34 



MASS. EXPERIMENT STATION BULLETIN 226. 



a condition of ;iffairs led the Station to engage in a study of the insect, 

 vvitli particular reference to determining the proper timing of the "cover" 

 sprays following the calyx spray. 



It was at first supposed that this "side worm" injury was due almost al- 

 together, if not entirely, to second brood larvae. Consequently attention 

 was at first directed toward determining the approximate date when this 

 brood appeared, and also its relative size and importance. As the project 

 developed, it became evident that a more accurate knowledge of the entire 

 life history of the insect was necessary, if a satisfactory solution of the 

 problem was to be reached. Beginning with 1923, therefore, the complete 

 seasonal history of the insect has been followed. Some of the more im- 

 portant events in the life history of the insect, as recorded for the three 

 seasons, are summarized in the following table: — 



Table 1. Development of the Coddling Moth, as recorded in 1923, '24. and '2-5. 



1923 

 Beginning of spring pupation I'Uiy 3 



Date of last pupation June 26 



Duration of pupa stage 8-24 days 



Emergence of first moths May 27 



First period of maximum emergence Tune 2-4 



Second period of maximum emergence Juno 20-24 

 Date of last emergence July 2 



Duration of egg stage 5-10 days 



Emergence of second brood moths -July 20-Aug. 29 



Period of greater emergence Aug, 3-6 



Appearance of second brood larvae A.ug. l-.Sept. 6 



Comparison of the dates of the developivient 

 Table 1, with the seasonal development of the ; 

 period is noted below: — 



1924 

 May 3 

 .July 11 

 12-2 3 days 

 May 24 

 May 26-30 

 -June 22 27 

 July 24 

 4-12 days 

 July 21-Sept. 

 (^ug. 4-9 



1925 

 April 24 

 June 20 

 8-24 days 

 May 12 

 May 16-18 

 Juno 3-9 

 July 3 

 4-11 days 

 ■July 11- Aug. 28 

 .July 31- Aug. 12 



A.ug. 2-Sept. 17 July 24-Sept. 12 



of the insect, as shown in 



ijiple during the three-year 



Table 2. Comparison of the .seasonal development of the nj)ple with that of 



the codling moth. 



Apple Develop.^ient 

 Blossom buds showing pink 

 Pre-pink spray 



Codling Moth Develop.'ment 

 Beginning of pupation 



Calyx spray 



Moths appearing (1-6 days before 



calyx spray) 

 First period of maximum ajijiearance 



of moth 

 Second period of maximum 



emergence of moth 



3-4 weeks later 

 (2-3 weeks in 192.5) 



In general tlie weatJier conditions prevailing during 1923 and "1924 were 

 \ery similar, particularly as regards the frequently recurring periods of 

 cold and unfavorable weather in May. These retarded the normal advance 

 of the season and caused a corresponding slowing up of de\elopiuent on the 

 part of the codling moth. In 1925 insect activities commenced fully a 

 week to ten days earlier than in the two previous years, and held this ad- 

 vantage throughout most of the season. This difference is reflected in 

 Table 1 above, where it will be noted that the dates of various steps in 

 seasonal development of tlie insect for 1923 and 1924 were nearly the same, 

 while in 1925 they were about ten days earlier. It naturally followed that 

 first brood lar\ae began to mature and lea\e the fruit that much earlier 

 than usual, so that a larger proportion formed pupae and emerged as 

 second brood moths. 



