
iS 
of the decrease of fat content by beet leafhoppers in migration (Monthly 
Letter No. 218), now states: "Through the cooperation of W. A. Shands, 
of the Grand Junction, Colo., laboratory, collections have been taken of 
dispersing E. tenellus at various points between the extensive breeding 
areas near Phoenix, Ariz., and the Grand Junction beet-growing district. 
These collections were submitted to this laboratory for fat determinations. 
The determinations show a progressive decrease in total fat content 
roughly proportional to the distance from the breeding area, the results 
in general being comparable to the findings previously reported for the 
Mea territory for 1932." 
Control for black slugs on tobacco.--J. U. Gilmore, Clarksville, 
Tenn., reports: "A 5-acre field of tobacco was attacked by black slugs, 
Limax sp. (?). Our recommendation of 1 part Paris green and 30 parts 
of lime dusted on the crop at the rate of 4 pounds per acre was very 
effective in controlling this new pest. This pest has been reported in 
the Carolinas as attacking plants in the tobacco seed bed but we believe 
that this is the first instance of serious attack in the field. These 
slugs were present to the extent of 10 or 12 to the plant in some parts 
of the field and had not been carried in from the plant bed, which was 
uninjured. The paris green in the recommendation was for the flea bee-— 
tiles present." 
Derris dust effective against imported cabbage worm.--C. F. Stahl, 
maneord, Fla., states that "Against Ascia rapae L., rotenone 1.6 percent 
at 1 to 200 and rotenone 5 percent at 1 to 800 did not appear to be 
Suericiently toxic, either as a contact or a stomach poison. The use of 
derris dust (3 percent rotenone), 1 part in 4 parts inert carrier, gave 
very good kill, even without the addition of pyrethrum powder. This 
combination having approximately 0.6 percent rotenone gave better re-— 
sults as a contact dust than did a proprietary cube dust supposed to 
have the same rotenone content. Hellebore dust failed to give a satis— 
factory kill. 
FOREST INSECTS 
More on the southern pine beetle.—-The outbreak of Dendroctonus 
frontalis Zimm. in the more northern limit of its range (noted in the 
March, 1933, Monthly Letter) seems to be increasing in severity, a re- 
examination in May of 8,000 acres of virgin pines near Fairfax, Va., 
indicating population of beetles in the bark of these trees nearly 10 
times that normally found in such outbreaks, reports R. A. St. George. 
It is pointed out, however, that such overcrowding of the beetles may 
result in the destruction of their progeny and thereby check the out— 
break. An examination on June 2 indicated that beetles had emerged from 
the trees that had previously been heavily infested and were establishing 
Similar crowding in the trees subsequently attacked. Unless a natural 
control comes, as indicated, artificial control will be necessary in 
order to save the remaining timber in this and similar tracts. 
