INSECT PESTS OF OHIO SHADE AND FOREST TREES 243 



shade trees, the presence of great numbers of the obnoxious crawl- 

 ing caterpillars is so repulsive as to be quite intolerable to many 

 persons. 



Food plants. According to Dr. E. P. Felt, the following is the 

 list of food plants of this species : "Linden, maples, locust, peach, 

 plum, cherry, rose, strawberry, apple, sweet gum (Liquidambar 

 styraciflua) , dogwood, "black gum," sour gum (Nyssa sylvatica) , 

 ash, elm, black walnut, hickory, walnut, oak, black oak, post oak, 

 white birch, gray birch, willow and poplar." Of the list, sugar 

 maple and oak are the favored hosts, the former suffering tre- 

 menduous injury in some of the northeastern states. 



The foregoing list suggests that the insect is a very general 

 feeder; and because of this wide range of hosts its wide distri- 

 bution, as will be shown in the following paragraph, is partly 

 accounted for. 



Distribution. A survey of the literature pertaining to this 

 insect reveals the fact that it has been reported one time or another 

 over nearly every section of the United States; hence Ohio will 

 likely be invaded at some time by an outbreak, particularly since 

 severe scourges have occurred in both New York and southern 

 Illinois. 



Natural enemies. A large list of the caterpillar-destroying 

 birds prey upon the larvae of this species, while to a certain extent 

 the eggs and moths are destroyed by the same agency. 



Parasitic Hymenoptera of several species are recorded from 

 the larvae and pupae of this species as are also several Dipterons. Of 

 the former, Pimpla conquisitor is mentioned prominently, and of 

 the latter, Tachina mella is sometimes abundant. 



Of the predaceous beetles, Calosoma scrutator Fabr. and C. 

 wilcoxi Le. C. are valuable. 



Since the forest tent-caterpillar is a native insect, doubtless we 

 should give much credit for the early disappearance of severe out- 

 breaks of it to the natural control agencies. 



Control. Several writers in dealing with this insect place con- 

 siderable dependence in the plan of collecting the egg masses during 

 the winter. There is some value in this suggestion since most of 

 the egg clusters are found on the lower branches, but in the writer's 

 experience the collecting of egg clusters is rarely satisfactory due to 

 the fact that invariably some are missed and ordinarily the labor in- 

 volved in the process is so expensive that the method is unprofitable 

 as compared with others which at the same time are more efficient. 

 If egg collecting is depended upon, however, the work should all be 

 finished before the buds break in the spring. 



