THE APPLE LEAF-SEWER. 11 



NATURAL ENEMIES. 



The larvae of Ancylis nubeculana- are attacked by a number of 

 parasitic and predacious enemies. 



Pseudomphale ancylae Girault, n.sp. [MSSJ, a hymenopterous para- 

 site belonging to the family Chalcididae, was found to be a very 

 common enemy of larvae of the apple leaf-sewer in the vicinity of 

 Winchester, Va. Six hundred and seventy-eight infested leaves 

 were collected in the fall of 1914, and of these, 98 contained the pupal 

 cases of this parasite, indicating that about 15 per cent of the leaf- 

 sewer larvse were destroyed. In late summer and early fall the para- 

 sitic larvse leave the body of the host and spin their cocoons within 

 the folded leaf, attaching the cocoons along the midrib of the leaf. 

 From 4 to 6 parasites emerge from a single leaf-sewer larva. Only 

 in two instances on examination at this time were pupae found in 

 these cocoons, and it appears that the parasite does not commonly 

 overwinter within the folded leaf. 



No parasites were reared from the breeding material in the spring 

 of 1915. 



Riley reared a braconid, Rhysipolis phoxovteridis Riley MS., from 

 a leaf-sewer larva, in 1884, at Kirkwood, Mo., and in 1877, at Ithaca, 

 N. Y., reared Angitia paediscae Riley MS. 



Ants are an important factor in reducing the number of larvae and 

 pupae during the winter and spring. In the spring of 1915, during 

 the pupal period, ants almost ruined the writer's breeding material, 

 ■ which had been placed upon the ground under wire rearing cages. 



REMEDIAL MEASURES. 



The apple leaf-sewer larva migrates from one leaf to another 

 several times during the season, which renders the control of this 

 insect by the use of arsenical sprays very simple. According to the 

 life-history studies of this insect at Winchester, Va., in 1915, the 

 eggs begin to hatch about June 14 and continue hatching until about 

 July 2, the maximum number of larvae appearing about June 20. 

 The regulation arsenical spray of 2 pounds arsenate of lead to 50 gallons 

 of water , applied by June 15, will therefore control this insect, and as 

 the second spray for the first hrood of codling moth is usually applied 

 by the above date, in the vicinity of Winchester, no special application 

 will be required for the control of the apple leaf-sewer. 



Spraying experiments conducted at Winchester, Va., indicate that 

 even the full-grown larva is extremely sensitive to arsenical sprays 

 and readily killed by that means. This is easily understood when 

 one remembers that on sewing up the leaf the larva consumes all the 

 upper parenchyma and can not escape the arsenate of lead deposited 

 thereon by the spray. 



