INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA. 



303 



Control.— The attacks of the weevil in question have so far been few 

 and of short duration and there has been little need of control. If 

 they do become serious, arsenical sprays should be applied to the 

 foliage as soon as the adults appear in April. Quantities of weevils 

 may be easily jarred into sheets and destroyed. 



THE POTATO STALK BORER 217 



Trichobaris trinotata Say (Family Cureulionid.-e) 



(Figs. 297-300) 



Description. — The beetles average j inch in length and T V inch in 

 width. The ground color of the entire body is 'dull-black, but the body 

 is covered with light-gray 

 scales, which are sparsely ar- 

 ranged on the dorsum, giving a 

 slate-gray appearance, and so 

 thick on the ventral surface as 

 to make it appear light-gray or 

 silvery. At the union of the 

 prothorax and wing covers, and 

 on portions of each, there are 

 three black spots, where the 

 scales are wanting, one in the 

 middle and one at the margin 

 on each side. Other parts 

 which are black, because of the 

 lack of scales, are the head, end 

 of snout, antenna 1 , a small area 

 on the ventral surface of the 

 abdomen near the anal end, the 

 ventral sides of the prothorax 

 and the hind coxa?. The eyes 

 are also black. The collar or 

 front margin of the prothorax 

 is orange-yellow. The head is 

 very small with curved snout 

 which is as long as the pro- 

 thorax. The eggs are very 

 small, oval and pearly white. 

 The larva? are white or yellow- 

 ish with light brown bends. 

 They are legless and bent, as 

 shown in Fig. 298. The back and 

 sides are rough because of the 



2,7 There is some question regarding the identification of this species. Dr. Van Dyke 

 has made very careful comparisons with other species and finds it more like the above 

 species than any other. In fact, the only noticeable difference is in size, the California 

 form being a little larger than that of the Middle States. Chittenden has recorded 

 Trichobaris mucorea as a tobacco pest in this State (Bui. No. 38, n. s. Bur. Ent. U. S. 

 Dept. Agric, pp. 66-70, 1902). 



Matthew Cooke refers to the potato stalk borer as attacking the Jimpson weed in 

 the southern part of the State (Inj. Ins. Orchard. Vineyard, etc., pp. 206-307, 1883). 



From both of these references it will be seen that there is some confusion regarding 

 the two species. Probably the insect attacking tobacco is the potato stalk borer and 

 without doubt the beetle referred to by Matthew Cooke is Trichobaris mucorea Lee. 



Fig'- 297. The potato stalk borer, Tricho- 

 baris trinotata Say. Larva* and their work in 

 green potato stalks. Natural size. (Original) 



