146 EXPERIMENT STATION RECORD. 



and it was found that placing them on ice for 15 minutes or 1 hour or in 

 ice water for 1 hours had no appreciable effect upon their germination. 



During the years 1894, 1805, and 1890 field experiments were con- 

 ducted to determine the relation of smut in the land to the amount of 

 smut in the crop, and it was ascertained that previous crops of diseased 

 broom corn bore no relation to the infection of a subsequent crop grown 

 upon the same soil, and that the hot- water treatment greatly lessened 

 the amount of smut panicles. 



The experiments seemed to indicate that the fungus gains entrance 

 into the host immediately after germination, and smut spores placed 

 upon the young plant as it emerged from the ground gave no increase 

 in the amount of smut. 



The relation of host and parasite is considered at some length and an 

 historical review of the bibliography and nomenclature of the fungus is 

 given. A summary of results and complete directions for the preven- 

 tion of broom-corn smut by the hot-water treatment completes the 

 bulletin. 



Notes on celery diseases, L. F. Kinney (Fltorfe Island Sta. Bui. 

 44, [>p. 19-25, figs. 3). — Notes are given on the occurrence of black heart, 

 blights, and blast of celery. These diseases are apparently not pecul- 

 iar to any particular variety, and there is no indication that the spores 

 are introduced with the seed when planted. The somewhat general 

 belief that excessive drought causes these diseases was not borne out 

 in the experiments, since black heart and blight prevailed in the 

 irrigated sections of the fields. The general belief appears well founded 

 that considerable clay in the subsoil is an important factor in celery 

 culture, which is probably due to its preventing the drying out of the 

 soil. Bordeaux mixture seemed to check the disease upon the leaves, 

 but later in the season, when the weather became cool and the mixture 

 washed from the leaves, little if any difference could be detected in the 

 appearance of the rows which had been treated and those which had 

 not. Tlie previous growth of celery on the land seemed to bear no 

 relation to the amount of black heart and blight on the plants experi- 

 mented with, and there were no indications that the diseases were 

 particularly contagious. 



There appears to be some relation between the celery diseases and hot 

 weather, since they always appeared m the most violent form either 

 during or subsequent to a period of high temperature. It is probable 

 that the celery plants can perform their functions in an atmosphere 

 with high temperature, provided the soil about their roots is moist and 

 cool. In investigating this point the effect of trenching and mulching 

 was considered to some extent, and it was found that while a lack of 

 proper protection of the roots was not the sole cause of celery disease, 

 yet this seemed to be the principal cause in the cases where level cul- 

 ture was practiced. 



The familiar occurrence of hollow-stalked plants is mentioned, ant 



