60 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 



Cottonwood Leaf Beetle, Chrysomela scripta F. — The foliage 

 of cottonwood and willow is often skeletonized by the dirty yellow 

 larvae of this species. The overwintering form, a beetle about 

 one-fourth inch long, has a black head and thorax and yellowish 

 wing covers. In spring, it emerges from the debris about a tree. 

 The female deposits masses of yellow eggs on the under sides of 

 leaves. The larva eats the tissue of leaves, all but the veins, com- 

 pletes development in 2 weeks or so, and, attached to a leaf, pu- 

 pates with its head hanging downward. This insect probably 

 has two broods a year. 



Control Measure 1 or 2 (end of circular). 



Poplar Tent Maker, Ichthyura inclusa Hbn. — Silken tents 

 enclosing a branch or twig of a poplar are signs of colonies of the 

 black-mottled caterpillars that are the larvae of this insect. As 

 the caterpillars grow, they take more and more leaves into the 

 tent. The insect overwinters in the pupal stage. The female moth 

 that emerges from an overwintering pupa deposits masses of 

 eggs on leaves to produce caterpillars that feed in June. A second 

 brood of caterpillars occurs in August. 



Control Measure 1 or 2 (end of circular) applied when cater- 

 pillars are small. Infested branches should be cut out and burned. 



Oystershell Scale, fig. 5. — This is a common and destructive 

 pest of cottonwood. See under Ash. Control Measure 5 (end of 

 circular) in late winter or Control Measure 3 about the first of 

 June, after eggs hatch. Thorough spray coverage is essential. 



PRIVET 



Privet Thrips, Dendrothrips ornatus (Jablon.). — This thrips 

 in both adult and nymphal forms is a small, flat, elongate insect 

 that feeds in great numbers on privet foliage, withdrawing the 

 juices and chlorophyll. The adult thrips, dark brown and yellow, 

 have wings. The nymph, almost colorless at first, becomes lemon 

 yellow as it increases in size. Privet leaves affected by this insect 

 become dotted and dirty with excrement and they fall prema- 

 turely. Because this insect feeds at first on the under sides of 

 leaves, it often goes unnoticed until the leaves have been severely 

 damaged. 



Control Measure 3 or 8 (end of circular) applied in June, or 

 when the thrips infestation occurs. DDT should not be used on 

 privet, as it may cause serious leaf drop. 



