48 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



were coming in in numbers this spray would need to he foUowed by a 

 second one 10 days later. 



Several mechanical devices have been used to catch different leaf- 

 hoppers, and no doubt several of these could be used against this insect 

 with advantage. The tar pan, or " hopper-dozer," drawn over the 

 beets two or three times in the first few weeks would capture a large 

 number of them. The females, before the eggs are laid, are quite 

 heavy and do not jump or fly as readily as the males and would be 

 easily caught. A modified form of this machine, consisting of a 

 €Ouple of tarred wings to be drawn along on each side of a row of 

 beets, while a drag agitated the tops and caused the insects to fly, 

 would probably capture more than the simpler tar-pan. 



If the insects appeared while the beets were quite small, they could 

 be largely destroyed by rolling Avhen the weather was cold or damp 

 and the insects sluggish. 



A number of preventive measures may be used to assist the beets 

 in withstanding the attack of the leafhoppers. In some sections early 

 planting will produce beets large enough to shade the ground by the 

 time the beet leafhoppers appear, and thus reduce the temperature 

 below the danger line. In a few places, like the Grand Junction dis- 

 trict in Colorado and Sevier County in Utah, early planting alone 

 would not avail, as the insects appear soon after the earliest beets 

 come through the ground. For such sections early and frequent irri- 

 gations would assist in keeping the ground cool until the beets grew 

 large enough to shade it and thus take care of themselves. 



All i)reventive measures will depend for success upon some method 

 of controlling the temperature in the field so that the ground may not 

 be hot and dry at the time the leafhoppers appear. 



BIBLIOGRAPHICAL REFERENCES. 



1895. Gillette, C. P., and C. F. Baker. — A preliminary list of the Hemiptera 



of Colorado.<P,ul. 31, Colo. Agrie. Exp. Sta., p. 100. 



On sugar beets in Colorado. Mention as Thamnotettix tenellus Uhl. MSS. 



1896. Baker, C. F.— New Hemiptera. <Psyche, Vol. VII, Suppl., p. 24. 



Species described from New Mexico as Thamnotettix tcnclhis n. sp. 

 1900. Forges, S. A., and C. A. Hart. — The economic entomology of tLe sugar 

 beet. <Bul. 60, 111. Agric. Exp. Sta., pp. 423, 523. 

 On sugar beets in Colorado. Mention as Eutettix tenclta Bale. 



1903. Chittenden, F. H.— Yearbook U. S. Dept. Agric. f. 1902, p. 730, 1903. 

 Mention. " Reported as injurious to sugar beet in Arizona." 



1900. Howard, L. O.— Yearbook U. S. Dept. Agric. f. 1905, p. 630, 1906. 

 Injury in Utah. Mention as Eutettix stricta Ball. 



1907. Ball, E. D.— Report of the entomologist. <16th Kept. Utah Agric. Exp. 



Sta., p. 16. 



Character of injury and damages in 1905. Mention as Eutettix tcnella Bak. 

 1907. Ball, E. D. — The genus Eutettix. <Pr<)c. Davenport Acad. Sci., Vol. VII, 



pp. 27-94, Pis. I-IV. 



.\ systematic and economic review of the group, with original illustrations. 

 60— IV 



