108 



BITTER PIT INVESTIGATION. 



The side shoots of a tree, when bearing fruit, are generally bent down by the weight of it, 

 and this bending of the shoot will exercise an influence on the supply of food material. These side 

 shoots when they have made fairly long and rapid growth are known as Laterals, and the question 

 is, what effect has the pruning of the laterals on the development of Bitter Pit ? 



Of course, there are a number of orchardists who consider that pruning has no influence on 

 Bitter Pit, but, if we take the opinion of those who have specially referred to it in their replies to 

 questions, it is found that lateral pruning is not recommended. In Victoria, the following replies 

 have been received :— " I think light pruning makes a great difference in the amount of Pit, leaving 

 plenty of lateral growth." "To leave most of the long laterals with fruit spurs attached is 

 beneficial." ££ I have always pruned with plenty of laterals, and have had less pit than my 

 neighbours." "When laterals are left long or unpruned altogether (if not too long) a larger 

 percentage of clean fruit will result." "Prune lightly, leaving laterals to run sap off, and the 

 disease is lessened 75 per cent." " I fancy it is the chief thing to get bends in the leaders, and do 

 away with the upright ones as much as possible, and encourage laterals. It exhausts the rapid 

 flow of sap, and the fruit matures gradually." " I find in Cleopatras leaving their fruit on the long 

 laterals reduces the disease wonderfully." 



In New South Wales, no special reference is made to it, and in South Australia it is indirectly 

 referred to. " I left one tree in the middle of 2 acres of Cleopatras unpruned for ten years, and 

 picked more clean apples from that one in a bad season than from ten of the heavily pruned trees." 

 cc The harder trees are pruned the more subject they are to Pit, but a great deal depends on the 

 method of pruning and treatment of laterals." In West Australia, it is not noted ; and in Tasmania 

 the direct question was sent out to various Fruit-growers' Associations by the Director, viz., " Have 

 you found any appreciable effect in the diminution or otherwise of Bitter Pit from the retention of 

 lateral branches when pruning?" Out of eleven replies received, four found no difference, and the 

 remaining seven found less Pit on the left laterals. " I always retain in pruning lateral branches 

 and spurs, and, as a rule, do not lose in 2,000 bushels 1 per cent." 



In a paper on " Lateral Growths," read before the Clarence Board of Agriculture by 

 Mr. Goodwin (35), it was stated and concurred in by several of the growers present that Bitter Pit 

 had never been found in an apple at the end of a lateral shoot. This is not always so, as I found 

 one of the Garden Eoyal variety at the Burnley Gardens. The tree yielded about a bushel case 

 of fruit, and it was the only apple on the tree with Bitter Pit. It was the only fruit at the end of 

 the lowest lateral out of one of the main branches, but it is generally the case that the terminal 

 fruit, at least, on laterals is free from Bitter Pit. 



In conclusion, the Principal of the Burnley School of Horticulture approves of the retention 

 of a good lateral system, and only prunes the lateral growths — 



(1) When they interfere with each other ; 



(2) When they are overcrowded ; 



(3) When they are too high in the tree ; and 



(4) When they have a long unproductive reach near to the main limb. 



But the relationship between this practice and Bitter Pit has yet to be determined by exact 

 observation and experiment. 



The experiments here mapped out and already begun may be extended as found necessary. 

 It is evident, however, from the very nature of the case, that the results of these experiments may 

 modify the views expressed, and visits paid to the various States during the growing season may 

 bring a number of new facts to light. But I considered it desirable and profitable, even at this 

 early stage of the inquiry, to show the progress made " as far as my investigations go." 



