Alfalfa in Kansas. 



373 



Methods of Control. 



NATURAL ENEMIES. The white grubs fall prey to birds whenever they 

 are exposed. Large numbers of the grubs and adult beetles are consumed 

 by skunks. Many of the grubs are devoured by moles. A small per- 

 centage of the grubs are killed by parasitic fungi. Sometimes a large 

 per cent of the grubs are destroyed by parasitic insects, chief among 

 which may be mentioned a small wasp-like insect (Tephia inornata 

 Say.). 



ROTATION. Allowing the land to remain in alfalfa year after year is 

 conducive to the increase of the grubs. If the grubs have become well 

 established in the alfalfa there is no practical method of control, except 

 rotation. A badly infested field should be thoroughly pastured with 



FIG. 318. White grub (Lachnosterna negosa). Adult beetle and larva; 

 natural size. (After Forbes.) 



times 



hogs during the summer, allowing them to root it over. In the fall or in 

 the early spring it should be plowed deep and thoroughly harrowed. 

 This will not only kill large numbers of the pupae by breaking open the 

 pupal cells and exposing them to the weather, but it will also expose 

 the grub to birds and other enemies. Chickens and turkeys following 

 the plow will catch a large number of grubs. 



In pasturing alfalfa with hogs it should be remembered that the giant 

 thorn-headed worm, one of the serious intestinal parasites of the hog, 

 infests the white grub. Inasmuch as the grubs must obtain this para- 

 site from infested hog feces, and since the life of the grub is three years. 

 it is plain that hogs may be safely used to clean the land if it has not 

 been pastured with hogs at any time in the previous three years. 



