REPORT OF THE STATE ENTOMOLOGIST I9I3 63 



number of insects, which are not readily explainable. The mere 

 fact that this planting was in a section where the locust borer was 

 generally abundant and injurious should have served as a warning 

 regarding the possible outcome of such an undertaking. 



This latter case is undoubtedly an extreme one, and yet it is 

 one of the probabilities which must be faced by those contemplating 

 extensive plantings of this valuable tree. 



The parent of the locust borer, as most people realize, is a 

 rather slender, black beetle less than three-quarters of an inch long 

 and very prettily marked with golden yellow. It may be found in 

 considerable numbers feeding on goldenrod blossoms. The females 

 deposit their oval, whitish eggs here and there in crevices of the 

 bark and the young grubs spend the winter in the outer part of 

 the living inner bark. The larger grubs, as is well known, when 

 abundant may riddle the inner portion of the trunk with galleries 

 about one-quarter of an inch in diameter and running mostly with 

 the grain of the wood. 



As suggested above, from our present state of knowledge, it ap- 

 pears unwise to plant the black locust in sections where this borer 

 is abundant and destructive. Plantings already established should 

 be carefully watched for early indications of injury, most easily 

 detected during the spring and early summer by bleeding and ejected 

 borings. Very badly infested trees or parts of trees should be cut 

 and destroyed before the first of August, in order to prevent the 

 insects maturing. It is perhaps unnecessary to add that the general 

 adoption of this plan would probably result in a very satisfactory 

 control of the borer. Doctor Hopkins states that the hibernating 

 larvae may be destroyed by spraying the trunks and branches with 

 a strong solution of kerosene emulsion. Ordinarily, in our opinion 

 it would be safer to make this application in the spring and not 

 later than the first of April. Pure kerosene, petroleum or petroleum 

 compounds may result in injury to the trees unless used with much 

 care. Experiments at Salamanca last July showed that the nearly 

 full-grown grubs could be killed or driven from their burrows by 

 applications of a creosote preparation which was said to be harm- 

 less to the trees. 



Some trees appear to be more resistant to attack than others, 

 and it has been suggested by Doctor Hopkins that work along this 

 Jine might be attempted in the case of the black locust and an 

 effort made to obtain borer-resistant trees, either by cross-breeding 

 or through propagation by cuttings. 



