59 



room tight and place on the tubers a dish containing \y 2 to 2 Ibs. 

 of carbon bisulphide for each 1000 cubic feet of space enclosed, and 

 repeat the dose as often as moths appear, usually four or five times 

 will not be too much to exterminate them. The bisulphide gas will 

 penetrate the sacks and save the crop if the bin is tight. The gas is 

 explosive ; keep fire away from it. 



Infested potatoes should never be used for seed, nor infested 

 land used again for potatoes the next year. Waste potatoes should 

 be burned, not buried, and if fed to hogs, cooked or soaked well 

 first. 



Alfalfa Weevil (Phytonomus posticus) Adult. 

 Six times actual size. 



Alfalfa Weevil 



(Phytonomus posticus) 



This pest, which we have so far succeeded in keeping out of Cali- 

 fornia, is a very serious menace to the alfalfa grower as evidenced 

 by its work in Utah, Idaho and Wyoming, where they often ruin 

 the first two crops and seriously injure the third. 



The insect is one of the snout beetles, when mature is from one- 

 eighth to three-sixteenths of an inch long, brown, flecked with gray 

 or white ; growing older, it becomes darker until almost black, still 

 with the gray mottling. They are very active and ready to fly, 

 which they can do for long distances. 



The larva when hatched is very small, white and footless, later 

 they become green, are always curled up, and when they pupate, 

 form a spherical cocoon of coarse fibers, from which the adult 

 emerges. In May they are in all stages of development on the 

 plants, and the adults will live a year. The adult shows up on the 

 first cutting of alfalfa in the spring and soon begins depositing eggs 

 in the stems of the plant to the number of two or three hundred. 

 The larva soon hatch out, very small at first, getting to work at 

 once on the plants and leaves. As summer arrives, they hibernate 

 under alfalfa, weeds, rubbish of all kinds, pupate in their cocoons, 



