LIFE HISTORY OF THE CODLING MOTH IN MAINE. 3 



SEASONAL-HISTORY STUDIES OF 1913. 



The codling-moth life-history investigations were conducted under 

 outdoor conditions, so that the results obtained would represent, as 

 nearly as possible, the normal life of this insect in the field. Accord- 

 ingly the rearing work was carried on in an open shelter erected for 

 this purpose. 



As a basis of comparison the laboratory methods were checked 

 with field observations chiefly by means of banded trees. The apple 

 trees were prepared for banding by removing the loose bark from the 

 trunk and main limbs. A burlap band of three thicknesses and about 

 5 inches in width was then placed tightly around the trunk about 

 3 feet above the base and held in place by an 8-penny wire nail. The 

 larvae were collected from these banded trees every three days. These 

 larva? hatched and fed under natural conditions, and hence their time 

 of leaving the fruit and their subsequent life history should correspond 

 with those of the larvae reared by the laboratory methods. 



The general method for carrying out the life-history studies is 

 illustrated in Plate II, figure 1. The cages used were large glass bat- 

 tery jars covered with cheesecloth tops, which were held in place by 

 rubber bands. In cage a (PL II, fig. 1) are shown the racks in which 

 the codling-moth larvae have spun their cocoons. The details of these 

 racks are illustrated in Plate II, figure 2, and described on page 4, 

 Pupation is recorded daily and after the moths emerge the length of the 

 pupal stage is computed. The moths are transferred daily from cages, 

 similar to cage a (PL II, fig. 1), and confined within cages like 

 cage b (PL II, fig. 1). The bottom of cage I is covered with 3 

 inches of moist sand and contains fresh apple foliage and a sponge 

 moistened with a sugar solution. The moths deposit their eggs upon 

 the foliage, which is removed each day and the number of eggs 

 recorded. The following data are obtained from cage b: (1) Days 

 before egg deposition; (2) time of egg deposition; (3) length of ovi- 

 posit ion period; (4) total number of eggs; (5) average number of 

 eggs ]><-:■ female; (6) length of life of male and female moths. 



hi order to prevent curling, the leaves are placed between two 

 pieces of wire screen until the leaves dry — cage c (PL II, fig. 1). 

 They are then removed from cage c to cage d (PI. II, fig. 1), in 

 which cage (lie embryological changes and incubation periods are 

 noted. Upon hatching (lie larva; are transferred to cage e (PL II, 

 fig. 1 ). This cage contains apples placed within a wire container and 

 ..! o the racks in which the larva; spin their cocoons. 



Since the tune of entering the fruit is known and since the time of 



leaving is found by a daily examination of the cocoon racks, tho 

 length of the feeding period is thus established. By following tho 



