APPLE SPRAYING EXPERIMENTS IN I915. 177 



omission of the first spray were only slight and probably within 

 the limits of experimental error. In one case there was slightly 

 more and in another slightly less. In 1912, or the first season 

 in which the experiment was carried out, quite striking results 

 were obtained showing the value of the first application. 



In 1915 scab was controlled equally well on both plots, it 

 being reduced in each instance, when compared with the check 

 plot from 5 per cent to a little over one-tenth per cent. As 

 has already been mentioned it was not possible to determine 

 just when the ascospores of the scab fungus reached maturity 

 in the orchard on the fallen leaves of the season before, but 

 it was plainly some days after the application of the first fun- 

 gicidal spray, or the one omitted on plot 2, as shown by labor- 

 atory studies of the material collected and taken to Orono. 



The evidence secured on this point in the past plainly indi- 

 cates that the omission of the application when the blossom 

 buds are showing pink may result in a large increase of scab. 

 On the other hand the results of the past season again show that 

 no orchardist should fail to carry out the remainder of the 

 season's spraying program, if for any reason the fir?t appli- 

 cation was omitted. 



Lime-sulphur vs. Bordeaux Mixture. - 



As has already been stated plots 1 and 7, sprayed with 

 these two materials, in connection with the unsprayed check, 

 form the basis for determining the relative merits of the other 

 spray combinations used. It is of interest to note, however, 

 that upon a variety of apples like the Ben Davis where both 

 the foliage and fruit are particularly susceptible to spray injury 

 lime-sulphur continues to show marked superiority. Scab con- 

 trol in each case was nearly perfect, but on account of russet- 

 ing of the fruit less than 22 per cent of perfect apples were 

 obtained from the use of bordeaux mixture, while over 89 

 per cent of the same grade of fruit was secured where lime- 

 sulphur was used. 



Another fact worthy of comment is that in this season where 

 only a small amount of scab developed on the unsprayed check 

 the amount of russeting produced by the lime-sulphur itself 

 more than offset its beneficial results in scab control, for over 

 91 per cent of perfect apples were obtained on the check plot. 



