484 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
A few quotations from Ball (1) with reference to the absence of curly 
leaf in late plantings in the fog belt in connection with past outbreaks 
of the beet leafhopper corroborate the same fact observed in 1921. In 
1906, “a planting made late in May did not blight while others did.” 
In 1906, “plantings made May 22 and 31, at Soledad and June 3, at 
Spreckles did not show much blight while all earlier ones in these localities 
did.” 
The question has repeatedly been asked, why is it that late planted 
beets made a better tonnage than early plantings in the fog belt. The 
answer to this question involves the proper interpretation of some of 
the facts concerning the life history of the beet leafhopper. In the fog 
belt of the Salinas Valley, Stahl’s (3) “experiments conducted at 
Spreckels, California, demonstrated that there were unquestionably 
two generations annually in that locality.” When the pale green spring 
brood adults invade the cultivated areas, most of the specimens were 
found to be females. There are no flights associated with mating in the 
beet fields as the pairing of the sexes occurs on the foothills where most 
of the males remain and die. In the beet fields the females at the egg- 
laying stage make short flights for the purpose of disseminating the 
eggs. It is these females of the first generation and the nymphs of the 
second brood which cause a high percentage of curly leaf in March and 
April plantings in the fog belt. 
Investigations conducted in the fog belt of San Luis Obispo, Santa 
Barbara, Ventura, Los Angeles and Orange counties, showed that the 
second brood was greatly reduced in numbers when compared with the 
first generation. During the serious 1919 outbreak of the beet leaf¬ 
hopper a letter dated September 10, was received stating that swarms of 
hoppers were flying from beets when disturbed by the beet puller and 
another report that the horses became covered with leafhoppers during 
the harvesting of the crop in the fog belt of San Luis Obispo and Santa 
Barbara counties. These reports were not exaggerated but the leaf¬ 
hopper proved to be Empoasca viridescens. A week was spent in 
estimating the percentages of curly leaf in all of the beet fields and from 
6 to 92 per cent of the beets showed curly leaf symptoms. The beet 
leafhopper was extremely scarce, however, in fact, in most of the fields 
within the fog belt it was impossible to find a single specimen. The 
percentage of curly leaf was entirely out of proportion to the number of 
E. tenella present on September 19 to 25. It was found in the fog belt 
of these two counties that the adults had succumbed to a fungus disease. 
An examination of the lower surface of the leaves of a single sugar beet 
