178 IOWA ACADEMY OF SCIENCES. 



name of Podosphaera oxyacanthae in which Galloway* makes the 

 statement that powdery mildew, Podosphaera oxyacanthae, is 

 especially destructive to seedlings in the nursery, attacking 

 them soon after the leaves unfold and continuing throughout 

 the growing season, making it impossible to bud them with 

 any success. There is still another reference by Gallowayf to 

 this same fungus. 



There may be several fungi concerned in this work. Dr. 

 Magnus t, in 1898, reported the fungus Sphaerotheca mali from 

 Slid Tirol on apple in which he confirms the conclusions of Pro- 

 fessor Burrill. The same year he reported it from Tirol. § 



Galloway II was aware of the occurrence of another fungus on 

 the apple, as will be seen from the following, which appeared 

 as a foot note in his article on powdery mildew: "We have 

 recently received from Mr. Swingle, of Kansas, an erysiphae 

 infesting apple seedlings, which does not appear to be this 

 species." Whether actual perithecia of Podosphcera oxyacan- 

 thce on apple have been commonly seen in this country is very 

 doubtful. It has been assumed to be Podospliaera oxyacanthce in 

 most cases. Like other mildews, climatic conditions do not 

 always favor the development of perithecia. As an illustration 

 we may cite Erysiphe graminis, which rarely produces peri- 

 thecia in Iowa. 



F. von ThtimenT^ records the Sphcerotheca castagnei Lev. F. 

 mali in Austria. He considers it only a well developed form of 

 the species. la this he agrees with the well-known German 

 phytopathologist, Sorauer. Sorauer^ stites that perithecia 

 have not been found on leaves, although the conidia are abun- 

 dant. Perithecia, however, occurring on the shoot. 



Fairchild- in his report on the successful treatment of this 

 disease, doubtfully refers this fungus to Podosphcera oxyacan- 

 thae. 



• Rep. U. S. Dept. of Agr. 1889: 414. 



+ Farmers' BuUetln, Office of Exp. Sta. 7:14. (Jour. Myc. 7:256.) 



$ Ber. d. Dutsch. Hot. Gesellsch, 16: 331. 1898. 



§ Die Enpipheen Tirols, Her. Naturw Med. Ver. Innsbruck 24: Separate, 5. 1898. 



II Rep. D. S. Dept. of Agrl. 1889: 414. 



^ Ueber elnlge besonders beachtenswerthedurch parasltlche Pllze hervorgerufen 

 Krankhelten der Apfelbaumblatter. Lab. Ohem-phys. Versuchss Stat. f. Wein u. 

 Obsbau. Klostemeuburg 14: Abst. Zeitsch f. Pflanzenk 1: 167. 



1 Phytopathologische Notlzen. Der Mehlthau der Apfelbaume Hedwlgla 18: 8. 

 He also has a foot note under the Galloway article, Zeitsch f . Pflanzenk 1 : 97 In which 

 he states what has been found In Germany. 



2 Jour. Myc. 7:256. 



