THE PREVALENCE OF BITTER PIT IN RELATION TO THE WEATHER. 33 



The land is rich alluvial black soil, and an adequate supply of water to the orchard is provided 

 by means of irrigation. I am indebted for the excellent photographs to Mr. Peacock, manager of 

 the Bathurst Experiment Farm. 



VICTORIA. 



Bailey's Bergamot pear tree is shown in Fig. 21, growing in Glenone Orchard, Dromana. It 

 is 50 years of age, and in some seasons yields as much as 40 bushels of fruit. No trace of Bitter Pit 

 or " Crinkle" has appeared in the fruit. 



X. THE PREVALENCE OF BITTER PIT IN ITS RELATION TO 

 THE WEATHER SEASON 1914-1915. 



It has been a surprise to many orchardists that, during the season of drought through which 

 we have passed, and the small crop of apples produced, in many instances total failures, there should 

 nevertheless be a considerable amount of Pit. But as has already been pointed out, it is not a strong 

 transpiration in dry air, nor a weak transpiration on dry soil, that induces Bitter Pit. It is the amount 

 relatively to the water-supply which is the important factor, and when this amount fluctuates with the 

 varying humidity, the conditions for Pit are most favourable. If the table of rainfall is examined 

 it will be found that, notwithstanding the drought, during the two important fruit-growing months of 

 November and December, there was a rainfall of from three to six inches at all the experimental 

 stations, with the exception of Yanco. But the subsoil had become so dried up, that this rain did 

 not produce the result in the fruit it might otherwise have done, and its growth was by fits and starts, 

 not slow and steady. At the Burnley Horticultural Gardens, the first appearance of Bitter Pit was 

 observed in the Williams' Favourite variety early in December, when the apples were between one- 

 third and one-half grown. The disease was very pronounced even at that early stage. Lord Suffield 

 was also observed to be pitted about the same time, and this tree affords a good illustration of the 

 conditions under which Pit originates. It was grafted on to a Northern Spy stock in September, 

 1913, and bore a cluster of six fruits next season, two of which were removed in order to allow the 

 remainder to grow properly. It is an early cooking variety, and Figs. 27, 28 show it in the middle of 

 January, when ready for picking, with every fruit badly pitted. 



The greatest amount of growth in the fruit took place in November and December, when after 

 a very dry spell intermittent showers occurred, the rainfall reaching nearly three inches in December. 

 The rank growth of the fruit on a young tree bearing only a few apples indicated an excess of moisture. 

 Rapid growth of the tree is always accompanied by excessive transpiration, and when the loss of 

 water by transpiration exceeded the amount of the water supply, it produced the degree of concen- 

 tration of the cell-sap which resulted in Bitter Pit. 



Perhaps the most convincing way of showing the prevalence of Bitter Pit last season will be 

 not to make general statements which are necessarily vague, but to cite particular instances. In 

 the various experimental plots in the different States, where fruit was produced, the amount of Pit 

 has been accurately determined, and this will at least give some definite information as to its occurrence 

 under known conditions. 



The minimum and maximum amounts are as follows : 



Victoria N.S.W. Queensland S. Australia W. Australia Tasmania New 



Burnley Gardens. Bathurst. Stanthorpe. Blackwood. Mt. Barker. Tamar. Norfolk. 



5-50% li-20% 4-33% 3-12% 15-40% 7-46% 46-100% 



The above refers solely to apples, but in individual orchards the disease occurred in pears and 

 quinces. I am indebted to Mr. Carmody, Chief Supervisor of Orchards, for the varieties of pears 

 affected in Victoria. They were Beurre Bosc, Beurr6 de Capiaumont, Gansell's Bergamot, Golden 



