188 Investigations in Plant Pathology 



of a " black peach aphis from Dr. W. S. Maxwell, Still Pond, Md., 

 taken from [the] nursery of John Stokes." In Entomologica 

 Americana-^ he published his description of "The Black Peach 

 Aphis. A new species of the genus Aphis." His first account, 

 appearing in his preliminary report on peach yellows, had been 

 prepared before he had seen the winged form. If Smith did not 

 investigate the insect as an agent of transmission, he did study it 

 as a possible cause of the disease. In the continuation-^ of hfs 

 article, he said: 



I first collected the winged viviparous form at Still Pond, Md., in 

 April, 1889. . . . This aphis has been called " The peach phylloxera," 

 and the injuries due to it are very considerable. The " Yellows " itself 

 has been ascribed to it, but on insufficient evidence. On the whole, it is 

 more to be dreaded than the borer or the curculio. 



Insecticides and spraying could rid the insects when above 

 ground. When, however, the insect was underground, unless 

 some preventive remedy applied to the roots before planting 

 could be devised, no certain method to destroy the insect was 

 known. 



During these years, furthermore. Smith was devoting much time 

 to studying Monilla fructigena, the causal fungus of peach rot 

 and blossom blight and canker of the shoots and stems. His field 

 notes were filled with observations and experimental data on 

 many peach diseases: among them, leaf curl, brown rot, black 

 spot, mildew, rust, yellows, and rosette. -'' West, north, south, and 

 east throughout the United States, these notes and data were 

 taken. The Monilta "^ research, however, was important in that in 

 considerable part, both as to time and place, Smith's work of 

 describing the diseases and life history of the causal fungus 

 paralleled his experimental researches in peach yellows. Besides 

 showing that the fungus overwintered in mummied fruit and that 

 orchard hygiene was of more value than the few fungicidal treat- 

 ments known, he demonstrated his ability to conduct, side by side, 



''*6 (6): 101-103, June 1890. 



*°The black peach Aphis (Aphis persicaeniger n.sp.), Ent. Amer. 6 (11): 201- 

 207, 1890, quotation at pp. 204-205. 



=» Field notes, 1890, Jour. Myc, op. cit., 6: 107-110; Field notes, 1891, Jour. 

 Myc. 7 (2): 88-94. 



"Peach rot and peach blight. Jour. Myc. 5 (3): 123-134; Peach blight. Jour. 

 Myc. 7 (1): 36-38, Sept. 10, 1891. The first, Sept. 1889; the second, Sept. 1891. 



