EXPERIMENTS WITH A VIEW TO CONTROLLING THE DISEASE. 79 



published in April, 1909, in " Der praktische Ratgeber im Obst und Gartenbau " (G). The 

 recommendations are justified from what we know of the disease in Australia : — 



1. Light pruning, taking care to admit light at the top. 



2. Thinning not to be overdone. 



3. Growth not to be stimulated by fits and starts in the growing period, and water or 



liquid manures not to be applied too late in the autumn. 



4. Not to pluck the fruit too late. 



5. Not to have the store-room too dry. 



6. To re-work, that is, to graft another variety on the old stock. 



XXII. — EXPERIMENTS WITH A VIEW TO CONTROLLING THE DISEASE. 



Since the investigation of Bitter Pit is conducted with the twofold object in view of determining 

 the cause and devising a remedy, there have necessarily been researches in the laboratory as well 

 as experiments and systematic observations in the orchard. From an investigation of the minute 

 structure of the apple, and particularly from the discovery of the wonderful network of conducting 

 tissue in the apple, pear, and quince, a flood of light has been thrown on the cause of Bitter Pit, 

 and not only on this disease but several other obscure diseases of " pip fruits." The lines along 

 which experiments are being conducted in the different States of the Commonwealth, chiefly with 

 manures, pruning, various modes of cultivation, irrigation, and the employment of different 

 stocks, are not only promising, with reference to the mitigation of this particular disease, but they 

 cannot fail, from the varied conditions under which they are carried out, to be of great indirect 

 benefit to the apple-growing industry as a whole. 



As my official appointment only dates from August, 1911, it was rather late in the season 

 to carry out some of the experimental work in a proper manner. Nevertheless, Experiment Stations 

 were secured in the different States, with the exception of Queensland, which did not at first join 111 

 the investigation with the other States, but arrangements have now been made whereby this omission 

 will be rectified. 



Experiment Stations are now established in Victoria at Burnley Horticultural Gardens, 

 Box Hill, and Deepdene ; in New South Wales at Bathurst Experiment Farm ; in South Australia 

 at the Government Experiment Orchard, Blackwood ; in Tasmania at a Tamar .River Valley 

 orchard ; in West Australia at Mount Barker Estate ; and in Queensland at Stanthorpe. 



The series of experiments include the following : — 



A. — Manurial. E. — Irrigation. 



B. — Pruning. F. — Cold Storage. 



C. — Stocks. G. — Miscellaneous. 



D. — Cultivation. 



Under each of these headings, the work done and the results obtained for one season will be 

 recorded, but it must always be understood that no final conclusions can be drawn from such a 

 limited experience. From the very nature of the work, these results will only supply a basis from 

 which, as a starting point, the value of future experiments will be determined. 



The variety of conditions under which these experiments are conducted — of soil and climate, 

 heat and moisture, from Tasmania in the South to Queensland in the North, from New South Wales 

 and Victoria in the East to Western Australia in the West— will supply valuable data as to the effect 

 of environment on the prevalence of the disease. Since the conditions under which the results 

 have been obtained are so important, I have endeavoured in this first Report to give in connexion 



