U. S. D. A., 13. K. Bui. GO, Tart IV. Issued .January 27, 1009. 



SOME INSECTS INRIRIOUS TO TRUCK CROPS. 



THE LEAFHOPPERS OF THE SUGAR BEET AND THEIR RELATION 

 TO THE "CURLY-LEAF" CONDITION. 



By E. D. Ball, Ph. D.. 



Special Field Agent. 



INTRODUCTION. 



Ever since the introduction of the sugar beet into the intermountain 

 region more or less loss has resulted each season from a condition 

 called "curly-leaf," or "blight" (See PI. I, fig. 1, y; Pis. II, III; 

 PI. IV, fig. 1.) Around Grand Junction, Colo., the beet growers 

 have suffered frequent losses from this source. Supt. George Austin, 

 of the Utah Sugar Company, reported a serious loss around Lehi, 

 Utah, in 1897. In 1003 the beet crop in Sevier County, Utah, was 

 somewhat injured, the next year the damage was worse and more 

 widespread, while in 1905 it extended throughout the State of Utah 

 and the adjoining portions of Colorado and Idaho. 



Until 1905 the condition had been looked upon as a result of some 

 fungous or bacterial disease, or due to a soil or climatic condition. 

 During that season it was noticed for the first time that a leafhopper 

 {Evtettix tenella Baker) was present in large numbers in the fields 

 where this damage was the worst, and the writer, in connection with 

 his duties as entomologist of the Utah Agricultural Experiment Sta- 

 tion, commenced an investigation of the insect and its relation to the 

 damage. It was then too late to work out its life histor}^, so most 

 attention was paid to a study of its relation to the " curly-leaf " condi- 

 tion and to experiments with remedies. This investigation was con- 

 tinued in 190G and 1907, in cooperation with the Bureau of Entomol- 

 og)'-, and the life history was worked out. Owing to the small num- 

 ber of insects appearing these two seasons, little more was done with 

 remedies, but many new facts were learned in regard to methods of 

 attack and the causes of the injury. 



The writer's attention was first called to the " curly-leaf " in 

 August, 1900, by Prof. F. H. Shaw, then chemist of the Grand Junc- 

 tion (Colo.) Sugar Factory. A careful examination was made at 

 this time and again in succeeding years, but no explanation was found 



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