SHADE TREE INSECTS 



(4) Species definitely unfavorable in early larval stages but highly favored by larger caterpillars — 



pine (all species) beech 



hemlock spruce 



southern white cedar (all eastern species) 



(5) Species not favored in any larval stage — 



ash butternut American holly 



locust red cedar balsam 



tulip tree black walnut sycamore 



dogwood 

 Stands composed entirely of species in class 1 may be completely defoliated. Stands of species 

 in class 2 may also be infested, but the likelihood of complete defoliation is distinctly less than in 

 pure stands of class 1 trees. Stands restricted to the species in class 3 are at times lightly infested, 

 but cases of heavy defoliation are extremely rare. Infestation cannot originate in stands composed 

 entirely of species in class 4, and stands restricted to the species in class 5 are practically immune. 



Mixtures of classes 1 and 2 are highly susceptible to heavy defoliation. Mixtures of 1 and 3 

 are highly susceptible only when the proportion of foliage in class 1 is high enough to allow a large 

 number of larvae to enter the later stage of development in a vigorous condition. In such mixtures 

 trees in class 1 are usually entirely defoliated before those in class 3 are severely attacked. In 

 mixtures of classes 1 and 4 the defoliation of the latter is also dependent upon the proportion of 

 class 1 trees present. If sufficient class 1 foliage is available for the larvae to reach the third stage 

 of development in a healthy condition, trees in class 4 may be severely attacked. Mixtures of 

 classes 2, 3, 4, and 5 are seldom defoliated, although the likelihood is greater than in mixtures of 

 3, 4, and 5. 



Gypsy Moth 



Egg Masses 



and 



Empty Cocoons 



on the 



Trunk of a Tree. 



