EXPERIMENTS CONDUCTED WITH A VIEW TO CONTROLLING DISEASE. 43 



There is a very decided difference in favour of the light pruning, both in yield and Pit. The 

 unpruned trees bear such light crops, although practically free from Pit, that they are only retained as a 

 scientific standard with which to compare the others. The average yield of the lightly pruned trees is 

 fully twice that of the severe!}' pruned, and as regards Pit it is only about one-third that of the other. 

 The fruit on the single Cleopatra tree which had been unpruned for fourteen years was rather small, 

 but still marketable. Just as in the case of the manorial experiments, it is the individual trees with 

 small yields which raise the average of the Pit considerably, and if these were excluded in the lightly 

 pruned trees, the amount of Pit would be reduced to a minimum of 3 per cent. 



The single Cleopatra tree which was unpruned for the past fourteen years, bore a crop weighing 

 131 J Ibs. Of these only J Ib. was Pitted, so that the percentage of Pit was 0' 19. This is practically 

 the same as that for all the unpruned trees, and when the small size of the fruit is taken into account, 

 it justifies the inference that the nearer the Crab apple the less Pit, while the bigger and more succulent 

 the apple, i.e., the more artificial, the greater the amount of Pit. 



9. AT YANCO GOVERNMENT FARM, NEW SOUTH WALES. 



Since 1912 the four young Cleopatra trees have been pruned similarly, and, although there is 

 only an individual tree for each system of pruning, yet the results are shown under irrigation 

 conditions. The trees were pruned on 16th September, 1915. No manure was applied except grey 

 field peas, sown at the rate of one bushel, and 60 Ibs. of superphosphate to the acre, then ploughed in 

 during the spring. 



The trees were irrigated during November and December, 1915, and January and February, 

 1916. The mature apples were harvested on 16th February, and the remainder of the crop on 28th 

 February. 



Unfortunately, the yield from each individual tree was lost, but the windfalls were accurately 

 recorded. This will give some idea of the relative amount of Pit. One case from each tree was also 

 forwarded to me in Melbourne on 22nd 'February for placing in the Government Cool Stores. They 

 were free from Pit when packed, but on being examined by me on 28th February a few were found 



pitted. 



TABLE XXIII. 



DEVELOPMENT OF PIT IN WINDFALLS ACCORDING TO DIFFERENT METHODS OF PRUNING. 



Pitted. Per cent. Pitted. 

 No. 



4 4-8 



5 4-7 

 2 3-8 



TABLE XXIV. 

 DEVELOPMENT OF PIT IN ONE CASE FROM EACH TREE AFTER KEEPING FOR Six DAYS. 



Pruning. Apples in Case. Clean. Pitted. Per cent. Pitted. 



No. No. No. 



Severe 140 129 11 7-8 



Light 139 137 2 1-4 



Leader 154 153 1 "6 



Unpruned 155 154 1 '6 



The trees were planted in the winter of 1908, and are now producing sufficient fruit to show how 

 the development of Pit is affected by different modes of pruning. The orchardist at Yanco Experi- 

 ment Farm is able to give approximately the yield of the different trees, viz., severely pruned, 7 bushels ; 

 lightly pruned, 8i bushels ; leader pruned, 9 bushels ; and unpruned, 10 bushels. And in accordance 

 with the information derived from the windfalls, he found that trees 1 and 2 showed the greatest 

 amount of Pit. 



