METHODS IN CODLING MOTB EXPERIMENTS. 53 



Two papers were then presented on codling-moth investigations, 



after which they were discussed. 



REMARKS ON METHODS USED IN CODLING MOTH EXPERIMENTS. 

 By A. F. Burgess, Columbus, oiiiu. 



In the- great mass of data already published concerning the codling 

 moth (Carpocapsa pomonella L.) it will be found that numerous 

 standards have been used for determining the results of spraying. 

 Many entomologists have followed the system of basing results -im- 

 ply on the number of picked apples which are wormy or sound on 

 treated and check trees, while in other cases samples of one or more 

 bushels of picked fruit, supposed to represent average conditions, 

 have been counted and have served for making the determinations of 

 the benefit derived. Sometimes an estimate of the wormy and sound 

 dropped fruit has been made at the time of harvesting, but in the 

 majority of cases no accurate account has been kept of the wormy 

 fruit that dropped early in the season. 



Undoubtedly this lack of data has been largely due to the fact that 

 most entomologists who have attempted such experiments have not 

 had at their disposal the necessary time to make complete counts of 

 fruit. In some sections, also, horticulturists pay little attention to 

 the fruit which drops early in the season, considering it a necessary 

 evil when the crop is light and a direct benefit when the crop is 

 heavy, as it saves labor in thinning. It wotdd appear, however, if 

 an accurate statement of the benefit derived by treatment is to be 

 made, that all fruit growing on the trees should be accounted for. 



In order to illustrate the case more fully, two tables are submitted, 

 showing the percentages of benefit from spraying that may be deduced 

 from the two different methods. Table I gives the treatment, in 

 1903. of two rows of 10 trees and 10 check trees in the orchard of 

 Mr. R. L. Hudson, at Delaware, Ohio, with Disparene and Bordeaux 

 mixture, also the number of wormy dropped apples, the wormy and 

 sound picked fruit, and the percentages of sound fruit, using all the 

 apples as a basis or by using only the picked fruit. 



Table II gives similar data taken in the orchard of Mr. Oscar 

 liaise, at Birmingham, Ohio, in 1905. The crop in the Hudson 

 orchard was short, while that in the other orchard was good, but 

 nearly twice the number of trees were used in the former orchard. 



In Table I no sound fruit was recorded when the count of the wind- 

 falls was made in August. So few sound apples were found that no 

 record was made, but in later experiments the numbers were carefully 

 noted, as is shown in Table II. 



