222 



INSECTS INJURIOUS JO VEGETABLES 



l)ut its surface is covered with minute gray scales, which give 

 it a nearly uniform gray appearance. The head, however, is 

 black, and there are three black impressed spots at the base 

 of the wing-covers. The snout is robust and rather strongly 



curved. The northern limit 

 of injurious occurrence of the 

 potato stalk weevil is reached 

 in Pennsylvania and New 

 Jersey in the East, and in Il- 

 linois and Iowa in the West ; 

 recently, however, the species 

 has been reported a pest in 

 Canada. Southward the insect 

 is found to Florida and Texas. 

 More often perhaps than 

 not, injury by this pest is at- 

 tributed to drought or blight. 

 Fig. 142.— Potato stalk weevil, a, Beetle; It is more conspicuous in sea- 



b, larva; c, pupa: d-, section of potato stalk r i 11 1 . 1 



opened to show larva and pupa in situ. ^O^S of prolonged drought and 



(7, i, c, Five times natural size; d, natural most severe on early varieties 



size. (Author's illustration, U. S. Dept. r , , rr^, , . . 



^ ) 01 potato. 1 he undermmmg ot 



the stalks by the larvae causes 

 them to wilt, and the wilting and the dying of the leaves is the 

 first outward manifestation of attack. When the insects are 

 present in the field it is often stated that the plants are "blighted." 

 The diseases of potato are apt also to be mistaken for the work 

 of the weevil, as in both cases the leaves look as if sunburned, 

 especially after the vines have been afTected for some time. Not 

 infrequently a field suffers from the combined effects of dry 

 weather, disease, and stalk weevil. 



This insect attacks nearly all Solanace?e growing within its 

 natural range. The list includes, besides potato, eggplant, horse 

 nettle, bull nettle, jimson weed, purple thorn apple, ground 

 cherry and, it is said, cocklebur. 



