322 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



be dissected to determine whether the remaining 50 per cent were not 

 weakened forms that had parasitic larvae within their bodies. Insects 

 at the end of their natural life often become sluggish and inactive and 

 of all of the leafhoppers taken only one dark form of the winter brood 

 was found. 



VI. Plants from Which the Beet Leafhoppeb Transmitted 

 Curly Leaf to Sugar Beets 



Boncquet and Hartung (2) have shown that 100 leafhoppers col- 

 lected on species of Artemisia and Atriplex in the Tulare Lake region 

 of California and confined singly in cages on beet seedlings failed to 

 produce curly leaf until they had fed on diseased beets. Smith and 

 Boncquet (4) tested fully 2,000 insects taken on Atriplex tularen&is 

 and Chenopodium album in the Tulare Lake region on several hundred 

 different sugar beet plants without the production of curly leaf in a 

 single instance. The writer has confirmed this result with hoppers 

 captured on different species of plants but adults and nymphs were 

 frequently caught which produced the beet disease. The beet leaf- 

 hoppers were taken in the natural breeding areas, cultivated districts 

 and deserts. Table II, gives a Ust of plants on which specimens of E. 

 tenella were collected and transmitted curly leaf to sugar beets. 



Table II — Plants on Which Beet Leafhoppers were Collected and Trans- 

 mitted Curly Leaf to Sugar Beets 



AT f 1 4. Locality beet leafhoppers „.]„Uo ^,. E. tenella 



Name of plant J^^^ collected ^^^l^I captured 



nympns 1918 



Atriplex elegans^ Niland 200 adults Apr. 21 



Niland 25 nymphs Apr. 21 



Calexico 300 adults Apr. 2 



AustraUan Saltbush 2 miles west Wasco 12 adults Dec. 14 



(Atriplex semibaccata)^ 



Lowland Purslane Dixieland 7 adults Mar. 13 



(Sesuvium sessile) 



Creosote Bush Victorville (desert) 2-4 miles 



(Larrea divaricata) from beet fields 14 adults Jan. 30 



Red Stem Filaree King City near beet field 3 adults May 27 



(Erodium cicutarium) . .King City, foothills 3 nymphs Nov. 28 



Bitterwater, base of foothills 100 adults Oct. 13 



Foothills, 13 miles southwest 12 adults Dec. 10 



Tracy : 18 nvmphs Dec. 24 



25 adults Dec. 24 



Nonvirulent adults reared from eggs and kept on Black Mustard 

 (Brassica nigra) failed to transmit curly leaf to sugar beets when 

 allowed to feed previously on Creosote Bush (Larrea divaricata) ob- 

 tained from the Mojave Desert and Imperial Valley. A nonvirulent 

 leafhopper caused curly leaf of a sugar beet when allowed to feed pre- 



1 Plants of the Saltbush Family (Chenopodiacese) to which the sugar beet belongs. 



