Pests and Diseases 193 
form to pupae in autumn and the change to the beetle 
form takes place before winter, the beetles usually remain- 
ing in a quiescent state until their emergence the following 
spring.” ! 
Wireworms do not affect sugar-beets nearly so much 
as they do some other crops. They are always worse 
after sod, corn, beans, or potatoes. When once they get 
into the land, they are difficult to eradicate by ordinary 
treatments. Nothing put on the land will kill them with- 
out also injuring the soil. One of the best ways is to starve , 
them out by summer fallowing or by growing crops on 
which they do not feed. The elimination of trash from 
the field also helps. 
Flea-beetles and leaf-beetles (Chrysomelidae). 
Several small leaf-feeding beetles, known as flea-beetles 
and leaf-beetles, do considerable damage to sugar-beets. 
The most severe injury is to young beets when they have 
from two to eight leaves. Some of these insects cause in- 
jury both in the adult and larval stage. The beetles 
‘skeletonize the leaf by eating out the pulp between the 
veins. These insects are sometimes poisoned by the use 
of paris green, london purple, and paragrene applied dry 
mixed with flour and dusted on to the leaves. Arsenate of 
lead is an effective spray. Clean culture is also helpful. 
Grasshoppers. 
Grasshoppers are among the most common and the best 
known of crop pests. They eat almost all kinds of plants 
1 Chittenden, F. H., U. S. Dept. of Agr., Bur. of Ent., Bul. No. 
43. 
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