ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 



107 



In this experiment a slightly smaller percentage of larvae entered 

 at the calyx end of the apple on the lime-sulphur demonstration 

 plat than on the one-spray plat, the percentages being 6.70 and 8.49, 

 respectively. As will be noted under the above discussion of wormi- 

 ness of the apples, a coarse-spray nozzle and a high pressure were 

 used for all applications on all the sprayed plats. Such treatment 

 would therefore be expected to result in a lower percentage of larvae 

 entering at the calyx end on the demonstration plat than if a mist 

 spray had been used, as was done in the foregoing experiments. The 

 total number of larvae on Plats I, II, III, and IV are, respectively, 

 970, 3,215, 1,543, and 12,917. 



In protecting the calyx end of the apple there is shown a difference 

 between the two treatments of 1.02 per cent in favor of the demon- 

 stration, which is a greater difference than occurred in any of the 

 other experiments. This result is probably largely due to the use of 

 coarse-spray nozzles on all sprayed plats as mentioned above. The 

 demonstration treatment saved a total of 95.28 per cent of the crop, 

 which was 11.11 per cent more than that saved by the one-spray 

 treatment. The efficiency of the one-spray and demonstration 

 treatments in preventing worminess is shown in condensed form in 

 Table XVIII. 



Table XVIII. — Efficiency of the demonstration and one-spray treatments against the 

 codling moth as shown by the percentage of wormy apples. Wichita, Kans., 1911. 



Plat No. 



I. Demonstration 



III. One-spray 



IV. Lnsprayed 



Percentage of wormy apples. 



Calyx. 



0.32 

 1.34 



42.10 



Side. 



4.11 

 12.88 

 17.05 



Stem. 



0.29 

 1.61 



10.64 



Total. 



4.72 

 15.83 



69.79 



number J£jJhL 



VSP fflSi 



970 



1.543 



12,917 



20,545 

 9,745 

 18,506 



SUMMARY OP RESULTS. 



The percentages of fruit free from codling moth and plum curculio 

 injury on the demonstration, one-spray, and unsprayed plats from 

 the several localities are given for comparison in Table XIX. The 

 average percentage of fruit free from codling-moth injury for the four 

 orchards gives for the demonstration treatment 96.72 per cent as 

 against 90.76 per cent for the one-spray method, a gain of 5.96 per 

 cent in favor of the demonstration. The average percentage of fruit 

 free from this insect on the unsprayed plats was 52.70, making a gain 

 in favor of the demonstration plats over the unsprayed plats of 44.02 

 per cent. 



