New York Agricultural Experiment Station. 537 



artificially inoculate various varieties of cultivated apples with Gyra- 

 nosporangiuin Tnacropus have failed. In the spring of 1886, 

 Dr. Halsted ^ inoculated G. macrojnis on two varieties of cultivated 

 apple (Rawles Janet and Talnian Sweet), wild crab {Pirns coron- 

 aria ^\ pear, mountain ash, Pirus semipitmata, several species of 

 hawthorn and two forms of Juneberry on the grounds of the Iowa 

 Agricultural College, Ames, Iowa. In no case did Roestelia appear 

 on the cultivated apples. He says :^ " The individual experiments 

 numbered among the hundreds, and in every case there was a per- 

 fect failure of the Gymnosporangium spores to grow except with 

 the crab apple, where the inoculation was most emphatic." Further 

 inoculations were made the following season, 1887. He says : ^ 

 " During the present season cultural experiments with the native 

 cedar have been carried out by special students. It is an easy 

 matter to inoculate the wild crab with this, but only failures have 

 attended tests upon other plants." 



In 1893 Prof. L. H. Pammel ^ made some inoculation experi- 

 ments at Ames. A tree of the variety Tetofsky had been top- 

 worked with Fluke crab, which is an improved variety of Pirus 

 coronaria. G. macropus was inoculated upon both parts of the 

 tree, on the same day, with the same cedar apple. In due course of 

 time, Roestelia appeared in abundance upon the lluke crab portion 

 of the tree, but not a single leaf of the Tetofsky portion was affected. 

 Inoculations were also made upon pear, Japan quince {Cydonia 

 Japonica), cultivated apple and shadbush {Amelanchier almifolia), 

 but these all proved failures . 



The above is, in brief, the history of the experiments at Ames 

 previous to 1894. It appears to be well established that at Ames, 

 Iowa, the cultivated apple is wholly exempt from the Eoestelia 

 disease, which is very abundant and destructive in iSew England 

 and in some of the Southern States. The red cedar does not grow 

 spontaneously in Central Iowa, but it is frequently planted. There 

 are several specimens in different parts of the Agricultural College 

 grounds, some of them standing in close proximity to apple trees. 



2 Bulletin of the Iowa Agricultural College, from the Botanical Department. November, 

 1886, pp. 59-6J. 



3 Bailey considers the wild Pirns of Iowa to be specifically distinct from P. coronaria. He 

 has named it Pirns loensis. See L. H. Bailey : Notes from a Garden Herbarium VI; The 

 Soulard Crab acd its Rise. The American Garden, Vol. XII, p. 409. 



4 I. c. p. 03. 



5 Bulletin from the Botanical Dept. of the Iowa Agricultural College, February, 1888, p. 91. 



6 Diseases of Foliage and Fruit. Report of Iowa State Hort. Soc, Vol. X.WIII, 1S93, p. 470. 



