98 



BITTER PIT INVESTIGATION. 



The results of a single season show that the hard-pruned Cleopatra trees have less than half 

 as much Pit as the medium pruned, while those not pruned at all have considerably less than any 

 of the others. 



There is one special Cleopatra apple tree (Fig. 123) which is now sixteen years old, and was 

 loaded with fruit. It was pruned for the first six years, and has been left unpruned for the past 

 ten years. The quantitj of fruit is much higher than the average, but it is small, the average size 

 being only about 2 inches. It is interesting to note, however, that it shows an exceedingly small 

 amount of Pit, only £ per cent. It will be observed from the photograph that the branches are all 

 pendent, and it bears out the contention of those orchardists who maintain that, when the bearing 

 branches are more or less bent, and pruning is not directed towards rigid uprightness, the liability 

 to pit is very much lessened. 



8. At Government Experiment Orchard, Blackwood, South Australia. 



The trees in these plots were planted in August, 1910, and pruned the same year rather 

 severely. The varieties chosen are Cleopatra, Munroe's Favourite or Dunn's Seedling, Jonathan, 

 Scarlet Nonpareil, and Kome Beauty. There is no fruit as yet, but the nature of the experiments 

 may be given. 



1. Pruned every year — Fruit not thinned. 



2. Pruned first three years, then not pruned — Fruit thinned. 



3. Never pruned — Fruit not thinned. 



4. Pruned three winters, then every second winter. 



5. Pruned every winter, and summer pruned. 



. C. — EXPERIMENTS WITH STOCKS. 



In order to determine the influence of the stock on the development of Bitter Pit in a 

 satisfactory manner, a longer period of time would be required than is available, but I have adopted 

 a method for getting results more quickly, and which will at least indicate if the stock is an important 

 factor. 



Fortunately, a series of experiments are being conducted in South Australia by Mr. Quinn, 

 which will show the effect of the stock on Bitter Pit during a number of years, and in a thorough 

 manner. 



Not only are experiments being carried out with apple-tree stocks, but also with pear trees. 

 Some varieties of pear trees are affected with Bitter Pit, and in the same orchard there are 

 individual trees which have always been free. Grafts from the affected trees will be worked on 

 the clean trees, and vice versa, to see the result. 



As showing the influence of the stock on the scion, I have selected the Gravenstein apple tree. 

 It is a strong grower, forming a large spreading head, but it has the habit of producing a ribbed 

 trunk and twisted and deformed branches. So much is this considered to be a hereditary quality 

 of this variety, that Mr. Lang, in describing it in the Agricultural Journal of Victoria for January, 

 1905, writes : — " A peculiarity of this tree is the bossed and uneven appearance of the trunk and 

 main branches, many of the branches having a twisted and gnarled appearance." As long as this 

 variety was grafted on to Northern Spy stock, it developed the deformity, as shown in Figs. 126, 

 127, 128, but, whenever it was grafted on the Spy roots, there was no appearance of it (Fig. 129). 

 The trees photographed were about thirteen years old. There were about 80 of them growing in 

 this orchard, and wherever they were root-grafted they were perfectly normal. The soil is alluvial, 

 with clay about 3 feet deep. The stocks used were taken from healthy well-grown Gravenstein 

 trees, and in the one row (Fig. 126) with the same soil, you can easily pick out those not root-grafted 

 from their twisted and contorted branches. The Gravensteins one usually meets with are deformed, 

 and Mr. Peacock, of the Government Farm, New South Wales, writes — " We have no Gravensteins 

 on seedling stocks or Spy roots, but the tree on the Spy stock is badly twisted." 



