i84 



AN ECONOMIC ENTOMOLOGY. 



of the injurious species. The noteworthy points are the early 

 appearance and oviposition of the beetles, the two- or three-year 

 life of the larva, and the pupation and change to adult in fall ; 

 all of which must be considered in the methods of treatment to 

 be adopted. 



The direct application of insecticides is usually impracticable, 

 and the texture of the larva is so dense that most contact poisons 

 are of little or no avail, salt in large quantity having proved the 

 most effective. Stomach poisons are not easily applied, but on 

 an experimental scale it has been found that sweetened dough 

 placed beneath the surface attracts them, and this can be poi- 

 soned and used as a trap. Practically, methods of cultivation 

 calculated to avoid injury are most satisfactory. Grass land 

 known to be infested should be plowed in fall, and while this will 

 not destroy any large proportion of the larvae, it will kill most of 

 the pupae and beetles then in the ground, so if the practice be 

 continued for a series of years the insects will be gradually run 

 out. Wherever feasible, crimson clover should be used as a 

 sod crop, as this is sown in late summer after the beetles have 

 oviposited and may be harvested and plowed under shortly after 

 the beetles have laid eggs, practically preventing the develop- 

 ment of the larvae, especially if a crop little or not at all subject 

 to wire-worms follows the clover. In fact, frequent change of 

 crops is a most satisfactory measure if the land be not allowed to 

 remain in grass more than one year, and if corn or potatoes do 

 not directly follow the sod. In light soil the salty fertilizers ex- 

 ercise a very beneficial effect when properly applied, and some- 

 times an advantage may be gained by keeping the land in sod as 

 long as possible, where grass is needed as a crop. When it has 

 " run out," plow in fall ; in spring, after cultivating and prepar- 

 ing for the new crop, fertilize heavily, using kainit for potash and 

 nitrate of soda, so far as possible, for nitrogen. At least one 

 thousand pounds of kainit per acre should be used, and this 

 seems exceedingly disagreeable to the insects at all ages, and 

 fatal to the younger forms. Conditions vary so much in different 

 parts of the country, and rotations are so diverse in character, 

 that it is impossible to suggest any course that will be universally 

 appHcable, except the fall plowing. The suggestions above made 

 should be sufficient, however, to guide the intelligent farmer in 



