

THE CONTROL OF BITTER PIT. 77 



The lateral system of pruning was found by experiment to considerably reduce the Pit ; and 

 the retention of the laterals, as far as practicable, is therefore recommended on the following grounds : 



1. In the case of 14 laterals on 14 different varieties selected indiscriminately at an early 



stage in the Burnley Horticultural Gardens, it was found that when the fruit was 

 picked not a single apple borne on the laterals was pitted, although in some cases 

 (e.g. Shockley) the fruit borne on the fruit-spurs arising from the main limbs was 

 badly pitted. Last season there was only one of these selected trees in bearing, 

 and the same lateral bore only two fruits, of which one was pitted. 



2. It is a matter of common observation that there is a greater liability to Pit when the lateral 



is pruned than when left unpruned. 



' 3. It has also been observed that the Pit is worse on spurs arising from the main branches 

 than on the laterals of the same tree. 



4. It is found that when trees are laterally pruned and well spread out all round, they 



carry more fruit than when it is produced only off the main branches. 



5. The Statesman is a variety which sometimes Pits very badly, and one tree 18 years old 



was cropped for the first time on the laterals last season. The bearing surface was 

 thereby at least doubled, and the crop was not only more than twice that of any 

 previous record, but not a trace of Pit was discovered. 



It has been invariably found that severe pruning of the fruit-bearing tree increases the Pit. 

 Therefore a system of light pruning is to be recommended. 



Besides the pruning, the general management of the orchard in respect to manuring, draining, 

 and cultivation has a bearing upon the development of Bitter Pit. 



Active nitrogenous manures, such as stable manure and fish manure, are found to increase the 

 Pit when applied in excess. They cause rank growth with superfluity of water, and such conditions 

 when the fruit is growing are eminently favourable to Pit. Such manures should be avoided and 

 nitrogen supplied in the slower form of green manuring. 



In an apple orchard we cannot adopt a system of rotation of crops, but there may be a rotation 

 of manures, which will practically serve the same purpose. Every year, when the orchard is in full 

 bearing, an application of ordinary superphosphate and sulphate of potash at the rate, on an average, 

 of 2 cwt. and 1 cwt. per acre respectively will be found beneficial. 



Every second year green manuring with field peas to supply nitrogen and humus, which will 

 conserve moisture, is recommended. Also a dressing of fine unburnt limestone, such as is supplied 

 from Curdie's Inlet, at the rate of, say, one ton per acre can be usefully applied. 



Lime may also be applied as burnt or slaked lime at the rate of 10 to 12 cwts. per acre instead of 

 unburnt limestone. Such lime acts more quickly, and should be applied in autumn. In connection 

 with lime, it should be remembered that on soils well supplied with humus the lime, by accelerating 

 nitrification, may obviate entirely the need for nitrogenous manures. In such cases a further applica- 

 tion of nitrogenous manures by undue stimulation of growth may encourage Bitter Pit. 



In wet soils drainage is necessary to keep the roots healthy and active by getting rid of the sur- 

 plus water and thus allowing the air to enter. It is found as a matter of practical experience that 

 drainage tends to reduce the Pit, and it is observed that in those portions of an undrained orchard 

 which lie low and are very wet in winter the disease is worst. 



Ploughing and cultivating the land is sometimes said to encourage Pit, owing to the strong and 

 vigorous growth produced. But it will be found that the ill-effects are not due to cultivation, but to 

 some other faulty treatment of the tree itself. 



Apart from its influence in the improved physical condition or the increased chemical activity 

 of the soil, tillage has an important effect on the transpiration of the tree. It increases the capacity 



