ENTOMOLOGY 197 



all wheat-stubble land is deeply turned under with the plow in the 

 fall or winter. The likelihood of serious infestation from neighbor- 

 ing grass lands is not great, although not to be ignored. (Farmers' 

 Bui. 132, U. S. D. A.) 



INSECTS AFFECTING CLOVER, GRASS, AND OTHER FORAGE CROPS. 



Clover Root-Borer. Undoubtedly the most destructive enemy 

 of clover is the root-borer, a creature which was unknown in Michi- 

 gan up to about twenty years ago, but which has now become well 

 distributed. Originally from Europe, the root-borer was accidentally 

 imported into America without the natural enemies with which it 

 had to contend in its native home. Here it has found the land of 

 promise and fulfillment. 



Usually the first acquaintance with this pest is made sometime 

 after the field has been cropped for one season. The field will not 

 look just right and a few plants will be pulled to see if the roots are 

 healthy. Affected plants are apt to break off at the level of the 

 ground. On examination the roots will be found to be tunnelled, 

 the cavities being blackened and often containing the tiny beetles or 

 the grubs, sometimes eggs will be found if the tunnels are examined 

 with a good lens. Further search is apt to reveal a good many plants 

 in the same condition. 



Seldom, if ever, does the root-borer work in clover plants before 

 they are a year old that is, one year from the spring following the 

 sowing of the seed. The first spring directly following seeding, the 

 roots are too small to attract them, and after that they escape until 

 tho following spring, owing to the habit of the beetle of migrating 

 only at the spring season, usually in early May. There is but one 

 generation each year. 



The winter is passed in the tunnel, for the most part, in the 

 adult stage. Migration occurs usually in early May, new fields are 

 attacked and tunnels made, so that by the latter part of May the eggs 

 are laid, packed away in the dead parts of the roots and covered up 

 with refuse. Toward the latter part of summer the larvae change to 

 pupae in the burrows, to become adult beetles by fall. Both larvae 

 and pupae feed on the substance of the roots. Mammoth clover suf- 

 fers most of all. Common Red clover (June clover) nearly as much 

 and alsike less. 



The beetles themselves are very small, being rather less than 

 one-eighth of an inch in length. They are reddish-brown in color. 

 The eggs are smooth and white, and the larvae are white with yellow- 

 ish-brown heads. 



We find one encouraging feature in tho whole situation, in that 

 the beetle never attacks until the plants are one year old. True, they 

 have not done much in the way of growing by that time, but they 

 have made a start and are ready to produce hay. During the season 

 after seeding, the field usually escapes with a minimum of injury, 

 but after that time there is apt to be trouble. We must bo content 

 with one season's crop of clover, instead of a succession of seasons of 

 clover meadow produced by re-seeding, as was customary before tlio 

 root-borer came. It forces us to keep up a short rotation with clover 



