SPRAYING EXPERIMENTS AND APPEE DISEASES. 3 



tions with materials which must be used with them and disas- 

 trous results are secured in the hands of the purchasers. 



While a fairly settled policy has been reached as to the proper 

 time to apply the various sprays or combinations of sprays to 

 secure the greatest efficiency there is still insufficient data 

 with regard to some of these points, particularly as applied to 

 local conditions. 



The present publication constitutes the fourth report of the 

 results of a series of orchard spraying experiments designed 

 to secure additional data upon some of the points mentioned 

 above.* It has also seemed desirable to include in the same 

 bulletin certain observations which have been made during the 

 year upon apple scab and apple cankers. 



Spraying Experiments in 1913. 



During the past season the spraying experiments were con- 

 ducted in the same portion of one of the orchards as in pre- 

 vious years but included 238 instead of 139 trees used in 1912, 

 or 40 rows of 6 trees to the row, with otne tree missing in each 

 of two rows. The plots were changed somewhat to avoid a 

 supposed difficulty of the previous year. While, as will be seen 

 later, the results of the present year indicate that this idea 

 was incorrect it was thought that the relatively small amount 

 of scab appearing in 19 12 on the plot sprayed only with 4 

 pounds of arsenate of lead paste in 50 gallons of water might 

 be partially due to its location at the corner of the orchard 

 and thus better exposed to sunlight and drying winds. 



The trees were of the Ben Davis variety and are between 

 25 and 30 years old. They are now in a very healthy, vigorous 

 condition. For the last 4 years they have been well cultivated, 

 fertilized and pruned. In 1909 some renovation work was 

 done on them but previous to this they had been badly neg- 

 lected for several years. 



The 1913 experiments comprised 10 different plots. All 

 plots used for making important comparisons between fungi- 

 cides, except that sprayed with bordeaux mixture, consisted of 



* The previous reports are given in Bulletins 189, 198 and 212 of this 

 Station. The first two are now out of print and are no longer available 

 for distribution. 



