105 



ease is duo to a specific <iferin or microbe is uot settled. It may be of 

 a similar nature to pear blight and other kindred diseases, and perhaps 

 the same as that which often destroys the wild cherry, wild plum, and 

 sweet birch. There is no evidence that it is contagious. The symptoms 

 of this disease are briefly stated, and reference is made to previously 

 reported experiments in a small peach orchard on the college grounds 

 by I'rofessors (xoessmann and Penhallow and the author. The condi- 

 tions favorable to this disease are believed by the author to be im- 

 proper food supply, aiul injuries by cold, by the peach borer [JEgeria 

 c.fifiosa), and by any accident which reduces the vigor of the tree. 



(1) Food sKpph/. — " In almost every case investigated wliere tiie trees 

 are neglected and the food supply is small, the trees soon die, many of 

 them showing unmistakable signs of the yellows, while where the food 

 supj)ly is abundant and of a kind suited to perfect development the 

 growth is vigorous and healthy, and the trees often live from fifteen to 

 twenty years. 



"Too large an amount of nitrogenous manure, especially if applied so 

 that the trees do not get the benefit of it early in the season, results in 

 a late, immature growth of wood, that is often seriously injured by cold 

 during the winters, and this is followed the next season by signs of the 

 yellows. 



"The fertilizers recommended are equal quantities of muriate of pot- 

 ash and nitrate of soda, with about four times the weight of tine ground 

 bone, applied in March or April, from 5 to 10 pounds to the tree, ac- 

 cording to size. Wood ashes 5 pounds, ground bone 2 pounds, with 

 from one half to one pound of nitrate of soda to each medium sized 

 tree, will also prove very satisfactory. If the land is poor, containing 

 little organic matter, a liberal dressing of stable manure may be applied 

 in the fall ; but if the land is uot very poor, chemical manures will give 

 better results. All manures or chemical fertilizers should be applied so 

 that the trees may get the benefit of them early in the season. If very 

 soluble, they should be put on in March or April, but stable manure or 

 ground bone should be put on in the fall." 



(li) Injury by cold, borers, and accident, — When a late growth of the 

 trees occurs from any cause, as from too much nitrogenous manure ap- 

 plied late in the season, or from a warm, lale fall, the action of frost 

 during the winter often breaks the tissues in such a manner that they 

 can not be repaired during the next season's growth, and dead places 

 are often found on the trunk and main branches. These conditions are 

 very common in trees from eight to ten years old in most orchards of 

 New England. Injuries of a very similar appearance more frequently 

 occur as results of a decay of the tissues about tlie holes made by the 

 peach borer. The question is suggested whether these and other in- 

 juries result in the yellows, and observations are cited which imply 

 that they do. 



8219— No. 3 2 



