1908] EDGERTON—ANTHRACNOSES 397 



INOCULATION EXPERIMENTS 



As is well known, the forms occurring on fruits have been fre- 

 quently cross-inoculated by different investigators. Halsted (20-23), 



Cobb (iij, and many others have shown that the forms are easily 

 transferred. Halsted used fifteen or more fruits and vegetables, 

 and with a few exceptions he was able to transfer the forms at will. 

 This has been repeated by others; and during the past two years 

 I have made many similar transfers. Also the forms on raspberry 

 stems have been grown just as readily on apples as the original cul- 

 ture from apple {fig. 10). The forms which Halsted worked with 

 must have been mostly northern forms. 



Halsted (20) also believed that the forms on watermelon and bean 

 were the same, having inoculated both forms on a citron and obtained 

 identical spots. Other workers, as Sheldon (35), have failed to 

 get infection by inoculating spores from the melon fungus on the 

 bean; however, the young bean plant is not readily infected from 

 spores from the bean itself. 



Little has been done in transferring the forms that are known 

 to produce the perfect stage. Several investigators have transferred 



from 



and 



from these experiments it is generally recognized at present that 

 these two forms are the same. Recently Sheldon has also trans- 

 ferred the form from apple to the sweet pea and obtained successful 

 infection; this I have also confirmed. Leaves of young plants in 

 the greenhouse were inoculated from a pure culture from apple; 

 inoculation took readily and dead spots were formed. In one in- 

 stance the disease followed the petiole back to the stem, and after it 

 had entered the latter the whole plant vdlted and died. It is interest- 

 ing to note that the inoculations of the form found on apples in the 

 north to the sweet pea did not take so readily; only after the plants 

 began to die for want of water did they become infected. 



Another experiment was tried with leaves of rubber plant placed 

 in a moist chamber. The forms from Dracaena, Ficus elasHca, 

 Coffea, and Sarricenia were then inoculated on the leaves. In all 

 cases the fungi took readily, soon producing conidia in abundance; 

 later the forms from Dracaena and Ficus produced perithecia on the 

 leaf. 



