The Beet Leaf-Beetle and Its Control. 5 
The beet leaf-beetle, under normal conditions, subsists upon the 
weeds mentioned, which grow in waste alkali soil, and as long as 
there is a supply of these plants sugar beets are little damaged. In 
the spring, before the weeds are abundant, overwintered beetles often 
infest small young beets, completely destroying them. Later the 
insects develop in such numbers on the weeds that the latter are killed. 
The insects then resort to sugar beets for food. Many hundreds 
of acres of beets are thus infested every year. (Fig. 6.) The beet 
leaf-beetle is injurious also because it acts as a carrier or distributor 
of the spores of the leaf-spot disease of beets.‘ 
The beetles cut large, irregular holes through the leaves of the 
sugar beet and the larvee do similar injury, eating pits in the leaves, 
frequently without cutting through. 
Fig. 4.—Map showing distribution of beet leaf-beetle. Large dots show injurious 
distribution ; circles, innoxious localities. 
When mature the larve leave the plants, burrow into the soil to 
a distance of half an inch or two inches, and form cells in which 
they transform to pupe and then to adults. 
LIFE HISTORY. 
In the Arkansas Valley in Colorado and in regions having a simi- 
lar temperature two generations or broods and a partial third brood 
are produced each year. The beetles pass the winter on the sur- 
face of the ground in alkali areas under tufts of grass, heaps of 
dead weeds, and other rubbish, a favorite location for this purpose 
being under tufts of “tickle grass,”* a habit which may be utilized 
to advantage in controlling the pest. 
* Cercospora beticola. 
© Panicum capillare. 
