MICHIGAN STATE POMOLOQICAL SOCIETY. 475- 



and written about the cause. We do know that in severe weather 

 the interior, or heart-wood, of trees will often be destroyed, while 

 the external layer of wood will escape injury; and that seasons 

 following this, the sap does not ascend freely into the damaged 

 structure, and that weak sprouts appear on the lower portions 

 of the branches, and also that the whole circulation is so ener- 

 vated that weaker branches and yellow leaves are the conse- 

 quence. Here are all the symptoms of the Yellows in the 

 peach, and thus we feel safe in believing that like effects 

 sprung from like causes. But we have since learned to 

 attribute precisely the same appearance in white pines, hem- 

 locks, maples, and some other trees, entirely to the attacks of 

 root fungus ; and why might it not be the same witli the peach- 

 tree Yellows ? On this suggestion, we have examined the only 

 peach tree with the Yellows that we have had a chance to see 

 during the past year ; and though not entirely satisfied with 

 this one examination, have little doubt that fungus at the root 

 will be found the cause of it. And if so, this will render clear 

 some practices that have been said to result in benefit, and yet 

 seemed enigmas to all of us who acted on other theories. For 

 instance, some have opened shallow trenches about peach trees 

 and poured boiling water in about the roots, and the Yellows 

 have disappeared. We have seen this, and know it to be true. 

 We have seen trees which were yellow for years, become green 

 in this way. Supposing the injury to result from a fungus 

 which fastens itself to the roots, and then works its morpho- 

 logical form through the bark into the structure of the tree, 

 hot water or a heavy dose of potash, applied as Dr. Wood ap- 

 plied it, would destroy the parasite, and thus produce the good 

 result we refer to. Now, we do not feel quite positive about 

 all this. But we see the effects of fungus in the yellow color 

 and behavior .of the tree, we have seen an isolated case in 

 which there was fungus at the roots, and we see in experi- 

 ments which have resulted successfully how well suited they 

 are to remedy a disease which might spring from such a cause." 



