12 BULLETIN 435, TJ. S. DEPARTMENT OF AGEICULTUEE. 



In Virginia young apple trees which do not receive the arsenical 

 spray are frequently defohated by the apple leaf-sewer, whereas 

 neighboring orchards in bearing, having received one or more 

 codling-moth spray apphcations, ahnost entirely escape. Young 

 orchards should receive the arsenical spray as soon as this pest 

 appears in numbers sufficient to cause any serious damage. 



Mr. Fred Johnson ^describes conditions in Niagara County, N. Y., 

 in 1905, as follows: 



The depredation of this pest is becoming quite marked in many orchards in the 

 Youngstown district and also in orchards on the Canadian side of the Niagara River. 

 The worst infestation coming under my notice is in an orchard of about 60 acres of the 

 Greening, Baldwin, and Duchess of Oldenburg varieties. 



On many of these trees nearly all the leaves are sewn together and have a scorched 

 appearance. The larva does not appear to attain its full growth in one leaf, but as 

 soon as it has eaten the gi'eater part of the tissue on the inside of the leaf which it has 

 sewn together it gnaws a hole through the side of the leaf and escapes. It then attacks 

 another leaf and proceeds as with the one it has vacated. 



This entire orchard is in sod and received only an indifferent spraying early in June. 

 Parts of trees and whole trees that were fairly well sprayed have good foliage, whereas 

 the foliage of trees or parts of trees which received little or no spray has either fallen 

 or presents a scorched appearance on the tree. 



Duchess of Oldenburg trees sprayed June 9 and June 23 with 4 pounds of arsenate 

 of lead to 50 gallons of full-strength Bordeaux mixture are quite free from this post, 

 whereas its ravages on the check trees are very marked. The condition of the foliage 

 in this orchard at this date indicates that the pest can be held in check by thorough 

 spraying at the dates that applications are usually made for scab and codling moth. 



Mr. Johnson used 4 pounds of arsenate of lead to 50 gallons of water, 



but the spraying experiments conducted at Winchester, Va., indicate 



that 2 pounds of arsenate of lead to 50 gallons of water is sufficient for 



the control of the apple leaf-sewer. Lime-sulphur solutions or 



Bordeaux mixture may or may not be added, according to orchard 



conditions. 



SUMMARY. 



When present in sufficient numbers, the apple leaf-sewer may 

 •cause serious injury to apple foliage. 



The apple leaf-sewer is generally distributed over the North and 

 Central Atlantic States, the Middle West, and in portions of Canada. 



The insect appears to confine its attack to the apple. 



The newly-hatched larva spends the first 3 or 4 weeks of its life 

 under a silken covering on the underside of the leaf. The remainder 

 of the larval feeding period is passed within a succession of folded 

 leaves. It destroys these leaves by eating the upper parenchyma. 



In appearance the egg is very similar to that of the codling moth. 

 The average period of incubation was found to be 8.8 days. 



The full-grown larva is yellowish green, with an orange-colored 

 head and thoracic shield, the latter with irregular black markings 



> Unpublished notes, Bureau of Entomology. 



