THE CANADIAN ENTOMOLOGIST 255 



the grubs are destructive the advice has not beein followed. Farm- 

 ers, as a rule, tell us they cannot grow clover in northern Illinois, 

 southern Wisconsin and similar latitudes because of winter kiUimg. 

 On the contrary thoroughly competerl't authorities inform us that 

 if the land is properly prepared for clover the danger of loss by 

 winter killing is of little consequence, and that agriculture would 

 be greatly improved in these sections if it were possible to secure 

 a greater acreage of clover to replace the now large acreage of 

 timothy. With the knowledge we now possess with regard to the 

 importance of clover in the rotation as a means of preventing white 

 grub injury it is not unlikely that it will have some influence in 

 reducing the timothy and increasing the clover acreage in the white 

 grub districts, and in this way in part compensates for the losses 

 which have resulted within the past ten years. 



A rotation which we have recommended in the past for the 

 white grub territory of northern Illinois and southern Wisconsin 

 and similar latitudes and which is approved by the agronomists 

 is oats or barley, clover and corn. If oats or barley are on the 

 ground the year of the May-beetle flight it will contain many grubs 

 but since either will be followed by clover which is little injured by 

 white grubs, no harmful results will follow. If the field bears a 

 good stand of clover during May and June of the year May-beetles 

 are abundant, few or no eggs will be laid in the ground and it can 

 be safely followed by corn, while if the field is in corn the year the 

 beetles are abundant, few eggs will be laid if the field is kept culti- 

 vated during the flight of the May-beetles, as it naturally should 

 be, and further even should there be eggs laid in the corn ground 

 as there occasionally are when the field is alongside a timber lot, 

 the ground would be planted to oats or barley the following year 

 according to the rotation suggested and these grains are little 

 injured by grubs. 



These few facts regarding the role of clover in the rotation to 

 prevent white grub losses are brought together not only to empha- 

 size the entomological importance of this crop, but also to show 

 again the intimate relation between the study of soils and crops 

 and field crop entomology, and the importance of a more intimate 

 correlation of the two subjects. 



