across, contains several thousand pear trees, and is separated from commercial 
pear-growing ■ areas , "by a considerable distance* (ly.M. Wadley, -Bureau of 
Entomology and Plant . Quarantine., U. S. D. A. ) ; •• 
C0MST0CK‘S MEALYBUG • • % 
Comstock's mealybug on apple is receiving considerable attention in Vir- 
ginia where it causes a black sooty mold to grow on the fruit., T\iis condition 
b.scame evident in 1934 and since that time the in&ect has spread and the fungus 
is causing serious injury,- • In 1939 it was very injurious. Since, the insect, 
was first identified by H, Morrison ap appearing in the United States in Indiana 
and Maryland in 1916 , it has spread to include Massachusetts, Connect! cat, Now 
York, New Jersey, Pennsylvania, Virginia, West Virginia, South Carolina, Florida, 
Ohio, Michigan, Iowa, Mississippi, Louisiana, and California. We have question- 
able records from North- Dakota and Washington, It was reported for the first 
time in 1938 in Ohio and Michigan, and both States repotted Infestations again 
in 1939* The. inf es tat ion on apple in Virginia in 1939 was the most general that 
has been observed. There are three general areas, of infestation, the Crozet 
area, the Boanoke area, and the Winchester- .area, 
BEET LEAFHOPPER _ ’ .. : .... 
Above-normal, fall temperatures in 1937 > together with sufficient precipi- 
tation, permitted a good germination of. downy chess, Excessive, precipitation in 
March 1938 permitted a much more dense and widespread germination, resulting 
in excellent stands, of this nonhost in certain Russian- this tie areas. Dense 
stands of downy chess intermixed ^ith Russ ion-this tie, the most favorable summer 
host, reduces the suitability of such areas for reproduction of. large numbers- of 
leafhoppers. These summer host-plant conditions and a* small spring generation of 
leafhoppers were important factors in the production of a low fall population, 
September surveys of Russian- this tie areas in southern Idaho in 1938 showed the 
lowest beet leafhopper population recorded in the- last 5 years, although fall 
weather conditions before the first killing frost, which occurred throughout 
southern Idaho on October 18, were favorable for the complete development of a 
late- summer. or fall generation of the leafhopper. Late-fall and winter, host 
plants, such as green tansymustard, flixweed, and peppergrass, germinated freely 
as a- result of the precipitation during October and early in November; conse- 
quently, the comparatively snail number of loafhoppe rs produced during, the summer 
on Russian- this tie found suitable fall and winter. host plants and entered the 
winter under favorable conditions. The winter was mild and dry and, in general, 
was favorable for survival, . V • , ■ • 
Early spring surveys in the desert breeding areas showed,. the lowest popula- 
tion of overwintered leafhoppers since 1936* Poor survival of green tansymustard 
resulted in a very sparse growth of this important spring breeding host plant in 
most sections. The spring generation of beet leafhoppers in southern Idaho was 
very small, owing to the low population of overwintered leafhoppers and a scarcity 
of favorable host plants on which to reproduce., The initial movement of the spring 
generation into the cultivated. are a occurred on May 17 and the peak was reached 
on June l4. The number of leafhoppers in the spring movement in 1939 waB approxi- 
mately one-third as ldrge as in 1936, one- thirty-fifth as large as in 1937, and 
one- tenth as large as in 1938. Surveys .of commercial beanfields in July showed 
that curly-top injury, to beans was very light, ranging from 0 to 3»0 percent in 
the garden varieties and from'o to 1.0 percent in .the Great Northerns, a dry-bean 
