162 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



In 8 of the 11 experiments, the percentage of sound fruit is above 

 90. In one instance (Va. '09), the lessened efficiency of the treatment 

 was due to the effect of a serious hail storm greatly favoring the side 

 entrance of the fruit by the larvse. Spraying results must, of course, 

 be considered in connection with the severity of the insect. The 

 percentage of sound fruit on the untreated trees of the respective 

 experiments is shown for comparison. The average of the percentages 

 of sound fruit for the one-spray method for all localities is 92.86 as 

 compared with an average of 58.44 per cent of sound fruit on the 

 untreated plats. 



A few workers have also made observations on the effect of the one- 

 spray method in controlling the plum curculio. A surprising degree 

 of efficiency has been obtained by a single spraying as the petals fall, 

 and can only be accounted for on the supposition that practically 

 all the beetles are out and feeding at that time, and thus are practically 

 exterminated. The average percentage of fruit free from curculio 

 injury for the several experiments in which this point is reported, is 

 81.15 as compared with 51.76 per cent of sound fruit on untreated 

 plats. 



An interesting question comes up in this connection. Many records 

 on unsprayed trees show that from two-thirds to three-fourths of 

 the first brood larvse of the codling moth enter the fruit at the calyx 

 end. Assuming that all of the young larvae entering the calyx are 

 killed, there still remains some 25 to 30 per cent of larvse which nor- 

 mally enter the fruit at the side. Based upon the percentage of sound 

 fruit obtained, these also have been destroyed. Perhaps sufficient 

 spray from a single application remains on the foliage and fruit to 

 destroy the young larvse as they are hatching some three or four weeks 

 later. 



Notwithstanding the excellent showing made by the one-spray 

 method, it is another question under Eastern orchard conditions 

 whether its use should be recommended. The necessity for several 

 applications of fungicides adds but little to the expense of making 

 additional treatments with arsenicals. If plant pathologists should 

 be able to reduce fungicidal apphcations to one treatment, following 

 the dropping of the petals, there is no question but that the one-spray 

 method would come into large favor by orchardists, but it should be 

 remembered that the results, above indicated, have been obtained in 

 the course of experimental work where particular attention was given 

 to thoroughness; while such results could, of course, be secured by 

 orchardists, they will, for the most part, fail to obtain such a high 

 percentage of sound fruit. I do not believe that entomologists would 

 at present be justified in radically, changing present spraying schedules 



