EXPERIMENTS CONDUCTED WITH A VIEW TO CONTROLLING DISEASE. 41 



AMOUNT OF PIT. 



A glance at the table and the summary will show in an unmistakable manner, that the mode of 

 pruning when the tree is in bearing, exercises an important influence on the development of Bitter 

 Pit. While the severely pruned trees yielded fruit affected with Pit to the extent of 22 per cent., 

 those that had been lightly or leader pruned were only affected to the extent of 4-6 per cent. From 

 the very nature of this disease one cannot expect absolutely to prevent it, since we cannot exercise 

 complete control over the flow of sap, but the small amount of Pit accompanying light or lateral 

 pruning is very satisfactory. 



YIELD IN RELATION TO MODE OF PRUNING. 



As regards the yield, the smallest was obtained from the unpruned trees. Among the pruned 

 trees, severe pruning gave the lowest yield, although light pruning produced practically the same. 

 The leader-pruned trees gave the highest yield, along with the smallest percentage of Pit. 



INDIVIDUAL TREES IN RELATION TO PIT. 



There was one tree which stood out among all the others as having evidently made the most 

 growth with the lightest crop and apparently the greatest amount of Pit. No. 10 tree had the lightest 

 crop of all the pruned trees, made the greatest growth, bore the largest and ripest fruit, and was the 

 worst pitted, reaching 32 per cent. 



There is a correlation between these various characters, for the light crop and the large fruit, 

 together with the more rapid growth in a given time, are associated with those physiological disturb- 

 ances which produce Bitter Pit. 



WINDFALLS AND PIT. 



If we consider the amount of Pit in the fruit picked off the trees, and this is the commercial aspect 

 of it, we find that it is invariably less than when the windfalls are included. 



The percentage of Pit in the windfalls is much higher than that of the fruit on the tree. In the 

 severely pruned trees the difference is less marked than in the other methods of pruning. Although 

 the relative proportion of windfalls to the different modes of pruning has not been observed sufficiently 

 long or extensively to enable us to draw definite conclusions, yet it is worthy of note that the 

 proportion in these experiments is 17 per cent, in the light and severe pruning, while it is about 12 per 

 cent, in the leader and no pruning. 



8. AT GOVERNMENT FARM, BATHURST, NEW SOUTH WALES. 



This is the fifth year in succession in which these experiments have been carried out with Cleopatra 

 trees, and the results should show the relative merits of the different systems of pruning, as far as yield 

 and Pit are concerned. In the early stages of the experiment the severely and lightly pruned trees 

 were unfortunately interchanged, but for the last three seasons the plots have been pruned as shown 

 in the tables. The unpruned trees show the effect of non-interference for five seasons. These trees 

 are now about twenty years old, of the same age as those used in the manurial experiments. 



TABLE XX. 



SEVERE PRUNING TEN CLEOPATRA TREES IN Two Rows. 

 Fruit. 



Tree. Sound. Pitted. Total Fruit. Per cent. Pitted. 



Ibs. Ibs. Ibs. 



48 .. 4J .. 52| .. 8-57 



.... 27 .. 12" .. 39 .. 30-76 



Row H 3 .... 72 .. 3 .. 75 .. 4- 



.... 78 .. 8 .. 86 .. 9-30 



.... 36 .. 2J .. 38J .. 5-88 



