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BOTANICAL GAZETTE. [ May, 



tempts to determine its cause and obtain suitable remedies or even to ac- 

 curately diagnose, as that of peach yellows. The unusual difficulties 

 which the study of this disease presents, lend much interest to all well 

 directed efforts toward elucidating the subject. The most important pa- 

 per in this line yet published is that of Mr. Erwin F. Smith, 1 recently 

 issued as Bulletin No. 9 of the Section of Vegetable Pathology of the De- 

 partment of Agriculture. The practical fruit-grower will doubtless feel 

 disappointed when he looks through this rather thick report, as he will be 

 unable to find answers to the two great questions: "What is the cause?" 

 and " What is the remedy?" But if Mr. Smith has not found the key that 

 unlocks the entrance to the field, he has certainly defined the limits of the 

 field, given a large amount of information regarding the lay of the land, 

 and carefully traced its history, in short has made a comprehensive and 

 lucid statement of the whole subject as it stands at the present timer 

 backed up by a long array of authority. 



The report covers the work of sixteen months, far too short a time to 

 institute and conclude much experimental evidence. The results of this 

 part of the inquiry will doubtless appear in a later report. But besides 

 properly assorting the incongruous views of others, Mr. Smith has added 

 valuable knowledge from his own observations, particularly regarding 

 the diagnosis of the disease and its distribution. 



There is record of peach yellows occurring near Philadelphia as 

 early as 1791, and it is known that peaches had been in cultivation in 

 this country for more than one hundred and fifty years prior to that 

 time. At first the disease was local, but rapidly became general in the 

 northern Atlantic states and spread westward and northwestward. At 

 present it is scarcely known in the Gulf states or west of the Mississippi, 

 and not at all on the Pacific coast. The author gives an idea of the large 

 amount of capital invested in the peach industry, and the heavy losses 

 which have resulted in many districts from the yellows. The disease 

 is found to be contagious, at least it can be communicated to healthy 

 trees by budding from diseased trees. The author speaks very cautiously 

 respecting the cause, suggesting micro-organisms as highly probable, 

 although he considers that root-aphides and root-fungi have some claims. 

 Much attention is given to the theory of soil exhaustion, so ably advoca- 

 ted by Dr. Goessmann and Prof. Penhallow, but the author finds it faulty 



and inconlusive. 



The illustrations of the report are well selected and well executed, 



especially the colored ones. 



Altogether, both the author and the public are to be congratulated 

 upon the excellence and completeness of this presentation of an economi- 

 cally important and difficult subject. The questions of cause and remedy 

 are yet to be answered, but with the evidence of good work before us, 



» SMITH, Erwin F.— Peach Yellows : a preliminary report. 8vo., 212 pp, 9 colored maps. 

 8^ partly colored plates. Washington 183& 



