50 



first-named species is met Avith in cowpeas much less frequently than 

 the last two. 



The species breeding in the coAvpeas which served as check samples 

 to the series kejjt in cold storage were the cowpea weevil and the four- 

 spotted bean weevil. The principal food of these two species is the 

 cowpea, and they are found in most countries Avhere cowpeas are 

 grown. The first eggs are usually deposited in the field, but the 

 greatest damage is generally done after the seed is stored. The 

 beetles continue to develop in the dried and stored seed for several 

 generations. Under favorable conditions, depending chiefly on the 

 temperature, six or seven broods may develop within a year, according 

 to Doctor Chittenden's observations. If not checked their ravages 

 continue until the cowpeas are unfit for any practical purpose, not ' 

 even serving for the sustenance of the weevils. Plate II, fig. 1, shows ; 

 cowpeas which have been destroyed in this way. | 



CONDITIONS AND RESULTS OF EXPERI]NLENTS. 



The experiments herein discussed were conducted with Clay cowpeas 

 grown in Georgia in 1902. A germination test made of the bulk lot 

 in February, 1903, showed a vitality of 83.5 per cent. 



March 7, 1903, duplicate sets of twelve lots each, put up in cloth 

 bags, were stored in " trade conditions," and in cold storage at Wash- 

 ington, D. C., Richmond, Va., Jacksonville, Fla., and Xew Orleans, , 

 La. At each of these places the " trade conditions " were represented | 

 by seed warehouses. The cold-storage samples were subjected to a 

 temperature of 32° to 31° F. The remainder of the original bulk 

 was kept in the seed laboratory at a temperature varying from 55° to 

 80° F. Samples from the entire series were tested from time to time 

 for germination. The results of the tests are given in Table I. 



Table I. — Percentage of germination of cowpeas stored at various places under 

 "trade conditions" and in cold storage on Marcli 7, 1903, and returned from 

 storage at various dates. ^ ' 



Percentages of germination. 



Date of re- 

 turn of seeds 



Original 



Washington, D. C. 



Richmond, Va. 



Jacksonville, Fla. 



New Orleans, La. 



from stor- ouik lot 



















oratory. b 



Trade 

 condi- 

 tions. 



Cold 

 storage. 



Trade 

 condi- 

 tions. 



Cold 

 storage. 



Trade 

 condi- 

 tions. 



Cold 

 storage. 



Trade 

 condi- 

 tions. 



Cold 

 storage. 



Mav 1,1903 81 



. 84.5 



92 



83.5 



90.5 



90.5 



91.5 



83 



82.5 



June 1,1903 



(<-') 



96 



93.5 



97.5 



92.5 



94.5 



92 



94 



90 



July 1,1903 



(^) 



93 



94.5 



74.5 



87 



(c) 



90.5 



dll 



90 



Aug. 1,1903 



(c) 



rf68.5 



92.5 



(«) 



'87 



C^) 



83.5 



d27 



88 



Sept. 1.1903 



(^) 



(c) 



84 



(^) 



83.5 



(<•) 



as. 5 



(^) 



85 



Nov. 1,1903 



C"^) 



C") 



96.5 



e-) 



94.5 



(^) 



97 



C^) 



93 



June 1,1901 



- (4 



(<^) 



87.5 



C^) 



70.5 



(<') 



85 



(<■) 



75 



Nov. 1.1904 ; (c) 



(0) 



92 



(^) 



84.5 



e-) 



50 



(0 



" 



" The dates given are approximate only, varying slightly from actual dates of return of 

 seeds from storage. Germination tests in all cases were made within a very few days 

 after return of seeds from storage. 



"The original hulk sample germinated 83.5 per cent in February, 1903. 



'^ Destroyed by weevils. 



<* Many destroyed by weevils. 



