INSECT ENEMIES OF WESTERN FORESTS 



29 



to pupae and new adults within a cell in the ground, where they 

 remain over winter, and emerge the following spring as full-grown 

 beetles. 



Figure 10. — Polyphylla crinita Lee: Adult beetle, eggs, and larva or white 

 grub. All x 2. (Drawings by Edmonston.) 



White grub damage can be largely prevented by cultural oper- 

 ations. New ground that is to be used for transplant beds should 

 be cultivated 2 or 3 years before planting, to allow for the emer- 

 gence of beetles already in the ground and to avoid new egg laying. 

 If the ground is thoroughly worked over with a rotary tiller about 

 the end of June and again about 3 weeks later, a high percentage 

 of white grubs will be killed and damage will be comparatively 

 light. Damage from white grubs in western forest nurseries has 

 not required any further control action than these preventive cul- 

 tural practices. 



ROOT WEEVILS 



In forest nurseries of the Pacific Northwest, and elsewhere 

 (106), the strawberry root weevil is one of the most serious insect 

 pests. Three species of Brachyrhinus, of which the most common is 

 the strawberry root weevil (B. ovatus (L.)), have been known to 

 damage roots of coniferous seedlings (57) . The adults are small, 

 brown, hard-shelled, wingless beetles about % inch long, with 

 head extended into a snout. When the adult weevils emerge early 

 in the summer, they migrate on foot, crawling everywhere, in 

 search of suitable places for egg laying. Eggs are laid on the 

 ground around the crown of plants, and the small, white, curled 

 grubs develop in the soil, where they feed on the roots of various 



