INSECT PESTS OF OHIO SHADE AND FOREST TREES 317 



and sapwood both are attacked. Not only is the timber from in- 

 fested trees seriously mutilated and weakened, but wood-invading 

 fungi and bacteria are invited by the incisions in the bark of the 

 growing trees and the burrows left by the insect in posts and poles, 

 promote decay. 



Some trees are killed outright, while others, weakened by the 

 insect, may be broken over or limbs may be blown off in storms. 



When all phases of its work are considered, this is the most 

 severe insect depredator of the black or yellow locust in Ohio. 



Food plant. The yellow or black locust (Robinia Pseudacacia) 

 is the recorded host for the larva and the adult feeds upon the 

 flowers of goldenrod. 



Distribution. The locust borer is found throughout the greater 

 portion of the United States east of Colorado and has been reported 

 from Canada. 



Natural enemy. -The wheel bug (Prionidus cristatus) has 

 been recorded as destroying the adult beetles of the locust borer. 



Control. Successful and practicable measures for the control 

 of this insect have never been found. Prized trees may be protected 

 for a time, until they become too large, by opening up the burrows 

 of the boring larvae, introducing therein a small lump of potassium 

 ferrocyanide, and closing the opening with putty or grafting wax. 

 Eepellent washes applied to the trunk during the egg-laying season 

 have proven both expensive and only moderately successful. The 

 destruction of goldenrod in the vicinity of locust groves is thought 

 by some to possess merit, since the process removes the source of 

 attraction for the adult beetles. For the protection of large plant- 

 ings or the wild growth of woodlands, an effective control measure 

 is yet to be found. 



THE LOCUST TWIG BORER 

 (Ecdytolopha insiticiana Zell.) 



Description. In its injurious stage this insect is a whitish or 

 pale yellowish larva about one-half of an inch long. The adult is a 

 moth with a wing expanse of about three-fourths of an inch. The 

 fore wings are dark ashy-brown with a dull pinkish-white patch on 

 the outer part. Within this patch are several small black spots. 

 The hind wings are lighter. 



Nature of work. The locust twig borer is found within swell- 

 ings borne by the smaller twigs of black or yellow locust. These 

 swellings measure from 1 to 3 inches in length, a characteristic 

 specimen being illustrated in Plate LXIV, Fig. 1. White sawdust- 

 like castings are discharged from a hole in the larger part of the 



