406 ANN['AL REPORT OF THE Off. Doc. 



mixed bark and excremenl projecting from the openings of the 

 cavities. In the spring the eaterpilhus leave these cavities and pass 

 to the leaf buds which thej bore into, following along in the stem 

 bearing the bud, eating its substance and causing the leaves to wilt 

 and die. At this time their presence may be discovered by looking 

 for the wilted tufts of leaves which are very noticeable among the 

 others not thus allected. After boring out one shoot the caterpillar 

 passes to another which it destroys in the same way, and it may at- 

 tack several before becoming full grown. When the caterpillar has 

 reached full size, it forms a small w^eb either in withered leaves on 

 the tree, in leaves or rubbish around the tree, or it may lie exposed 

 on the bark. In either case it now remains quiet for a week or ten 

 days, at the end of which time the internal changes necessary having 

 been completed, the adult moth appears and lays eggs for a new 

 brood. The caterpillars which hatch from these eggs attack new 

 growth of the tree, entering the young twigs where these give off 

 leaves, or sometimes entering the stems of the young fruit, and later, 

 in some cases, boring into the fruit itself. This history is probably 

 repeated by the next brood, and in the fall the eggs for the third 

 brood are probably laid on the bark and the little caterpillars burrow 

 into the bark to pass the winter. There are therefore three broods 

 each year. 



Injuries. 



The spring brood which passes the winter in cavities in the bark 

 at the crotches, is the one which is most noticeably injurious. As it 

 hores into shoot after shoot in the spring, the number of these which 

 are killed when the insect is abundant is very great, often several 

 hundred of the young shoots on a single tree being destroyed. The 

 result of this upon the tree is to make it scraggy and irregular and 

 to cause it to expend its energy in the formation of new growth at 

 a time when this energy should be devoted to the production of fruit. 



Treatment. 



The best method of control for this insect which has as jat been 

 found, is to spray the trees in winter to destroy the caterjiillars which 

 are then in cavities in the bark at the crotches. 



To successfully carry out this method it is advisable to lightly 

 scrape the larger crotches with some blunt edged instrument — a 

 hoe has been found to be well adapted to this purpose. After scrap- 

 ing in this way the tree should be sprayed with kerosene emulsion, 

 made and applied as follows: 



Kerosene, 2 gallons. 



Whale-oil soap, ^ pound. 



Water, 1 gallon. 



