30 NEW YORK STATE MUSEUM 



sprayed twice and those sprayed once, accompanied by an increase 

 of 562 side wormy apples ; in other words, each apple worm suc- 

 cessfully evading the first spray appears to have produced approxi- 

 mately 5.6 side wormy fruit later. Similarly, a difference of 217 

 end wormy and 1963 side wormy will be noted between plots 

 sprayed three times and those sprayed once, there being a ratio of 

 1 to 9 between the increase of end and side wormy. Now, if we 

 bear in mind the importance of the first application in reducing the 

 end wormy (this comprises about two-thirds of the total wormy 

 fruit on unsprayed trees) from 20.95 to .349 or .353 per cent (the 

 former an average of three years' work with one spray, the latter 

 the return from four years' work), we can hardly escape the con- 

 clusion that the very best way of controlling the second brood is to 

 spray most thoroughly for the first. Some six years ago Professor 

 Ball of Utah estimated that under conditions obtaining in that state, 

 two sprayings during the first period mentioned above, namely, 

 within a week or ten days after the blossoms fall, are worth six to 

 sixteen times as much as three late ones. This ratio is approxi- 

 mately true for our conditions, though considerable variation may 

 be expected from year to year. Checks in the fruit from hail 

 storms, sun scald, or burning by insecticides or fungicides afford 

 easy and safe points of entrance for second brood larvae and have 

 a material bearing upon the production of sound fruit. All having 

 practical experience with this pest know only too well how quickly 

 the young apple worms take advantage of these opportunities. The 

 development of such conditions as those just mentioned or the 

 somewhat common occurrence of wormy apples in early July would 

 be ample justification for a treatment the latter part of that month 

 or early in August for the purpose of destroying second brood 

 apple worms before they can enter the fruit. 



Conclusions. A study of the data collected during the past four 

 years justifies the conclusion for the Hudson valley at least, that in 

 normal seasons when the crop is abundant or fairly abundant, one 

 thorough early spraying within a week or ten days after the blos- 

 soms fall and preferably early during that period, should result in 

 the production of 95 to 98 per cent of sound fruit. A slight gain 

 will accrue from a second treatment about three weeks later, and 

 additional returns may be secured from a third spraying the latter 

 part of July. The benefit from the latter two is comparatively small, 

 so far as the codling moth is concerned, though ample to meet the 

 cost of the poison and, in many instances, probably the expense of 



