8 THE SUGAE-BEET WIREWORM. 



Life history and habits — Continued. 



The adult — Continued. Page. 



Variation in the color of beetles 34 



Feeding of the adults, and food plants 35 



Styles of rearing cages used 36 



Duration of life under varying conditions 37 



Length of time adults can be submerged 38 



Effect of temperature on the adults 39 



Ability of the adults to withstand unfavorable conditions 40 



Method and time of mating 40 



Actions of the adults after mating 41 



Oviposition 42 



Approximate length of the life cycle 42 



Seasonal history 42 



Beetles from emergence to hibernation , 42 



Hibernation 43 



Mortality during hibernation 43 



Gradual emergence from hibernation 43 



Secondary hibernation 44 



Occurrence of beetles in the field 45 



Effect of food in the field on dissemination 45 



Other factors governing dissemination 46 



Natural control 46 



Enemies and checks to the beetles 40 



Enemies and checks to the larvae 48 



Fungi affecting the pupae and eggs 49 



Remedial measures 50 



Historical 50 



Tests of suggested remedies against the sugar-beet wireworm 50 



Attempts to destroy the adults with poisoned baits 50 



Fall plowing for destruction of the pupae 51 



Experiments with deterrents against the wireworms 52 



The use of potassium cyanid against the wireworms 59 



Experiments with poisoned bait against the wireworms GO 



Experiments with guano fertilizer 61 



Protection of beets by early planting 61 



Clean culture against the adults Gl 



Summary 64 



Bibliography 64 



Index 65 



