50 



MASS. EXPERIMENT STATION BULLETIN 353 



or in bark crevices. In about 10 days the beetles appear. They presently begin 

 feeding but cause no material damage at this time. With the approach of cold 

 weather, the beetles seek shelter and hibernation quarters. One generation a year 

 is usual in Massachusetts. The number of generations produced in a season, 

 however, varies in different localities and even in the same locality may be affected 

 by the earliness or lateness of the season. Two and three generations have been 

 reported from localities farther south on the Atlantic Coast, while in California 

 there mav be as manv as five. 



/ 



Elm Leaf Beetle 



1. A leaf skeletonized by the grubs. Actual size. 

 3. Pupae, bottom and top views. Enlarged. 



2. Grub. Enlarged. 



4. Adult beetle. Enlarged. 



Control. The usual recommendation is to spray the trees with lead arsenate 

 as soon as they reach full foliage. The spray should be directed to the under side 

 of the leaves where the larvae feed. During very severe infestations it would 

 be advisable to spray twice. The first application should be made when the 

 leaves are about three-quarters grown while the overwintered adults are still 

 feeding and laying their eggs. A second spray should be applied when the young 



