44 MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTURE 



a small nest. Its work causes the foliage of cypress to turn brown 

 early in the spring. It is distributed through central and southern 

 California and often is found working with the cypress tip moth. 



BUD MOTHS 



Frequently the tips of branches on young and older trees appear 

 to be killed, but on close examination it is found that the twigs are 

 not injured and the damage is confined to the buds, developing 

 needles, or terminal leaves. These are webbed together to form a 

 case, within which a smooth, hairless, very active caterpillar is 

 found. Work of this character is done by a group of bud moths, 

 mostlv belonging to the family Tortricidae, which are true leaf eaters 

 and tlierefore belong to the group of defoliators (p. 78). Usually 

 their damage is confined to the leaves at the tips of branches, but 

 during epidemics the older needles on the branches are also fed upon, 

 and large forest areas may be completely defoliated and the trees 

 killed. This group of bud moths, while it includes hundreds of 

 species of only minor importance, also includes such conspicuous 

 forest-tree defoliators as the spruce budworm, hemlock budworm, and 

 lodge-pole pine needle tier. 



SAP-SUCKING INSECTS 



A large group of insects, such as bugs, aphids, and scales, belonging 

 to the orders Hemiptera and Homoptera, and the mites and red 

 spiders of the class Arachnida, which are closely related to insects, 

 are equipped with slender beaks which they insert into the tender 

 leaves or shoots of plants and feed by sucking the juices from these 

 succulent parts. These various insects and mites are more important 

 in the orchard and garden, or to shade trees, than they are in the 

 forest. A few species, hoAvever, do noteworthy damage to small 

 forest trees, and a few are important enemies of larger trees. Since, 

 on the whole, they are more apt to be found seriously affecting young 

 trees than older trees, they are considered at this time. 



On shade and ornamental trees they can be controlled through 

 the use of such contact sprays as lime-sulphur, miscible oils, or nico- 

 tine sulphate mixed with soap solution. Under forest conditions, 

 however, the use of such sprays seldom is practical, and so far no 

 control work of this kind has been undertaken in western forests. 



KEY TO DIAGNOSIS OF SAP-SUCKING INSECT INJURY 



A. Trees appearing sickly, leaves or stems not chewed but yellowing or 

 covered witli small incrustations, scales, powdery or cottony tufts, 

 or small, soft-bodied insects. Trees frequently dripping with sticky 

 exudation or covered with black smut. 



1. Trees dripping with sticky exudation, black smut usually 



abundant. Colonies of small, soft-bodied bugs, usually 

 with two cornicles or protuberances on rear of abdomen, 

 appearing on leaves or tender stems aphids, page 45. 



2. Leaves yellowing in spots, or bent. Small tufts of cottony 



wax appearing on under sides of leaves 



adelgids and scales, pages 47, 49. 



3. Small, circular, oval, or elongated shells or scales on leaves 



or twigs. Black smut not usually abundant scales, page 49. 



4. Leaves yellowing, covered with fine, nearly invisible webs or 



silvery coating , spider mites, page 51. 



