254 THE CANADIAN ENTOMOLOGIST 



agronomic advice, nor indeed is it a good entomological practice 

 in relation to such insects as the root aphis and root worm. 



For several years past our records have shown very little or 

 no injury to corn planted on ground which was in clover the pre- 

 ceding year, and not infrequently observant farmers have reported 

 this condition. The past year observations which are more con- 

 clusive and which corroborate the above statment have been made. 

 For instance, last fall at Cascade, Iowa, we collected grubs behind 

 a plow which circled a field, two-thirds of which bore a crop of 

 tim.othy and one-third a good stand of alsike clover. As the plow 

 turned up the soil in the timothy area the grubs were very abundant 

 but as soon as the clover sod was reached, scarcely a grub could 

 be found. Further, at one corner of the clover area the clover 

 had died out, apparently because the lime had washed away, and 

 the small patch had grown up in smartweed, sorrel and the like, 

 and here the grubs were again abundant as in the timothy end of 

 the field. At Richland, Michigan, a farmer limed his field pre- 

 paratory to sowing clover, but left one drill row unlimed to satisfy 

 himself on the value of the lime. Last spring when the May- 

 beetles were abundant at Richland there was an excellent stand of 

 red clover over the entire field excepting the unlimed strip which 

 grew up to grass and timothy. An examination this spring re- 

 vealed 30 to 40 grubs to the square yard in the unlimed strip, that 

 is, where the timothy was growing, while in the rest of the field 

 where the clover had made a good growth only 1 or 2 grubs to the 

 square yard were to be found, and in digging a trench from the 

 clover into the timothy one knew as soon as the timothy strip was 

 reached by an abundance of grubs. All of these facts give us 

 conclusive evidence that May-beetles will not deposit their eggs 

 in numbers in ground which has a stand of clover which covers 

 the ground, probably because the clover mats over the surface 

 and makes it difficult tor the beetles to make an entrance. 



The natural conclusion is to substitute clover for timothy in 

 the rotation and to follow corn on clover ground, especially the 

 year following an abundance of May-beetles. The growing of 

 clover in place of timothy is a practice which has been recom- 

 mended and advised by agronomists, but in most sections where 



