July io, 1916 



Storage-Rots of Economic Avoids 



569 



Results with Sclerotium rolfsii. — This organism produced no decay 

 at the end of 38 days in chamber 5 (9.1 C), but a few immature sclerotia 

 were formed. In all the other chambers visible growth appeared in 

 two days. In chambers 6 (14.0 ) and 9 (18.4 ) hyphffi were abundantly 

 produced and the sterile blocks completely decayed, but no sclerotia 

 were produced at the conclusion of the experiments. At the three higher 

 temperatures the blocks were also decayed, but the production of hyphae 

 was markedly less and the number of sclerotia relatively larger, increasing 

 in number with the increase in temperature. It therefore appears that 

 the minimum temperature at which this organism will produce decay is 

 near 8° to io°. Other things being eliminated, dasheens would appar- 

 ently, from the results of these experiments, keep better if stored at a 

 temperature of about 8° to io°. 



Results with Bacillus carotovorus. — Experiments to determine 

 the range of temperature of B. carotovorus were made some months later 

 by inoculating sterile raw blocks of turnips and dasheens. The blocks 

 were inoculated with a 24-hour-old culture of strain 3616 grown in beef 

 bouillon and exposed in a series of chambers of the Altman thermostat 

 and in the laboratory room to the following average temperatures: 



The tubes were kept in the chambers for 27 days. At the end of that 

 time no growth had taken place in chamber 2 (4 C.) and but a 

 slight growth in 3 (6.1 ), and 20 (39.3 ). In six days a slight decay 

 had started in chamber 5 (io°) and in three days in chamber 6 (12.3 ). 

 At the end of 14 days the dasheens were completely decayed in chamber 

 5. The turnips, on the other hand, were only partially decayed at the 

 close of the experiment. In chamber 6 the dasheens were completely 

 decayed at the end of 1 1 days and the turnips nearly so at the end of 14 

 days. In all the other chambers decay was noticeable at the end of two 

 days, but progressed more rapidly with the increase of temperature up 

 to and including 18 (32. 7 ). At the end of 11 days the dasheens were 

 completely decayed in chamber 8 (16 ) and the turnips mostly so, 

 while in 9 (17.3 ) the dasheens were completely decayed in 7 days 

 and the turnips in 11 days. In chamber 18 (32. 7 ) both dasheens and 

 turnips were completely decayed in 3 days, while in 19 (35.8) decay 

 was not complete until 10 days. A parallel series, of tests was run 



