SHADE TREE INSECTS 



39 



The cocoon on the surface of the ground is of loosely woven silk and into it 

 particles of earth and rubbish are glued so that it closely resembles its surround- 

 ings. 



Life History. The moths appear about the iast of June or early in July. The 

 females soon deposit their eggs in groups of about 50 to 100 on the under side of 

 the leaves. Upon hatching in early August, the young caterpillars feed on the 

 under side of the leaves and skeletonize them. Later they eat the entire leaf 

 except the large veins and may also attack the tender bark on new shoots. Entire 

 branches and sometimes whole trees may be defoliated. The caterpillars feed 

 in groups especially when young, but maintain this habit to a certain extent 

 throughout their life. When not feeding they may be found clustered on the 

 trunk or branches with the rear part of the body slightly elevated. They reach 

 maturity- in late August and September, at which time they descend to the 

 ground and construct a loose silken cocoon under rubbish or among loose particles 

 of earth. They usually overwinter as caterpillars in this cocoon, transform to 

 pupae the following spring, and later emerge as moths. There is only one genera- 

 tion a year in most of northern United States and Canada but farther south there 

 are two. 



Egg mass on surface of leaf. 

 Mature caterpillar. IJ^X. 



Red-Humped Caterpillar. 



Greatly enlarged. Courtesy. N. H. Agr. Expt. Station. 

 Courtesy, Conn. .\gr. Expt. Station. 



Control. The insect can be controlled by a thorough application of lead arsenate 

 mixed in the proportion of 4 pounds to 100 gallons of water with 2 pounds of 

 flour or 1 pound of calcium caseinate added as a sticker. It should be applied when 

 the young caterpillars first begin to appear in early August. 



In the case of a light infestation on small trees, the colonies of caterpillars may 

 be collected by hand and destroyed when they are young and are clustered on 

 the foliage of a single branch or twig. 



Essig, E. O.. and Hoskins, W. M. Calif. .\gr. Ext. Serv. Circ. 87:75. 1934. 

 Houser, J. S. Ohio Agr. Exp. Sta. Bui. 332:254-256. 1918. 

 Lounsbury, C. P. Hatch Exp. Sta. Mass. Agr. Col. Bui. 28:17-19. 1895. 

 McDaniel, E. I. Mich. Agr. Exp. Sta. Spec. Bui. 243:23-24. 1933. 

 Sanderson. E. D. N. H. Agr. Exp. Sta. Bui. 139:216-218. 1908. 



