256 



INJURIOUS \ND BENEFICIAL INSECTS OF CALIFORNIA. 



about 1-L'o inch long. 



Fig. 246. — The California 

 i worm Brom us ob- 

 scurus i Linn. t. Adull 



■ times. < A i 

 tion, Mo. Bui. Cal. Hort. Com. I 



of the body. The antenna' and Legs are usually black, but are some- 

 times brown instead. The eggs are elongated, yellowish-white and 



The full-grown larva' are white with brown 

 heads, { inch long-, and curved towards the 

 ventral surface in the shape of a crescent. 

 The pupae are white and slightly larger 

 than the mature beetles. 



Life History. — The eggs are laid early 

 in the spring, usually in clusters of from 

 one to twenty-five, in cracks beneath the 

 bark on the trunks of the vines, anywhere 

 within six inches above the surface of the 

 mound. They hatch in from eight to ten 

 days and the young larvae immediately seek 

 the roots of the vines. The smaller roots 

 are often entirely destroyed and large 



patches of bark removed from the larger ones. They continue to 



feed underground until fall, when they become full-grown, and pass 



the winter in small earth- 



ern cells, transforming 



into pupa- in the spring 



and emerging as adults 



about two weeks later. 



The larva' and pupae 



are usually located with- 

 in a radius of fifteen 



inches from the trunks, at 



a depth of two feet or 



less. The adults begin to 



issue about May and feed 



upon the foliage. They 



begin to lay eggs in June. 



There is but one brood a 



year. 



Nature of Work. -The 



, .• i j Fig. 247. — Grape leaf, showing the characteristic 



larva 1 may entirely ae- work of the California grap worm. Bromius 



Stroy the 'young rootlets obscurus .Linn... (Alter Cal. Hon. Com.. 

 or patches of bark on the larger roots. The adults eat very character- 

 istic long, narrow holes in the leaves, as shown in Fig. 247. 



Distribution. — This beetle occurs throughout the northern and cen- 

 tral parts of the State, being reported as far south as Tulare County. 



Food Plants.— Apparently all varieties of grapes are attacked by 

 this pest. The fireweed (Epilobium angustifolium) is. according to 

 Dr. Van Dyke, the native host of the beetle. The leaves of Saxifraga 

 l>i lhil(i u,] are also attacked. 



Control.— Thorough cultivation, close to the bases of the vines, 

 during the summer and winter will destroy many of the grubs and pupae. 

 The attacks of the adults may be held in check by repeated applications 

 of arsenical sprays. Jarring them upon sticky boards or into recep- 

 tacles containing oil is also recommended. 



' c 'Rnmig.in, E. J., Mo. Bui. Cal. Hort. Com., II, pp. 585-586, 1913. 



