74 
IOWA ACADEMY OF SCIENCES. 
EFFECTS OF HEAT ON THE GERMINATION OF CORN 
AND SMUT. 
BY P. C. STEWART. 
Bunt and smut of oats are successfully combatted by treating 
the seed with hot water previous to planting. Since the dis- 
covery of this method by Jensen, a great many experiments 
have been made both in Europe and America. The success with 
bunt and oats smut naturally directed the attention of investi- 
gators to hot water treatment for corn smut, but experiments 
made by PammeU and others proved it to be ineffectual. 
Very few tests have been made to determine the thermal 
death-points of different smuts. Hoffman and Schindler have 
tested several economic species. It is evident that nothing can 
be accomplished by treatment with dry heat, for the corn smut 
spores are capable of withstanding a much higher temperature 
than the corn itself. Hence the investigations recorded in this 
paper may be of little practical importance, but considering 
that the literature on the subject is exceedingly meager, they 
may have some interest. Much work has been done in testing 
hot water and chemicals for other smuts, f 
*Iowa Agricultural Experiment Station Bulletin, No. XVI. 
+ J. Kuehn, Bot. Zeitung, 1873, p. .^03. 
Kellerman and Swingle, Kansas Agricultural Experiment Station, 1889. Second 
Annual Report, pp. 313-388. Also Bulletins Nos. 13 and 15. 
Kellerman, Kansas Agricultural Station Bulletin, Nos. 31, 33 and 33. 
Sorauer, Pflanzen Kraukheiten. pp. 303-308 
H. L Bolley, North Dakota Agricultural Experiment Station, Bulletin No. 1. 
J. O. Arthur, Indiana Agricultural Experiment Station, Bulletin Nos. 38, 33 and 35. 
Fletcher, Central Experimental Farm, Ottawa, Canada, Bulletin No. 3. 
J Fremont Hickman, Ohio Agricultural Experiment Station, Bulletin No. 6, VoL 
III, Series II, and Bulletin No. 1, Vol. V, Series II. 
Ustilago Maydis, Pammeh Experiments with Fungicides. Iowa Agricultural 
Experiment Station, Bulletin No. 16, p. 316. 
Tilletia caries. Dry heat 80° C. for two hours did not destroy all of the spores . 
Above 95° C. spores no longer germinated. Schindler. Euber den Einfluss verschiede- 
ner Temperaturen auf die Keimfahigkeit der Steinbrand Sporen. Fortschritte auf 
dem Gebiete der Agriculturphysik, Vol. III. Heft 3, 1880. Zoph, Die Pilze, p. 316. 
Ustilago carho and 17. destruens. Dry heat 104-138® C. 17. Carho is destroyed with 
moist heat between 58.5® and 63® C. U . destruens is destroyed when heated to 74-78® 0. 
for one hour; for two hours the maximum temperature is 70-73® C. Hoffman, Jahrb fur 
Wissenschaftl. Botanik II, 1860, p. 367. Zopf. 1. c., p 316. 
