THE DISEASES OF THE PEACH TREE. 37 



added to their o-wii observations and placed before you in this report, will serve 

 to direct yonr attention to a careful study of the peach tree, and diseases to 

 which it seems peculiarly liable. 



As above stated, your committee found the Yellows had attacked peach trees 

 in some of the orchards at St. Joseph, Benton Harbor and South Haven, but 

 at no point north of South Haven. 



Their observations lead them to the conclusion that the primary cause of 

 the Yellows is a weakening of the trees by overtaxing the soil, thus depriving 

 them of a large portion of the sustenance they should receive from the earth ; 

 then allowing them to ripen large crops of fruit for several years in succession, 

 thus reducing their strength and ability to resist disease. 



With regard to the Fungus theory yonr committee do not think it the 

 ■original cause of the disease, but where it occurs it is the result of the weaken- 

 ing process that has been going on, placing the trees in a condition for a 

 fungus, as it alights upon them, to strike root and grow. As a general thing 

 fungi do not fasten to and grow upon perfectly healthy objects, but upon 

 debilitated, enfeebled, diseased, or dead objects. Mr. M. C. Cook, of England, 

 probably the highest authority upon the subject of fungi, in his book entitled 

 "An Introduction to the Study of Microscopic Fungi," says: "It is possible 

 that the granular fluid contents of the spores may be absorbed by the plant, 

 and as a result of this absorption, become innoculated with the virus, which at 

 length breaks out in fungoid growths. Much has been done to elucidate this 

 mystery of innoculatiou, but much also remains a mystery still. There is no 

 doubt that the innoculation takes place at an early age, probably in the seeds 

 of many plants; in others it may be conveyed with the moisture to the roots; 

 but the spores themselves have certainly not yet been traced traversing the 

 tissues of growing plants." 



Your committee have no doubt but that the disease called the Yellows, 

 whatever it may be, may be reproduced by planting pits taken from the fruit 

 of diseased trees. The disease will, we think, sooner or later be developed in 

 trees thus produced, no matter on what soil they are grown, or how well they 

 are cared for. 



It has been noticed, and often stated, that in one season one tree only in an 

 orchard will show the Yellows; the next season another tree in the same 

 orchard, standing at quite a distance from the first one aflfected, will be de- 

 stroyed by the same disease, while trees standing near the first named show no 

 signs of disease. This is used as an argument against the theory that the 

 disease is contagious, but it may be an argument in favor of the doctrine that 

 the diseased trees were infected by being grown from diseased pits or diseased 

 buds, while the other trees were not so produced. 



Yonr committee would recommend to orchardists to destroy every peach 

 tree on their premises that shows signs of being infected with the Yellows, and 

 not to raise stocks from seeds of diseased trees, or to bud their stocks with buds 

 taken from diseased trees, or to purchase trees from a district where the disease 

 is known to prevail. 



All of which is respectfully submitted. 



J. C. HOLMES, 

 H. G. WELLS, 

 S. 0. KNAPP, 



Committee. 



