34 MASS. EXPERIMENT STATION BULLETIN 226. 



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

 with 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. 



Beginning of spring pupation 

 Date of last pupation 

 Duration of pupa stage 

 Emergence of first moths 

 First period of maximum emergence 

 Second period of maximum emergence 

 Date of last emergence 

 ' Duration of egg stage 



Emergence of second brood moths -July 20-Aug. 29 July 21-Sept. 2 July 11-Aug. 28 



Period of greater emergence Aug. 3-6 Aug. 4-9 July 31-Aug. 12 



Appearance of second brood larvae Aug. 1-Sept. 6 Aag. 2-Sept. 17 July 24-Sept. 12 



Comparison of the dates of the development of the insect, as shown in 

 Table 1, with tiie seasonal development of the apple during the three-year 

 period is noted below: — 



Table 2. Comparison of the seasonal development of the apple with that of 



the codling moth. 



Apple Developmext Codling Moth Developmext 



Blossom buds showing pink Beginning of pupation 



Pre-pink spray 



Moths appearing (1-6 days before 



calyx spray) 

 Calyx spray First period of maximum appearance 



of mo til 

 3-4 weeks later Second period of maximum 



(2-3 weeks in 192-5) emergence of moth 



In general the weather 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 development on the 

 part of the codling moth. In 192.5 insect activities conmienced 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 the insect for 1923 and 1924 were nearly the same, 

 while in 192.5 they were about ten days earlier. It naturally followed that 

 first brood larvae began to mature and leave the fruit that much earlier 

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

 .«<econd brood moths. 



