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Journal of Agricultural Research 



Vol. XIII, No. II 



tested — viz, P. cerasus, P. avium, P. mahaleb, P. pennsylvanica, P. 

 domestica, P. virginiana, and P. serotina. Details regarding the relative 

 consistency and abundance of the infection induced in these crosses are 

 found in Table IX. P. cerasus and P. amum were infected by inocula 

 from P. cerasus, P. avium, P. mahaleb, and P. pennsylvanica, though in 

 the case of P. cerasus the cross from P. pennsylvanica was effected but 

 once in lo trials. P. pennsylvanica showed a narrower range of sus- 

 ceptibility, being infected by inocula from P. pennsylvanica and P. 

 mahaleb only. It should be remembered, however, that this cross was 

 tried but twice with strains from P. cerasus and three times with inocula 

 from P. avium (see footnote d. Table X). P. serotina and P. virginiana, 

 respectively, were infected only by their own strains. P. padus was 

 infected only by strains from P. virginiana. The results with P. padus 

 are of special interest, inasmuch as this is the host upon which Karsten ^ 

 originally described Cylindrosporium padi. 



Table X. — Siimmary of results of crosses tried in inoculation experiments with Cocco- 

 myces spp.from. Prunus spp., Madison, Wis., igi6 and igiy 



o Compiled from Table IX. A single positive result serves to list the results of a cross as positive, even 

 though a large number of tests may have given negative results. See footnote c. 

 ^ Positive results were obtained only after prolonged incubation in the greenhouse. 

 '^ This cross was effected but once in 10 trials. 

 d The number of experiments was limited, owing to the failure of experimental plants to root. 



Of the plums tested, P. insitiiia showed the widest range of susceptibil- 

 ity, being infected readily by strains from P. domestica, fairly consistently 

 though rather sparsely by strains from P. virginiana, and difficultly by 

 inocula from P. cerasus, P. mahaleb, and P. serotina. P. domestica was 

 infected consistently and abundantly by its own strains, and more 

 difficultly by strains from P. virginiana. P. americana and P. salicina 

 were infected only by inocula from P. domestica, the former abundantly 



'Karsten, P. A. symbolae ad mycoiogiam fennicam. 

 Fennica, Haitet 11, p. 159. 1885. 



pars XVI. In Meddel. Soc. Fauna et Flora 



