62 



MASS. EXPERIMENT STATION BULLETIN 233 



Date of Maturing 

 During August, 

 During September, 

 During October, 



Time spent in Fruit 

 20—22 days 

 28—30 days 

 35—40 days 



These larvae are maturing and leaving tlie fruit in largest numbers from 

 the first of September to early October. After emerging, the larvae at once 

 form their closely woven winter cocoons in any convenient place offering 

 concealment and protection. Witliin these cocoons, they pass through tlie 

 winter, transforming to moths the following spring. In Massachusetts, tlie 

 insect has shown no tendency toward any pupation in the fall or toward a 

 third brood of moths. 



Overlapping of Broods. . 



A study of the seasonal history of the codling moth shows that in a 

 typical season there is an overlap of three to five days between the last 

 emerging spring moths and the first of the summer brood. By the time tlie 

 last of the spring moths had died, the greater part of the summer brood had 

 emerged. It is evident, therefore, that moths may be present in an orchard 

 continuously from late May until the middle of September. 



The different life stages are so prolonged that the first larvae to hatch 

 in the spring pupate before egg deposition is finished. Larvae are hatch- 

 ing for three weeks or more after pupation has begun. There was found 

 to be a gap of seldom more than two or three days between the time egg 

 laying by the spring moths had ceased and the first eggs of the summer 

 moths are laid, and sometimes they overlap. 



It is evident, therefore, that every year some stages, at least, of the two 

 broods overlap, and consequently there are few days during the season, 

 after the fruit has set until harvest, when it is not subject to infestation. 



Below is shown a comparison of some of the more important stages in 

 the development of the insect with the seasonal development of the apple, 

 for the three-year period studied: 



Apple Development 



Blossom buds showing pink 



1 — 6 days before "calyx" spray 



"Calyx" spray 



S — 4 weeks later (2 — 3 weeks in 1925) 



Insect Developmeut 



Beginning of pupation 



1st moths appearing 



1st period of maximum appearance of moths 



2d period of maximum appearance of moths 



Some of the more important events in the seasonal history of the codling 

 moth, from the three seasons' study in Massachusetts, are summarized in 

 the following table: 



Beginning of pupation 

 Date of last pupation 



1923 

 May 3 

 June 26 



1924 

 May 3 

 July 11 



1925 

 April 24 

 June 20 



Duration of pupa stage 8-24 days 12-23 days 8-24 days 



Emergence of 1st moths May 27 May 24 May 12 



1st period of maximum emergenceJune 2-^ ^Fay 26-30 May 16-18 



2d period of maximum emergenceJune 20-22 June 22-27 June 3-9 



Dat« of last emergence July 2 July 24 July 3 



Duration of egg stage 5-10 days 



Appearance of 1st brood larvae June 7 



tBmergence of 2d brood moths 

 Period of greatest emergence 

 Appearance of 2d brood larvae 



4—12 days 

 June 13 



4—11 days 

 May 29 



July 20-Aug. 20 July 21-Sept. 3 July 11-Aug. 28 

 Aug. 3-6 Aug. 4-9 July 31-Aug. 12 



Aug. 1-Sept. 6 Aug. 2-Sept. 17 Julv 24-Sept. 12 



