EXPERIMENTS WITH A VIEW TO CONTROLLING THE DISEASE. 



95 



small that no conclusions are drawn for this first season as to the effect of different methods of 

 pruning upon it ; but since this variety is particularly subject to crinkle, the pruning experiments 

 in succeeding years will show how far confluent Bitter Pit is influenced by the methods of pruning 

 adopted. 



6. At Albert Smith's Orchard, Deepdene, near Melbourne. 



On visiting Mr. Smith's orchard at Deepdene, about 7 miles from Melbourne, in August, 1911, 

 I found him cutting back all his Cleopatra trees on account of Bitter Pit, in order to re-graft them. 

 He informed me that the fruit was so badly pitted that it was simply useless as a commercial 

 crop. There were four rows altogether, and he had cut them all back, with the exception of 

 three in each row, when I stayed his hand, as I saw they would be very useful for experimental 

 purposes. On explaining the matter to him, he kindly allowed me the use of the trees, although 

 it interfered with his plans, and I have to express my indebtedness to Mr. Smith for his public 

 spirit in thus furthering the investigation of Bitter Pit. 



The immediate object of the experiment was to leave the trees unsp rayed, as they were 

 so very susceptible to the disease, and thus test the question which had been raised as- to 

 spraying, particularly with arsenical compounds, being the cause of Bitter Pit. As the trees 

 were in a corner of the orchard they were ideally situated for this purpose, and, in order to 

 utilize the plot as much as possible, I also tested the effect of different methods of pruning ; 

 leaving, however, the plot in the very corner unpruned, so as not to interfere in any way with 

 the results as regards Bitter Pit from non-spraying. 



The plan of the block of twelve trees is as follows : — ■ 



(Paddock Fence.) 



(General Orchard.) 



0 



O 



0 



Hedge.) 



0 



0 



0 



a 

 <s 



Q 



0 



0 



0 





Light 



Leader 



No 





pruning, pruning. pruning. 



The results of the pruning experiments only will be given here, the effects of non-spraying 

 having been previously referred to. The soil of the orchard is a sandy loam, with a clay bottom 

 at a depth of about 18 inches. The trees are nine years old, and they were planted at a distance 

 of 20 feet either way, the stock being the Northern Spy. The pruning was fairly severe in 

 1910, and they were also summer pruned. The ground was ploughed once in October, and the 

 drainage is fairly good. 



The crop in 1911 was fully 2 bushels per tree of well-grown apples, but, as the grower expressed 

 it, " They were all left on the ground for Pit." Although the trees were unsprayed, there was a good 

 setting of fruit on the whole when I visited the orchard on 21st October. The trees were pruned 

 on 22nd August by Mr. E. E. Pescott, so as to be quite comparable with those pruned at Burnley 

 Horticultural Gardens, and exactly on the same plan of severe, light, and leader pruning, as already 

 explained, leaving one row unpruned as a check. 



Frequent visits were paid to the orchard in the interval, and great care was taken, not only 

 that the trees were left absolutely unsprayed, but when the general orchard was being sprayed that 

 none of the spray was carried in that direction by the wind. 



The fruit was picked on 10th March, 1912, when it was almost ripe, and as might be expected 

 from the absence of spraying, not only was every apple badly affected with Black Spot or Scab so 



