August, '19] SEVERIN: BEET LEAFHOPPER 323 



viously on the Lowland Purslane collected at Niland but two nonviru- 

 lent specimens failed to produce the beet disease from the Lowland 

 Purslane taken at Dixieland. 



Bur Clover (Medicago hispida) showed curly leaf symptoms caused 

 by about 300 beet leafhoppers collected on Filaree, Bur Clover and 

 Grass at the base of a foothill at Bitterwater on October 13. The 

 three leaflets were folded along the sinuous distortions of the mid-rib 

 and the transparent venation was evident on the youngest leaves. 

 The hoppers were confined in a cage enclosing Bur Clover and the 

 insects did not feed pre\dously on curly leaf beets in the laboratory. 

 After the curly leaf symptoms appeared on Bur Clover, some of the 

 bugs were transferred to a sugar beet which also later became blighted. 



The leafhoppers which hatched from eggs deposited in certain plants 

 collected in the cultivated area of the Imperial, San Joaquin, Sacra- 

 mento and Salinas Valleys sometimes caused curly leaf of sugar beets. 

 The weeds usually became dry in the cages in a week or two and the 

 nymphs probably were forced to feed on the beets in the later stages 

 of their life history. Table III, gives a list of plants from which the 

 hoppers were bred and transmitted curly leaf to sugar beets. 



Table III — Plants from Which Beet Leafhopper was Bred and Transmitted 



Curly Leaf to Sugar Beets 



Date Date 



Name of plant Locality plants collected ^Sleeted wereVred 



1918 1918 



Atriplex rosea^ 3 miles south Manteca Sept. 16 Oct. 22 



Fog Weedi Manteca, beet field Sept. 5 Oct. 22 



(Atriplex expansa) 



Atriplex bracteosa^ 11 miles east Los Banos Julv 14 Aug. 16 



Coalinga July 16 Aug. 13 



Manteca, beet field Sept. 5 Oct. 22 



Russian Thistle^ Chowchilla July 14 Aug. 16 



(Salsola kali var. tenuifolia) .Oro Loma July 15 Aug. 15 



Manteca, beet field . Sept. 5 Oct. 22 



Rough Pisweed Manteca, beet field July 11 Aug. 15 



(Amaranthus retroflexus) . . .King Citv, beet field July 31 Oct. 2 



Hamilton City, beet field .... Aug. 22 Oct. 19 



Tumble Weed King City, beet field July 4 Aug. 5 



(Amaranthus graecizans) . . . .Le Grand, beet field July 13 Aug. 16 



Amaranthus deflexus Manteca, beet field Sept. 5 Oct. 22 



Lowland Purslane Niland Apr. 7 June 3 



(Sesuvium ses.silc) 



Charlock Hamilton City, beet field Aug. 22 Oct. 5 



(Brassiea arvensis) 



Black Nichtshade King City, beet field July 4 Aug. 5 



(Solanum nigrum var. douglasii) 



If nonvirulent beet leafhoppers are not able to produce curly leaf 

 directly or indirectly l)y the action of a secretion poured from their 

 mouth-parts into the beet plant, it may be possible that a cycle of 



* Plants of the Saltbush Family (Chonopodiacese) to which the sugar beet belongs. 



