330 OHIO EXPERIMENT STATION: BULLETIN 332 



When full grown the caterpillar is about 214 inches in length. 

 Usually it is almost white with a pinkish tint. The head is dark- 

 brown and brownish tubercles are found scattered over the body- 

 segments. 



The pupa is about li/^ inches in length, brownish in color and 

 bears a considerable number of strong-toothed processes. 



Life history and habits. — The eggs are deposited in June or 

 early July in crevices or abrasions in the bark of the host, and the 

 larvae upon hatching bore into the wood. Unlike many other borers 

 the greater part of the larva's activities are expended upon the 

 heartwood of the host and it is because of this injury to the valuable 

 part of the tree that the loss by this species amounts to what it does. 



It is generally supposed that 3 years are required to complete 

 the life cycle of this pest. 



Nature of work. — The boring by the larva causes the formation 

 of unsightly deformities on the host and occasionally the tree is 

 broken during high winds at the point of injury; but these are 

 insignificant when compared with the losses in the lowered quality 

 of the lumber and other products which the activities of this pest 

 bring about. 



The set posts in almost any fence row, particularly in the south- 

 ern part of the State, bear evidences of the work of this insect. 

 Posts so tunnelled not only rot more quickly than do sound posts, 

 but are more easily broken over. 



Food plants. — Black locust is injured to a greater extent than 

 any other species in Ohio. It sometimes harms other trees as well 

 and has been reported upon the following hosts: ash, maples, Cot- 

 tonwood, willow, chestnut and oak. 



Distribution. — This insect occurs throughout Ohio and is found 

 throughout the greater part of the United States, particularly east 

 of the Rocky Mountains. 



Natural enemies. — Since the eggs are large and conspicuous it 

 is possible that birds are of considerable economic value in picking 

 them up and destroying them before they have time to hatch. 



Control. — Since the adults choose abrasions and other rough- 

 ened areas on the trees, the careful smoothing up of such areas 

 before June might be of some benefit. This treatment may be 

 supplemented by the destruction of the boring larvae by injecting 

 carbon bisulphide in the tunnels. The foregoing suggestions apply 

 of course only to prized shade or ornamental trees. 



