INSECTS INJURIOUS TO CLOVER AND ALFALFA 191 



first year as the roots are not large enough to accommodate the 

 insects, and it is not until the second year that the plants are 

 destroyed. 



Control. The only effective means of control suggested is 

 summer fallowing as soon as the hay crop has been removed. 



FIG. 160. Present known distribution in the United States of the clover-root 

 curculio. (After F. M. Webster, L. C.) 



The field should then be plowed up at once, before the larvae 

 have transformed to pupae, so that the hot sun, and dry winds, 



FIG. 161. Stages of the clover-root curculio. (After Webster, L. C., from 

 Wildermuth): a, adult; b, larva; c, pupa. 



will dry out the roots of the clover and thus starve the larvae, 

 thereby preventing their developing and migrating to other 

 fields. Clover fields should not be allowed' to stand over two 



