THE INSECTS AFFECTING THE BLACK LOCUST 

 AND HARDY CATALPA. 



THE INSECTi AFFECTING THE BLACK LOCUST. 



INTRODUCTION. 



The black locust {Robinice pseudacacia) is known under a number 

 of common names, the more prominent of which are "yellow locust" and 

 "black locust." In some sections these two names are supposed to refer 

 to two distinct species, but this is not the case. The term "black locust" 

 has been adopted by the United States Bureau of Forestry as the proper 

 common name for this species. By some it is also confused with the 

 honey locust (Gleditsia tridcanthos) from which it differs by having a 

 more upright growth, smaller, seed pods, and being devoid of the large 

 branched thorns so conspicuous on the latter. These thorns sometimes 

 entirely cover the trunk and lower branches. Unfortunately some sci- 

 entists have also fallen into this error, hence we find entomological writers 

 using the common names of trees in such manner as to make it impossi- 

 ble to determine to which species they refer. 



The natural geographical range of the black locust is from Pennsyl- 

 vania to Georgia, Iowa and Indian Territory, but through planting it has 

 become thoroughly naturalized in the Eastern and' Middle States and 

 Eastern Canada. The fact that this tree possesses a high degree of nat- 

 ural adaptability to widely different soil conditions, extreme hardiness, 

 vigorous growth, wonderful reproductive powers and great durability of 

 its wood, makes it one of the best of the post and pole timbers that can 

 be grown commercially under Ohio conditions. 



There is in the state a large area of land that is too poor and rough 

 for profitable agricultural operations, which will, if simply left alone, 

 grow black locust trees of- merchantable size in from ten to fifteen years. 



In spite of its many good qualities the black locust is not planted 

 extensively, because it is subject to attack by several serious insect ene- 

 mies. In some sections these pests are so numerous, and their work so 

 thorough and persistent, as to render it impossible to grow this tree. The 

 trunk and branches are sometimes injured by boring larvae to such an 

 extent as to cause death, or so weakened that they are readily broken off 

 by the wind. The leaves are eaten by a large number of insects, but 

 serious damage is confined to a few species. The buds are often injured 

 by a species of curculio. Serious damage from this source is compara- 

 tively rare, but the writer has observed cases where so many of the buds 

 were destroyed by these curculios as to' practically prevent the production 

 of seed. 



