WIEE WORMS ATTACKING CEREAL AND FORAGE CROPS. 33 



Webster carried on experiments at Cedarville, Ohio, in 1894 

 to determine the effectiveness of kainit as an insecticide. The fer- 

 tilizer was applied at the rate of 500 pounds to the acre without 

 any effect whatever. He also carried on a series of experiments at 

 La Fayette, Ind., in 1889, to test the efficiency of an often-recom- 

 mended substance — table salt. Pots were used in these experiments, 

 and table salt applied to the surface and washed in with water. 

 Three dosages were used at the rate of about 500 pounds, 1,000 

 pounds, and 25,000 pounds per acre, respectively, and in no case were 

 wireworms killed by the application. 



The Maine experiment station has tried a patented preparation 

 composed largely of slaked lime, a " soil fungicide," and tobacco 

 dust, applied to the hills in cornfields infested with wireworms, and 

 has found all of these treatments quite useless. Experiments l with 

 chlorid of lime, gas lime, chlorate of potash, bisulphid of carbon, 

 crude petroleum, kerosene, and emulsions of crude petroleum and 

 kerosene, applied to the soil, have demonstrated that none of these 

 substances is of practical value in destroying wireworms. However, 

 the use of petroleum products as soil sterilizers is suggestive, and will 

 be further investigated. 



Mr. J. J. Davis - has found that a soil f umigant highly recom- 

 mended by some English entomologists is quite useless in combating 

 Limonius confusus. 



CULTURAL METHODS. 



The third group of remedial measures — cultural methods — is the 

 only one which so far has been actually proved to be of practical 

 value. 



Flooding land where irrigation is practiced would be of little 

 avail unless long continued, as we have records of severe outbreaks 

 of wireworms on land in Indiana that is annually overflowed by 

 the rivers. Fall plowing is of but little use in combating these 

 insects. The cornfields so severely attacked by the wheat wire- 

 worm at Bridgeport last year had been plowed in the spring. The 

 garden patch, however, was fall plowed, and potatoes on this patch 

 were absolutely destroyed by wireworms. Another piece of fall- 

 plowed land on another part of the farm planted to corn was 

 practically free from worms, which illustrates how easily faulty 

 conclusions can be arrived at, with insufficient data. Mr. O. A. 

 Johannsen and Miss Edith Patch record observations made at Mon- 

 mouth, Me., in 1911, wherein a field was plowed after the ground 



1 Comstock, J. H., and Slingerland, M. V. Wireworms. N. Y. Cornell Univ. Agr. Exp. 

 Sta., Bui. 33, November, 1891. 



2 Davis, J. J. Insect notes from Illinois for 1909. In Jour. Econ. Ent., v. 3, No. 2, 

 p. 182, April, 1910. 



