Nov. II, 1918 Sweet-Potato Storage-Rots 359 



FUSARIUM CULMORUM 



The experiments with Fusarimn culmorum Wollenw. as well as F. 

 acuminaium, to be discussed later, were for the most part carried out 

 like those of Gibberella saubinetii. 



Experiment I. — Eighty potatoes were thoroughly washed and divided 

 into two lots. One lot was disinfected in formalin (1:200) for 30 min- 

 utes. After inoculation by inserting spores and hyphae the treated lot 

 was wrapped in oiled paper and stored at 2.0° C. When they were 

 removed from storage, cultures were made from each potato. F. ctU- 

 morum was isolated in pure culture from 95 per cent of the treated and 

 25 per cent of the imtreated lot. The other potatoes were decayed, 

 but a miscellaneous lot of fungi, of which Mucor racemosus and Miicor 

 sp. predominated, was isolated. F. culmorum, was not isolated from 

 any of the controls. A more detailed discussion of the method may be 

 found under experiment I of Gibberella saubinetii. 



Experiment II. — The method of manipulation in this experiment 

 is identical with that of Experiment II of Gibberella saubinetii. Two lots 

 of potatoes (20 in each lot) were removed from the sweet-potato storage 

 house on March 11 and cultures made from each decayed or partially 

 decayed potato. Sixty per cent of the treated lot (formalin, i : 200, 

 30 minutes) were one-half to two-thirds decayed, and 80 per cent of the 

 untreated were partially to completely so, and F. culmorum was isolated 

 from all in pure culture. The other inoculated potatoes and the controls 

 remained sound. 



Experiment III. — For method see Experiment III of Gibberella 

 saubinetii. This experiment differs from Experiment III above in 

 that there were two lots, only one of which was treated. All these 

 potatoes were decayed when removed from storage, and F. culmortim 

 was isolated from 100 per cent of the treated potatoes and 95 per cent 

 of those not treated. While most of the controls were decayed, F. cul- 

 morum was not isolated from any. 



Experiment IV. — For method see Experiment IV of Gibberella 

 saubinetii. These sweet potatoes were kept in storage from September 

 9 to January 18, when they were removed and cultures made from those 

 partially or completely decayed. Ninety-five per cent of the treated 

 and 80 per cent of the untreated potatoes were rotted with F. culmorum 

 and the causal organism recovered in pure culture from each. 



Experiment V.— Chambers 4 (10.6° C), 5 (13.5° C), 7 (16.9° C), 9 

 (20.5° C), 10 (21.2° C.) of the Altmann thermostat and laboratory room 

 (23° C.) were used for this experiment. The potatoes were thoroughly 

 washed, then disinfected in mercuric chlorid (i : 1,000) for 10 minutes. 

 They were inoculated on November 6 by inserting spores and hyphae into 

 a wound at the end, after which they were wrapped in moistened filter 

 paper and then in oiled paper. On January 3 they were removed from 



