2 SOME INSECTS INJURIOUS TO TRUCK CROPS. 
by negro children. Afterwards the vines are dusted with land 
plaster and Paris green, applied by shaking a burlap sack, filled with 
the mixture, over the plants which seem to be the worst affected. 
As a result of the imperfect application of the arsenical the crop is 
only partially freed from the insects and, as the application is never 
made until the injury of the first generation or brood of larvee becomes 
very apparent, the vines are not entirely free from the injurious 
effects of untimely defoliation. In many places, also, the plants are 
seriously checked through the injury caused by the beetles, which 
entirely defoliate the young shoots as they are coming through the 
earth, in many cases eating them off level with the ground or below 
the surface. Seed potatoes which remain partially above ground are 
also rapidly devoured by the beetles. 
After the larvee or young commence to appear, the plants showing 
the greatest injury are treated with the dust, this application usually 
being held sufficient for some time. The land-plaster application is 
from three to four times as expensive as a Paris-green spray of equal 
strength, and in several cases in the Norfolk region the application of 
the unnecessary plaster to the already acid soil has produced a state 
of disease in the cabbage crop following the potatoes which has 
lessened the production to a considerable degree. In the case of a 
spray this acidity is not imparted to the soil and injury to cabbage is 
thus avoided. 
In that part of Virginia immediately adjacent to the District of 
Columbia the growing of potatoes is less important commercially 
than in the Norfolk region, and while the beetle is a serious pest 
always, the smaller acreage of potatoes grown renders the control of 
the insect much more easily accomplished. 
LIFE HISTORY AND HABITS. 
In general, the life history of the Colorado potato beetle in Vir- 
ginia agrees with the description already published by Doctor Chit- 
tenden.* In specimens reared in confinement in the insectary at 
Washington and in outdoor cages at Norfolk in 1908, three genera- 
tions or broods were reared during the summer, and very young larvee 
have been seen on tomato at Norfolk as late as the latter part of 
August and the 1st of September. The period of xstivation which 
generally follows the second generation in this species was shortened 
to four days in the beetles which were carried through the stages at 
Norfolk. These beetles issued from eggs collected from the first 
generation May 26. The larve pupated June 20 and issued as adults 
June 28. After feeding until July 3 the beetles burrowed into the 
soil, forming cells, where they remained for a period of four days, 
a Cir. No. 87, Bur. Ent., U. S. Dept. Agr., 1907. 
