New York Agricultural Experiment Station. 539' 



Fluke crab and wild crab. Natural cultures of Roestelia on wild 

 crab were rare. 



In the spring of 1S95, one of us being on Long Island, N. Y., 

 and the other at Amee, Iowa, we again undertook some experiments 

 with G. macropus. We will speak iirst of the experiments on 

 Long Island. They were conducted in the nursery of Isaac Hicks 

 & Son, at Westbury, N. Y. On May 18, four varieties were inocu- 

 lated with New York G. macropus — Yellow Transparent, Red 

 Astrachan, Ben Davis and Red Pippin. The first three were two- 

 year-old nursery trees; the last was a large tree. Many leaves on 

 one tree of each variety were smeared, both sides, with the gela- 

 tinous spore-masses of G. macropus. The results were as follows : 

 Yellow Transparent showed no sign whatever of lioesteJia. Both 

 Red Astrachan and Ben Davis showed yellow spots which appeared 

 like the beginning of Roestelia, but none of them developed. Red 

 Pippin produced the Roestelia, but the spores did not mature prop- 

 erly and the fungus presented a stunted appearance. On May 24, 

 six varieties were inoculated with Iowa G. macropus — Yellow 

 Transparent, Red Astrachan, Ben Davis, Red Pippin, Maiden's 

 Blush and \yealthy. All were two-year-old nursery trees except 

 the Red Pippin. One tree of each was inoculated as before. The 

 results were as follows : Yellow Transparent and Red Pippin 

 showed no signs of Roestelia. Red Astrachan and Ben Davis 

 started Roestelia spots which never matured. Maiden's Blush and 

 Wealthy developed numerous Roestelia spots and matured the 

 aecidiospores thoroughly. As no bags were used to cover the inocu- 

 lated leaves, it can not be said positively that the Roestelia on 

 Maiden's Blush and Wealthy resulted from the Iowa G. macropus, 

 but the conditions were such as to warrant the above conclusions. 

 In the case of Red Pippin, there can be no doubt as to which 

 inoculation produced the Roestelia. A large tree which stood at a 

 considerable distance from the other inoculated trees, was inocu- 

 lated on one side with New York G. macropus and on the other 

 side with Iowa G. macropus. The leaves of the branch inoculated 

 with New^ York G. macropus, and a few other leaves in the imme- 

 diate neighborhood, produced Roestelia, while the remainder of the 

 tree showed not a Roestelia spot. It is also practically certain that 

 all of the Roestelia found in connection with these experiments 

 was the Roestelia of G. macropus. Careful search was made in 



