18 II. E. Thomas and W. D. Mills 



by G. yamadae. Xo aecia of G. juniperi-virginianae have been found on 

 Mcintosh foliage from either artificial or natural infection. Inocula- 

 tions on Wealthy foliage produced the usual symptoms associated with 

 this fungus on a susceptible variety. 



With G. globosum, ten inoculation tests were made on Mcintosh 

 foliage in the greenhouse and eight parallel tests were made on Wealthy. 

 Six of the inoculations on Mcintosh produced recognizable infection 

 varying from a few spots to 46 spots on one leaf. On Wealthy, only 

 one inoculation produced certain infection which was evidenced by a few 

 minute orange spots (with pyemia ) and many small necrotic spots. One 

 other inoculation was followed by necrotic spots which resembled those 

 of the preceding test but were not accompanied by pyenia or by orange 

 color. Of three inoculations on Mcintosh foliage in the field, two 

 produced a small amount of infection but not equal to that produced 

 by G. jv/niperi-virginianoA in comparable tests. 



In summary of the inoculation trials of Mcintosh and Wealthy 

 foliage, it is of interest to note that G. germinate did not infect either 

 of these varieties, that G. jimiperi-virginicma-e infected both varieties 

 readily but the development of lesions in the Mcintosh leaf was 

 checked at an early stage, and that G. globosum infected both varieties 

 but the Wealthy only with considerable difficulty. 



During the latter part of the season of 1928, abundant rust material 

 on a considerable number of varieties was available in the Hudson 

 Valley. Thus a determination of the kind of rust involved was usually 

 possible by the direct examination of aecia and pyenia of the fungi. 

 Symptoms also were useful, within limits, as circumstantial evidence. 

 As a result of all the evidence, it is concluded that the three diseases 

 which are generally prevalent on the red cedar in the Hudson Valley 

 are very common also on varieties of cultivated apples. 



EPIPHYTOLOGY 



The relations of rains and atmospheric humidity to infection, in the 

 apple rust, are fairly well known. The relations in the hawthorn and 

 quince rusts seem to be essentially similar. In the season of 1928, 

 marked by a severe epiphytotic of all these diseases, the United States 

 Weather Bureau Station at Hudson, New York, recorded, for the 

 months of May and June, 1.69 and 7.89 inches of rain, respectively, 

 as contrasted with 4.18 and 3.79 inches mean precipitation for that 

 station. From May 18 to June 18 inclusive, 7.29 inches of rain was 

 recorded, anel from May 18 to June 6 there was never more than a 

 one-day interval between rains. In 1927, when rust was rather severe, 

 the rainfall was high in May (5.20 inches) and moderate in June 

 (3.06 inches). 



