2 Department Circular SOS, U. S. Dept. of Agriculture. 



Prior to his experiments on destroying the moth borers by the hot- 

 water treatment, Doctor Brandes, in the course of his pathological 

 investigations (July and August, 1920), had made a series of tests 

 with sugar cane to determine the resistance of the eyes to the hot- 

 water treatment at different temperatures and for various durations 

 of time, and the possible stimulating action of such treatment. He 

 found that the eyes were not killed in the pieces of stalks bearing 

 single eyes used in his tests, with the temperature up to 50° C. and 

 for a duration up to 30 minutes (in some tests for a longer time and 

 in exceptional cases at higher temperatures) ; but that, on the other 

 hand, the treatment had an apparently stimulating effect upon the 

 rapidity with which the young shoots grew out from eyes of the 

 treated stalks. The results of these experiments also have not been 

 published, but the data were likewise reported to Mr. Holloway at 

 Audubon Park, in a letter dated August 17, 1922. 2 In the fall of 1922 

 field trials by W. G. Taggart, of the Louisiana Sugar-Experiment 

 Station, Audubon Park, New Orleans, confirmed these findings with 

 reference to the stimulating effect upon the growth of the young 

 shoots from the dormant eyes and thus also upon the percentage of 

 germination of the eyes. 



In the spring of 1923 the senior writer of these notes planned, 

 upon the strength of the above-mentioned published and unpublished 

 results, to apply the hot-water treatment to a series of plats in other 

 experiments on the sugar-cane experiment farm at Cairo, Ga. Not- 

 ing that the cane available for planting had sprouted extensively in 

 the banks, it occurred to him that eyes in the sprouted condition 

 might not possess the same resistance to the hot-water treatment as 

 did the dormant eyes in the cane used by Doctor Brandes in 1920 

 or by Mr. Taggart in the fall of 1922. He therefore suggested to the 

 junior writer of these notes, then temporarily stationed at Cairo, 

 Ga., that he make tests on a small scale prior to the time when it was 

 intended to plant the field plats. This was done and the following 

 data obtained. 



The cane was of the slender-stalk fibrous type, Cayana-10, in each 

 case here reported. Cuttings with two to four eyes were used. From 

 one-tenth to one- fourth of the eyes had sprouted and the shoots 

 grown to a length of half an inch or more. They were treated 30 

 minutes in each case in a copper tank 3 feet long, 9 inches wide, and 

 8 inches deep half filled with water, which was heated with a kero- 

 sene burner. 



In the first lot the initial temperature of the water was 52° C. 

 The addition of the cane cuttings caused the temperature to drop 

 immediately to 49.5° C. In 7 minutes it had reached 50°, and during 

 the remainder of the 30 minutes it was held between 50° and 51° C. 



In the second lot the initial temperature of the water was 52.5° C. 

 It dropped to 50° upon the addition of the cane cuttings and was 

 held between 50° and 51° during the 30 minutes, except during two 

 or three minutes when it reached 51.5° C. 



The third lot was put into water at 58° C, the temperature drop- 

 ping immediately to 55.3°. For 30 minutes the temperature re- 



2 It is with the consent of Doctor Brandes that these data and results selected from 

 his experiments on the effect of tlie hot-water treatment upon the moth borers and upon 

 the cane eyes are included in this report. 



