8 THE SUGAE-BEET WIEEWOEM. 
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 var\dng 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 
O^iposition 42 
Approximate length of the life cycle 42 
Seasonal histoiy 42 
Beetles from emergence to hibernation 42 
Hibernation 43 
Mortality during hibernation 43 
Gradual emergence from hibernation 43 
Secondaty 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 46 
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 wire worm 50 
Attempts to destroy the adults with poisoned baits 50 
Fall plowing for destruction of the pupas 51 
Experiments with deterrents against the wire worms 52 
The use of potassium cyanid against the wireworms 59 
Experiments with poisoned bait against the wireworms 60 
Experiments with guano fertilizer 61 
Protection of beets by early planting 61 
Clean culture against the adults 61 
Summary' 64 
Bibliography 64 
Index 65 
