Hot-Water Treatment of Sugar Cane for Insect Pests. 



mained between 55° and 58°. being at 57° C. during the greater por- 

 tion of the period. 



These three lots were treated on March 14 and. with an untreated 

 check lot, were immediately taken to the field and planted in sandy 

 loam of favorable tilth and moisture content. The cuttings from 

 the treated lots were dug up on March 21 and examined: then re- 

 planted. These and also cuttings from the check lot were finally 

 dug up and examined on March 27. On March 23 two additional 

 check lots of cuttings from which all but the sprouted eyes had 

 been cut out were planted, and these were likewise examined on 

 March 27. The results obtained are shown in Table 1. Practically 

 all the sprouted eyes in each of the treated lots were included among 

 those recorded as " dead." 



Table 1. — Germination of sugar-cane eyes after treatment in hot water for 30 

 minutes at various temperatures. 



Items of comparison. 



Eve counts on 

 "March 21. 



Eye counts on 

 March 27. 



Good 

 eyes. 



Dead 

 eyes. 



Good 

 eyes. 



Dead 

 eyes. 



First lot: 30 eves, of which 4 were sprouted. Treated and planted 

 March 14 



25 

 27 



20 



3 



10 



24 



6 



Second lot: 30 eves, of which 3 were sprouted. Treated and planted 

 March 14 *. 



19 11 



Third lot: 30 eves, of which 8 were sprouted. Treated and planted 

 March 14 



5 25 



Check lot No. 1: Not treated. (Number of sprouted eyes not recorded.) 

 Planted March 14 





28 2 





30 



Check lot No. 3: Sprouted eyes onlv. Planted March 23 ■ 



29 1 



From these preliminary trials it became apparent that with seed 

 cane from which many eyes had sprouted and grown to a length of 

 half an inch or more there would be serious loss in the sprouted 

 eyes if the cane were subjected to the hot-water treatment. When, 

 about a week later, the ground was ready to plant in other experi- 

 ments, the cane had sprouted more extensively than was the case with 

 the cuttings used in the preliminary tests. It was therefore decided 

 to omit the hot-water treatment in the regular series of plats, and only 

 small plats from 0.04 to 0.06 acre each were planted with seed cane 

 subjected to the hot-water treatment. In this case from 50 to 100 

 pounds of cane were treated at a time in a tank of a size sufficient 

 to hold about four times the volume of water necessary to cover the 

 cane. The water was heated by the use of steam pipes in the bottom 

 of the tank, and accompanied with liberal agitation the temperature 

 was held during each treatment within one-half degree of 50° C. 

 Treatment in each case was for 30 minutes. In one instance the 

 germination of the treated cane was only about one-fifth as high as 

 that of the untreated cane in a check plat. In another test there 

 was practically no difference in the percentage of germination. In 

 both of these cases the germination was very low, owing to the dis- 

 eased condition of the cane as it came from winter storage in the 

 banks. From other lots of cane in the same field a pathological 

 examination of the seed cane revealed the presence among other 



