10 THE SUGAR-BEET WIRE WORM. 



Plate XXI. Clean culture against the sugar-beet wire worm. Natural method 

 of clearing off beet tops, by pasturing cattle in the field. 



which has been inclosed by a temporary fence 60 



XXII. Clean culture against the sugar-beet wire worm. Collecting the 

 beet tops in piles and hauling them from the field as food for 



stock 60 



XXIII. Conditions favoring the sugar-beet wireworm. Fig. 1. — Beet 

 fields separated by a strip of alfalfa. Fig. 2. — Field of alfalfa 

 adjoining field of sugar beets 60 



TEXT PIGURES. 



Fig. 1. The sugar-beet wireworm (Limonius cnlifornicus). Details of larva. 15 



2. Map of California showing counties from which the sugar-beet Avire- 



worm has been reported 17 



3. Injury by sugar-beet wireworm to field of sweet corn, Dominguez, Cal . 18 



4. Diagram showing the period eggs of the sugar-beet wireworm were in 



the soil, with temperature; season of 1912, Compton, Cal 19 



5. Janet ants'-nest plaster-of-Paris cage, used in rearing sugar-beet 



wireworms 22 



6. A sugar-beet wireworm devouring one of its own kind; to illustrate 



cannibalistic habit 25 



7. Diagram showing length of life of sugar-beet wireworm without food . . 28 



8. Screen cage used in observing oviposition of adults of the sugar-beet 



wireworm under field conditions 36 



9. Diagram of beet fields, to illustrate the effect of clean culture in 



reducing injury by the sugar-beet wireworm 63 



