December, ’23] severin: investigations of beet leafhopper 479 
Empoasca sp. 60 
A pallia spp. 71 
Undetermined aphids found on diseased beets have been transferred 
to healthy plants on many occasions but without producing the disease. 
If, as now appears, no species of insect other than Eutettix tenella can 
transmit curly-top, some explanation of the peculiar adaptation in this 
case should be sought by further investigation. 
The paper was then discussed by Mr. E. Carsner, H. H. P. Severin, 
C. F. Stahl and other members. 
Chairman R. E. Campbell then called for the next paper on the 
program. 
INVESTIGATIONS OF BEET LEAFHOPPER (EUTETTIX TEN¬ 
ELLA BAKER) IN SALINAS VALLEY OF CALIFORNIA 
By Henry H. P. Severin, Ph.D., California Agricultural Experiment Station. 
Abstract 
The multiplication of the beet leafhopper ( Eutettix tenella Baker) in the Salinas 
Valley occurs chiefly on sugar beets. The nymphs were bred from eggs deposited in 
seventeen weeds growing in the cultivated areas. There was no evidence to show 
that a migration occurs from the San Joaquin into the Salinas Valley through the 
Coalinga-King City mountain pass. During the autumn dispersal the overwintering 
adults fly to the foothills, following the Salinas River and its tributaries. 
Early planting of sugar beets (December to February) is the only known practical 
method of preventing losses from curly leaf in localities outside of the fog belt. In 
the fog belt districts late planted beets make a better tonnage than early plantings, 
in a normal season of rainfall. Planting should be discontinued from March 1„ 
until after the spring dispersal. The limit of beet growing in the fog belt as far as 
curly leaf is concerned varies from 20 to 30 miles in California. 
I. Location and Boundaries 
The Salinas Valley is the largest of the many valleys inclosed within 
the Coast Range in California. From Monterey Bay it extends in a 
southeasterly direction, in a line parallel with the coast, to its head—a 
distance of about 100 miles. Its average width is from 7 to 9 miles. 
Upon the northwest the valley is bounded by Monterey Bay; upon its 
sides by the Sierra Santa Lucia and Sierra Salinas ranges, with their out¬ 
lying spurs upon the west; and by the Gabilan and Mount Diablo 
ranges upon the east, the latter separating the Salinas Valley from the 
San Joaquin Valley of the interior of the State. 
II. Introduction 
«■ 
Ball (1) believes that the beet leafhopper migrates from the San 
Joaquin into the Salinas Valley. He found the leafhoppers “breeding 
in abundance on the native Atriplex in the Tulare region. This district 
