METHODS IN CODLING MOTH EXPERIMENTS. 55 



It will be noted in Table I that on the check rows, where all the 

 apples were computed, only 7 per cent were sound, and when only 

 the picked fruit was used the sound apple- amounted to 24 per cent. 

 This was due to the large amount of wormy fruit found on August 4 

 and September 23. The percentage of improvement is secured by 

 subtracting the percentage of sound fruit on the check row. made 

 by each method of computation, from that secured on the treated 

 rows. This gives a balance of 3 and -i per cent as a result of the 

 different methods of computation, the larger percentage in the results 

 being in favor of considering the entire crop. 



In Table II, if the same methods are followed, a 4 per cent differ- 

 ence is shown, but this increase is in favor of the method where only 

 the picked fruit is used. If it is assumed that the correct method is 

 to have all of the fruit grown on the tree considered in deciding the 

 percentage value of treatment, then the other method show- 4 per 

 cent decrease in sound fruit in Table I and 4 per cent increase in 

 Table II. It is therefore evident, as shown by these tests, that the 

 error made by using only the picked fruit may range from none to 

 8 per cent in any experiment. 



THE CONTROL OF THE CODLING MOTH IN THE ARID REGIONS. 

 By E. D. Ball. Logan, Utah. 



The codling moth (Garpocapsa jiomoitella L.) is by far the most 

 serious pest with which the apple grower in the arid region^ has 

 to contend. The unsprayed orchards will average, taking one year 

 with another, fully one worm for each apple. In a year of abundant 

 crops there will be some apples remaining sound, but the inevitable 

 light crop following this is likely to have three or four worms to an 

 apple. 



That thorough and persistent spraying will control the codling moth 

 has been demonstrated so many times as to appear at first sight almost 

 axiomatic, yet when the writer took up the work in Utah, in the fall 

 of 1902, he found a very deplorable state of affairs existing through- 

 out the State. The codling moth had evidently been increasing in 

 Dumber and destructiveness for a series of years, and many of the 

 leading fruit growers, who had formerly handled it with ease, were 

 now meeting with very indifferent success or failing entirely to 

 control it. Numerous instances were cited where from 4 to 6 or even 

 more sprayings had failed to save the crop, while those who suc- 

 ceeded in getting 75 to 85 per cent of the picked fruit sound were 

 considered highly successful. To add to the confusion, the cry had 

 gone forth that the poisons were adulterated, thai early sprays were 

 of little value, and that three or even four or more broods were to be 



