U. S. D. A., B. E. Bui. 109, Part VI. T. C. & S. P. I. I., September 16, 1912. 



PAPERS ON INSECTS AFFECTING YEGETABLES. 



A REPORT OF PROGRESS REGARDING THE SUGAR-BEET 



WEBWORM. 



(Loceostege sticticalis L.) 



By H. O. Maksh, 

 Entomological Assistant. 



INTRODUCTION. 



During portions of the years 1909 and 1910 and nearly all of 1911 

 the writer, stationed in the Arkansas Valley of Colorado and Kansas, 

 was engaged in a study of the insects affecting sugar beets and truck 

 crops. Among the foremost of the species of insects studied was 

 the sugar-beet webworm (Loxostege sticticalis L.). Although the 

 investigation of this pest has not been completed, control measures 

 have been fairly definitely worked out, and this preliminary article 

 is presented with the hope that it will stimulate greater interest in 

 the subject among the beet growers, and thus render the completion 

 of the study more easily accomplished. 



Sugar beets have been produced on a commercial scale in the 

 Arkansas Valley since 1900, and almost from the beginning this crop 

 has been infested by web worms. The injury produced by these in- 

 festations has varied greatly from year to year. During some seasons 

 little noticeable damage has occurred, while on a few occasions the 

 infested acreage has been extensive and the losses serious. As an 

 example it may be mentioned that in 1910 practically 4,000 acres of 

 beets grown for one of the sugar factories in the Arkansas Valley 

 were attacked. The serious nature of this outbreak was not realized 

 until too late, and although strenuous efforts were finally made to 

 control the " worms," the loss resulting from this infestation was esti- 

 mated at 20,000 tons of beets, which would have been worth approxi- 

 mately $100,000 to the growers. Such severe losses are rather excep- 

 tional, although nearly every year the loss occasioned by webworms 

 is far in excess of the amount imagined by the average beet grower. 



To the progressive farmers in the Arkansas Valley the sugar-beet 

 webworm is generally too well known to require a detailed descrip- 

 tion, although a few notes regarding the life history when infesting 



sugar beets may be of value. 



57 



