphis packed in the same 

 bottle were dead and so covered as to appear like small balls of cotton. 



We know of no remedy lor this rotten root, but will state that pear trees may be 

 treated to salt so liberally that it would kill most other trees and plants, In view of 



