]our}ial of Agriculture. 



[ii April, 1910, 



investigation and experiment are required before any definite deductions 

 can be drawn as to the effect of different manures on the development of 

 this disease. 



It is a signifi.cant fact that the Bismarck variety of apple, which was 

 used in these experiments on account of its great liability to the " pit," is 

 a colonial seedling, having been reared at Carisbrook by Clarkson about 

 1878. While the rearing of seedlings, with a constitution adapted to with- 

 stand the inroads of bitter pit, seems foredoomed tO' failure, the reduction 

 of the root system, as much as is consistent with the healthy growth of the 

 tree, might prove a step in the right direction. 



The effect of sulphate of iron and .sulphate of magnesia was also tried 

 during the past season on Cleopatra apple trees in a (loulburn Valley 

 orchard. Each salt was used at the rate of 3 lbs. per tree and although 

 the sulphate of iron gave a deep green healthy colour to the leaves, with an 

 extra good yield, still there were " pitted " apples on all the trees and the 

 disease developed further in store. 



Six apple trees of the variety known as Annie Elizabeth were selected 

 at the Burnley Horticultural Gardens for testing the amount of bitter pit 

 present in the crop when ready for picking, and the effect of keeping the 

 fruit which did not develop the disease externallv while still on the trees. 



The fruit was gathered on 4th ^larch, 1909, and there were 237 apples 

 altogether, of which 160 were pitted and 77 sound. The sound apples 

 from each tree were placed in separate cases and kept in mv laboratory. 

 They were examined successively on 15th, 23rd, and 30th March when the 

 diseased were removed, and the following is the result: — 



Se\'en of the apples which were sound when taken from the tree developed 

 "pit" in II days, 40 more in 19 days, and 8 in 26 days, so that there only 

 remained 22 sound apples at the end of the month out of a total of 77 at 

 the start. 



The percentage of sound apples while the fruit was still on the trees 

 amounted to 32.5, but after being picked and kept for nearlv four weeks, it 

 was only 9.2 or about 91 per cent, of the total yield was pitted. There is 

 a row of this variety in the gardens particularly susceptible to bitter pit, 

 and since there is an occasional individual who considers that he has a 

 remedy for this disease, thev are verv convenient for practically testing such 

 theories. 



There is no doubt about the serious nature of this disease, and if a 

 thorough investigation is to be made, it will necessitate experiments e^ftend- 

 ing over several years to test the effects of different .stocks, different systems 

 of pruning, different manures, different soils, the chemical differences be- 

 tween pitted and sound fruit, and so forth, in addition to the continuous 

 observation of those varieties which are least susceptible to it. 



