146 Mortier F. Barrus 



pheasants, and other animals, passing through the field when the plants 

 are wet, may serve to carry the spores from one plant to another. 

 Insects, although minor agents, no doubt aid in inoculating healthy 

 plants. 



Gardner (1918:34) has shown conclusively that after a rain the spores 

 of Colletotrichum lagenarium are present in the soil beneath affected 

 plants, and that they may be disseminated by the spattering of such 

 soil during a rainstorm. He has shown also that spores may be carried 

 across a field in surface water during storms and washed or spattered onto 

 healthy plants, infecting them and thus greatly enlarging the foci of 

 infection. 



No field observations of the spread of the bean-anthracnose disease 

 were made during the three years when the writer's field work was done, 

 since the disease appeared to only a slight extent during that time. What 

 has been said regarding the spattering of contaminated water and soil 

 in the dissemination of the two diseases mentioned would seem to be 

 true in the case of C. lindemuthianum. Certainly the similarity of this 

 organism and C. lagenarium in the matters of spore production, character 

 of spores, and method of infection, would lead to the conclusion that the 

 means of dissemination and inoculation shown in the case of the cucumber- 

 anthracnose organism would exist also in the case of the bean-anthracnose 

 fungus. 



Infection of seeds 



The appearance and extent of the canker on the seed, and its progress 

 from pod to seed, are described on pages 107 and 111. As the pod matures, 

 the seeds within prepare for a resting period. The cells, now packed 

 with reserve food, become denser, drier, and more capable of resisting 

 decay. The mycelium of the fungus within the cells of the seed also 

 becomes less active, and possibly entirely dormant. It renews its growth, 

 however, at conditions of temperature and humidity to which the embryo 

 of the seed responds but slowly. There is probably very little activity of 

 the fungus in seed stored in a dry place. Halsted (1892:285) and others 

 report having found viable spores on and within spotted seed stored in 

 such a place, and the writer has often so found them. The acervuli were 

 black and dry, and it was not ascertained whether spores were being 

 produced under such conditions or whether they were produced earlier 



