MASSACHUSETTS APPLE INDUSTRY. 35 



During the last three years it has been possible to follow the seasonal 

 development of the insect in the eastern part of the state, through the 

 assistance of Mr. A. N. Calkins of Harvard. Thus far there has been 

 found to be very slight difference between the two points, a matter of 

 two or three days in either direction being the most thus far noted. 



In a survey of the results to date, certain outstanding facts are sig- 

 nificant. There have been, each year, two widely separated and distinct 

 periods of abundance in the emergence of first brood moths. The first 

 coincides very closely with the time of the calyx application. By careful 

 spraying at this period, growers have been able to practically eliminate 

 "blossom end" injury, and cut down very largely the danger of a serious 

 second brood. 



In the last three seasons there has been a second great peak of abundance 

 which, from our records, may contain the greater part of the total emer- 

 gence. This second peak in 192.3 and 1924 occurred three or four weeks 

 after the first. In 192-5 the period was shortened by the extremelj' hot 

 weather early in June. The main damage caused by the codling moth 

 at the present time appears to be largely due to this irregularity in the 

 emergence of moths and consequent long-drawn-out appearance of first 

 brood larvae. This causes the early "side worm" injury which has been 

 so prevalent in late years. 



It is clear that any spray to be effective under such conditions mu.st be 

 timed so as to kill a maximum number of larvae before they enter the 

 apple, and emphasizes the need of the cover or post-calyx spray. This 

 needs to be applied very thoroughly since we have found that young 

 larvae, on their waj' to enter the fruit, will feed to some extent on the 

 foliage. In the years 1923 and 1924, this would have properly been ap- 

 plied about four weeks after the calyx spray. In 192.5, due to the speed- 

 ing up of development from the hot week in June, this spray would have 

 been timed about three weeks after the cahx spray. It is worthy of 

 note that those growers who sprayed during or just after that week re- 

 ported very clean fruit in those blocks treated. 



As our knowledge of the habits of this insect develops, more than one 

 spray during this period may be found advisable, to give continuous pro- 

 tection during the long period over which infestation of fruit may take 

 place. A survey of some orchards in the main fruit growing sections 

 of the state brought out the fact that growers who made two or more 

 applications of either spray or dust at two-weeks intervals after the calyx 

 application reported early "side worm" injury almost negligible. 



Growers have come to believe that the calyx and one or two cover 

 sprays after the calyx will so control the pest that the probability of a 

 serious second brood can be ignored. Ordinarily this may prove true. In 

 192.5, however, there developed a comparatively large second brood, 

 throughout the state, with a serious amount of late "side worm" injury, 

 due very largely to the reasons mentioned earlier in this paper. 



From the data at hand, this second brood appears at about the same 

 j)eriod every year, regardless of whether the season has been "early" or 

 not. If the grower depends on a single application aimed to control the 

 pest at this stage, dusting or spraying early in August would appear to 

 give him best results. Some growers this season made an application at 

 this time, and succeeded in reducing late "side worm" injury in those 

 blocks very successfully. 



For successful control of this pest, from our present knowledge of its 

 life history and habits, certain steps are essential: — 



