198 INSECTS AFFECTING FIELD CROPS 



most of them have become full grown and pass into the pupal 

 stage. The second brood of beetles appears in the fall, not leaving 

 the plant, however, until the following spring. The dispersal of 

 these insects takes place in spring; the beetles then fly about 

 seeking uninfested plants. 



Injury. The tap roots of Mammoth and Common Red Clover 

 are sometimes seriously injured by this insect, while alsike is not 

 so subject to attack. Since alfalfa in Europe has been injured, we 

 may expect ultimately to have the same trouble here. The first- 

 year clover is exempt from attack on account of the small size of 

 the roots. 



Control. Wherever possible, summer fallow the soil as soon 

 as the first cutting of the crop is removed. This dries out the roots 

 and starves the larvae. Fields of clover should not stand in clover 

 more than three years. Scientific rotation of crops is also desirable. 



The Clover Hay Worm* (Hypospygia costalis Fab.). This 

 caterpillar attacks hay in the stack. It interweaves the hay with 

 white silken webs mixed with black particles of excrement, giving 

 the hay an appearance of being mouldy, and reducing much of it 

 to chaff. Such hay is not attractive to stock. 



Description. The caterpillar is three-fourths of an inch long 

 when full grown. It is dull brown in color, and may be found in 

 barns throughout the winter, pupating in the spring. The moth 

 is rather striking in appearance, with whig expanse of one inch. 

 The silky wings are tinged with purple above, margined with yel- 

 low, and fringed with orange. There are two large, conspicuous, 

 golden spots on each fore-wing. 



Control. Old hay is more apt to be attacked than the new 

 crop. Therefore, farmers are advised not to keep hay over a 

 second year. Feeding the hay to stock will cause the young cater- 

 pillars in infested hay to perish before the new crop comes in. 

 Hay-mows should be cleaned out each spring, and one should never 

 place new hay on top of the old. It is suggested, further, that new 

 stacks of hay be built at some distance from the old. All refuse 

 from old stacks or the bottom of the hay-mow should be burned. 

 Stacks should be raised above the ground on a foundation of logs 

 or rails so that the bottom may be kept fairly cool and dry. These 

 caterpillars are more active where there is warmth and moisture. 

 It is further suggested that hay be salted on the bottom of the 

 stack or mow, using about two quarts of salt to every ton of hay. 



Blister Beetles (Macrobasis unicolor Kby. and Epicauta penn- 



