August, '19] SEVERIN: BEET LEAFHOPPER 317 



acreage in the San Joaquin Valley. A conservative estimate of the 

 number of leafhoppers in the beet fields in 1918, compared with the 

 enormous numbers found on the Fog Weed, A. rosea and A. hracteosa 

 in the San Joaquin Valley would be 1 : 1000. 



In the spring the beet leafhopper was found in enormous numbers on 

 short-lived annual Atriplex, such as A. cordulata and A. coronata. At 

 Volta, A. cordulata was growing in an alkali sink and when these plants 

 became dry, the nymphs and adults probably moved to the Fog Weed 

 also growing in the basin, and the same apparently was true in a sink 

 at Cholame, — when A. coronata became dry the nymphs and adults 

 probably congregated on the Fog Weed. In irrigated districts, the 

 insects were commonly taken on A . coronata and A . phyllostegia during 

 the middle of July, but when these plants bear seeds the hoppers 

 gradually disappear. It was frequently noticed that when the stems 

 of other species of plants became woody the bugs left, but this was not 

 the case with the Fog Weed, A. rosea and A. hracteosa, the leafhoppers 

 often remaining on these three species of plants until the leaves became 

 dry. 



The beet leafhopper was captured on 30 species of plants in the 

 cultivated area, 18 of which belong to the Saltbush family. The pest 

 was most abundant on different species of Atriplex. 



E. tenella was bred from a large number of plants growing in the 

 cultivated area of the San Joaquin Valley. The weeds were collected 

 in vacant fields, stubble fields, beet fields, truck crop fields, along 

 roadsides, railroad tracks, rivers, irrigation and drainage canals. 

 About a dozen weeds of each common species were gathered at random 

 and each species was placed in a large paper bag. In the hothouse 

 the roots of the plants were put into a tumbler or jar of water and 

 placed in a cage together with a potted sugar beet. The weeds and 

 beet were Avatered dail}' through a hole in the cheese cloth on the top 

 of the cage and then the hole was plugged with cotton. Caterpillars 

 and spiders were removed from the cages. It is evident that the eggs 

 were deposited in the vegetation under natural conditions, and bj' this 

 method the females were not forced to oviposit in the plants. The 

 insects were reared to the adult stage. Table I gives a list of plants in 

 which the beet leafhopper deposited its eggs in the cultivated districts 

 of the San Joaquin Valley. 



