THE COLEOPTERA 



137 



The Plum Curculio (Conotrachelus nenuphar Herbst). — This Insect 

 is a native of the United States and formerly fed upon the wild plum and 

 thorn fruits, but now also attacks cultivated plums, prunes, cherries, 

 nectarines, apricots, apples and peaches. It is found practically every- 

 where east of the Rocky Mountains, though in 

 the western portion of this area it seems to be of 

 less importance than elsewhere. The adult beetle 

 (Figs. 130 and 131) is small, being only about a 



Fig. 130. Fig. 131. 



Fig. 130. — Adult Plum Curculio (Conotrachelus nenuphar Hbst.), view from above. 

 About five times natural size. (Modified from U. S. D. A. Bur. Ent. Bull. 103.) 



Fig. 131. — Side view of adult Plum Curculio showing humps on the back. Enlarged 

 about five times. (Modified from U. S. D. A. Bur. Ent. Bull. 103.) 



fifth of an inch long, dark colored as a whole but mottled with gray 

 and brown. Its elytra are rough and on each is a black, shining hump 

 a little behind the middle. 



This pest spends the winter, or the colder months in the South, hiding 

 in any protected place it can find, particularly in the woods, in stone 

 walls or under leaves. It appears 

 about the time the plum buds open in 

 spring and feeds more or less on the 

 developing leaves. When the fruit 

 begins to develop, the beetles turn 

 their attention to it, feeding by cutting 

 a circular hole through the skin and 

 consuming the flesh beneath to a 

 depth about equal to the length of 

 the snout of the insect. They also 

 begin now to lay their eggs in the 

 young plums, cutting a hole in the 

 skin and then running the snout ob- 

 liquely into the flesh beneath. In 

 this cavity the egg is placed and it is 

 then pushed farther in by the snout. 

 The beetle next cuts a crescent-shaped 

 slit through the skin close to the 

 egg (Fig. 132) and carries this down through the flesh beneath the egg 

 which thus comes to lie in a sort of flap which wilts and remains soft, and 

 the crushing of the egg by the growth of firm tissue there is prevented. 



Fig. 132. — Egg puncture and feeding 

 puncture of Plum Curculio in young 

 plums. (From U. S. D. A. Farm. Bull. 



90S.) 



