276 FIELD CROP PRODUCTION 



in summer or early fall. The rate of seeding varies from 

 12 to 20 pounds per acre, 15 pounds being considered an 

 average seeding. 



FUNGOUS DISEASES AND INSECT ENEMIES OF CLOVERS 



277. Common enemies. — The clovers are not usually seri- 

 ously affected by fungous diseases, although leaf spot and leaf 

 rust and root and stem rot sometimes cause serious injury. The 

 entomologists list almost a hundred insects that do more or less 

 injury to the clovers. Many of them, however, are not widely 

 distributed, and the injury they do is comparatively small. 

 The three most common and injurious enemies are the clover 

 root-borer, the leaf weevil, and the seed midge. 



278. Clover root-borer. — The clover root-borer is a small, 

 black beetle that lays its eggs in May or June in cavities in the 

 crown of the plant or down the side of the roots. The eggs 

 hatch and a small grub-like larva burrows into the roots, eating 

 out great cavities and greatly weakening the plant. The larva 

 changes to the pupa stage, from which the adult beetle emerges, 

 but it remains in the root of the clover until spring, when it 

 comes out to lay its eggs. The most effective means of control- 

 ling this insect is to plow the field as soon as the hay has been 

 removed, thus depriving the lar^'ue of their food, causing them 

 to starve. The root-borer attacks chiefly red clover and mam- 

 moth clover, but it also injures alsike clover and alfalfa. 



279. The clover-leaf weevil. — The presence of this insect 

 in a clover field may be detected by the large, round notches 

 which are eaten in the edges of the leaves ; the larvae and adults 

 may then be found hiding at the base of the plant under leaves or 

 rubbish. Both the larvffi and adults are shy creatures, working 

 almost entirely at night, and if by chance they are found at 

 work during the daj', they immediately cease their activities and 

 drop from the plant to the ground as if dead. The adults are 

 stout, brown colored beetles with a strong snout. They lay 

 their eggs in early fall on the plant or in the debris near its base. 

 The larvfE, which at first are white, change later to a dark green 

 color, and become partly grown before winter. They remain 

 dormant during the winter, and when spring comes, they again 



