THE BLACK LOCUST TREE 217 



species, but they had fruited for many years, and some of them had 

 reached a foot or more in diameter at the base. They had grown so 

 thriftily that their continued growth was naturally expected by those 

 who had planted them ; but when the borers came the trees were every- 

 where injured or destroyed as by a pestilence. Within a very few years 

 after the first appearance of those insects in that western region noth- 

 ing remained of the almost numberless groves and rows of those trees 

 except their blasted remnants and the young shoots that the vigorous 

 and unconquered roots were striving to bring forth. That condition 

 remains there to this day, essentially unchanged except that even the 

 stumps and roots of the blasted trees have, from time to time, been 

 removed to reclaim for other uses the soil which they formerly oc- 

 cupied. Because of that wide destruction one may now go many 

 miles in that great region without seeing more than a few neglected out- 

 casts of that once popular tree; just enough to afford breeding places 

 for a few of the hardy and prolific borers, which are always ready to 

 commit their ravages. I was an eye-witness of that great destruction 

 from its beginning to its consummation, and afterward had unusual 

 opportunity to observe its effects when investigating the subject of 

 foresting the prairie soils of Iowa. Similar destruction also occurred 

 as the borers traversed the country between their native region and the 

 Mississippi valley, the effects of which still remain there. 



The question now arises whether there is any known remedy for 

 the attacks of those insects. Unfortunately no effective remedy of 

 general applicability has yet been discovered. The attacks of the in- 

 sects are not upon any of the parts concerned in reproduction, such 

 as might interfere with the propagation of the tree, but upon its grow- 

 ing substance, which is constantly exposed at all seasons of insect ac- 

 tivity. Therefore its inflorescence and fruitage need no protection, and 

 proposed remedies must be applied to the surfaces of the tree and 

 directed against some important function in the life of the insect, 

 mainly that of reproduction. The killing of the insects in any con- 

 siderable numbers seems to be quite impracticable. The few remedies 

 which have been proposed are fluid applications which are harmless to 

 the trees and so repugnant to the insects that they will not puncture 

 any surface to deposit their eggs which has been so covered. But 

 many difficulties attend the application of such remedies. The leaves 

 and terminal portion of the twigs are doubtless too delicate for such 

 treatment, .but the bark is not easily injured by it. The application 

 with a brush to the bark of the trunk and branches of lime whitewash 

 mixed with a solution of whale-oil soap has seemed to prevent the 

 female of the borer in the beetle stage from puncturing the bark to de- 

 posit her eggs. But to be effective all such applications must carefully 

 be made to the entire surface of the trunk and to that of the branches 

 which have reached a couple of inches or more in diameter. They must 



