December, '17] 



MARSH: SUGAR-BEET WEBWORM 



543 



NOTE ON THE LIFE CYCLE OF THE SUGAR-BEET 

 WEBWORM' 



By H. O. Maksh, Scientific Assistant, Truck Crop Insect Investigations, Bureau of 

 Entomology, United States Department of Agriculture 



In 1912 the writer published a preliminary report^ on the sugar-beet 

 webworm (Loxostege stidicalis).^ 



At the time that bulletin was prepared the details of the life history 

 and egg-la>ing habits had not been definitely worked out. During the 

 years 1915 and 1916 a series of more detailed records were obtained 

 and the results are given herewith. The work was carried out in an 

 open-air insectary at Rocky Ford, Col. The insects were confined in 

 glass battery jars and the larvae were fed with the foliage of sugar 

 beets and lambs quarters (Chenopodium album). 



Table I. — Records of the Generations of Loxostege sticticalis at Rockt Ford, Col., During 1915 



Item 



First Generation 



Second Generation 



Third Generation 



Adults developed .... 

 First eggs deposited . . 

 First eggs hatched. . . 

 First larva; matured. . 

 First larvffi pupated . . 

 First adults developed 



Egg stage, days 



Larva stage, days. . . . 

 Pupa stage, days 



Total duration 



June 9, 1915 



June 19, 1915 



June 22, 1915 



July 8, 1915 



July 12, 1915 



July 25, 1915 



July 25, 1915 



July 31, 1915 



Aug. 4, 1915 



Aug. 19, 1915 



Aug. 24, 1915 



Sept. 9, 1915 



Sept. 9, 1915 



Sept. 16, 1915 



Sept. 20, 1915 



Oct. 27, 1915 



May 10, 1916 



June 2, 1916 



36 



40 



4 

 233 



23 



260 



1 Published by permission of the Secretary of Agriculture. 



2 The sugar-beet webworm, Bui. 109, pt. VI, pp. 57-70. 

 ' Family PyraUdae, order Lepidoptera. 



