December, ’23] severin: investigations of beet leafhopper 
483 
preventing serious losses from curly leaf in localities outside of the fog 
belt. The fact that the adults leave the cultivated areas in the autumn 
has an important bearing with reference to the time of planting beets. 
In a dry autumn it is necessary to pre-irrigate the soil. In the Salinas 
Valley the adobe soil becomes very sticky when wet, and it is practically 
impossible to work the soil after the rainy season begins. Beets should 
not be planted until the end of November outside of the fog belt between 
Soledad and King City. 
VIII. Fog Belt 
Ball (1) in discussing the time of appearance of swarms of beet leaf- 
hoppers states that flights have occurred in the Salinas Valley “at 
different seasons and apparently in some instances at different times in 
the same season.” During the past six years large numbers of spring 
brood adults invaded the fog belt of the Salinas Valley during 1919, 
1921 and 1922. The leafhoppers were distributed in all beet districts 
of the valley on the dates given under spring dispersal. The spring 
invasion of the first brood into the fog belt probably depends upon the 
absence of fog at dusk when the flights occur. During 1918, 1920 and 
1923, the fog belt was not entirely free from leafhoppers, although great¬ 
ly reduced in numbers. 
IX. Late Planting of Sugar Beets jn Fog Belt 
According to Schwing and Hartung (2), “in the fog belt districts more 
leafhoppers were present and a higher percentage of curly leaf occurred 
in early planted beet fields than in fields planted after the invasion of the 
pest had occurred in the Salinas Valley.” At Santa Rita, about eight 
miles from the Pacific Ocean, 60 per cent of the early planted beets were 
blighted compared with 3 per cent in an area replanted cn account of 
the disease in the same field. March plantings showed 80 per cent 
curly leaf on July 23, near Chualar, about 20 miles from the ocean, 
while beet seeds which germinated after May 1, showed only 3 per cent 
blight on August 5. The same condition occurred in the San Juan 
Valley; where, on one side of the river, March and April plantings 
were destroyed by curly leaf; while, on the opposite side of the river, 
late plantings produced a good crop. 
It is evident that the date of planting has been the cause of curly leaf 
trouble in the fog belt of the Salinas Valley. Planting should be dis¬ 
continued from March 1, until after the spring dispersal frcm Gonzales 
to Monterey Bay. In the fog belt from Chualar to Monterey Bay the 
soil is usually too wet and the weather too cold and foggy to plant early. 
