INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



2S7 



is spent there, the weevils emerging at will by cutting a circular hole 

 in the side. The adults of the first brood immediately begin egg-laying 

 upon the pods, as did the hibernating females in the field, but if in 

 storage bins or sacks the eggs are 

 laid upon the outside of the beans 

 or in old burrows previously made 

 in them. They thus continue to 

 •breed throughout the entire sum- 

 mer and winter if the weather is 

 not too cold, many generations 

 appearing each year. Under ordi- 

 nary conditions, the life cycle lasts 

 from twenty-one to eighty-one 

 days ; the egg stage from five to 

 twenty days ; the larval stage from 

 eleven to forty-two days ; the pupal 

 stage from five to eighteen days. 2 "* 



Nature of Work. — The small 

 round holes in the beans, as shown 

 in Fig. 279, indicates the presence 

 of this pest. Practically the entire 

 contents of the beans may be de- 

 voured. From one to fifteen, or even more, weevils may attack a single 

 bean, depending upon the size of the host. 



Distribution. — This insect is generally distributed throughout the 

 State, and is particularly troublesome in the central and southern 

 counties, where small beans are raised, and also in the storehouses 

 throughout the entire State. 



Foods.— Nearly all varieties of beans are attacked by this weevil, 

 though the small white and brown varieties are preferred. Limas are 

 only occasionally affected. Peas are also included as hosts. 



Control. — The first step in the control of this pest is to harvest Ihe 

 beans just as soon as possible, for those left in the fields are sure to 

 become largely infested. If any of the insects are discovered the beans 

 should be thoroughly fumigated with carbon bisulfid before they are 

 stored, and if weevils appear in the bins or sacks fumigation should be 

 resorted to at once. 



Fig. 280. — Adults of the bean weevil, 

 Acanthoscelides obtectus (Say). Enlarged 

 three times, i ( iriginal) 



THE PEA WEEVIL 



Bruchus pisorum Linnaeus 2 ? 8 

 [Laria pisorum (Linnaeus) j 208 



(Figs. 281, 282) 



Description. — The weevils are about J inch long, brownish-black in 

 color, with well defined light spots on the wing covers and a distinct 



2M Bul. No. 8, n. s. Bur. Ent. U. S. Dept. Agric, p. 43. 18!)7. 



2or, The pea weevil greatly resembles the broad-bean weevil, Bruchua ruftmanua lior. 

 The principal differences are given by F. H. Chittenden in the following tabular form: 

 Posterior femora acutely dentate ; thorax broad ; pattern of elytra well 



denned; pygidium with a pair of distinct apical black spots pisorum Linn. 



Posterior femora obtusely or obsoletely dentate; thorax narrow; pattern of 

 elytra more or less suffused ; pygidium with black apical spots kicking 



' or illy defined -pifimnnus i Boh 



20fi Because of confusion and the apparent unsoundness of the generic name, Lurm 

 it has been dropped in the revision. See footnote 203. 



