22 SHADE TREE GUIDE. 



Biters. These commonly attack the foliage and may work as 

 adults (beetles) or as larvae (caterpillars or worms). Control is 

 determined by a knowledge of the life history of each species, but a 

 general remedy is to poison their food. The best means is to 

 spray thoroly with arsenate of lead according to directions given on 

 the commercial packages. Banding a tree trunk with cotton or 

 some sticky stuff is useful only when the insects are crawling up. 

 Bag worms, tent caterpillars, etc., which form conspicuous shelters 

 or colonies in tree crowns, and forms like tussock moths which set 

 egg masses on nearby structures, as well as on the trees, can often 

 be destroyed by hand or by fire even more successfully than by 

 spraying. 



Suckers. These appear as minute, crawling insects, frequently 

 protected by woolly, waxy or scaly coverings. They locate on the 

 younger branches, or on the leaves, often in enormous numbers, and 

 live by sucking the sap. Some forms can be washed away with a 

 strong jet of water from a hose, but in most severe cases thoro and 

 repeated spraying with a caustic, or with a penetrating oil, is neces- 

 sary. Fish-oil soap suds is good for the tenderer forms, especially 

 when reinforced with tobacco extract; lime-sulfur or soluble oil is 

 best for those with scaly armor. 



Borers. Boring insects work, as beetles or worms, in the twigs 

 or buds, in heartwood, or, most frequently, in the cambium layer 

 between sapwood and bark. Their presence is indicated by broken 

 branches and by small holes in the bark beneath which wood dust 

 is often found. In our territory a few species attack healthy trees, but 

 most seek out those whose vitality has been lowered. Control is dif- 

 ficult because the pest is mostly out of sight, and, tho help can some- 

 times be given, it usually is necessary to depend chiefly upon keep- 

 ing the trees in good health. Against the locust borer anything else 

 is useless. Any hickory tree that is seriously infested with the hick- 

 ory borer is doomed and should be cut down and burned without de- 

 lay for the sake of nearby trees, and the latter should be stimulated 

 by feeding to ward off attack. Leopard-moth larvae are especially 

 fond of young, newly-planted street trees which are struggling to 

 establish themselves. A measure of control is possible by cutting 

 out the boring worms, by crushing them with a wire run into the 

 burrows, by injecting carbon bisulfid, and especially by encouraging 

 insect eating birds. More specific advice is given in a publication 

 of the State Agricultural Experiment Station, New Brunswick, "In- 

 sect Enemies of Ornamental Trees and Shrubs," by Harry B. Weiss, 

 which will be sent upon request. 



