5fi 



BITTER PIT INVESTIGATION. 



Reinette de Canada, Gravenstein, Duchess d'Oldenburgli, and Shorland Queen, 

 and the effect of these stocks on the development of Bitter Pit is being 

 observed. 



(e) Over manuring or heavy manuring with stable manure. — " Heavy manuring with 

 stable manure, and watering, with heavy pruning, cause the disease." 



(/) Climatic conditions, such as a wet spring followed by a dry summer, or the shock 

 caused by a sudden period of dry weather. — " Continued drought so that the 

 trees begin to suffer, then a sudden and heavy fall of rain causing the trees to 

 start a second growth will cause it at any time." "I thought at one time that 

 it was due to excessive moisture, but that is not the case, as the past season 

 (1910-11) was the wettest known here, and Annie Elizabeth, being generally the 

 worst affected, were clean." £< The conclusions I have come to are, that if you 

 manure heavily with nitrogenous manures, and have a dry spell followed by 

 heavy rains, you will get Bitter Pit, but if the season is fairly wet like last year 

 (1910), so that there is no check to the growth, you have little or no Bitter Pit." 



(g) Light crops caused by bad setting. — " I have never met an apple absolutely free, 



especially if a light crop with large fruit." 



(h) Absence of lime or some other necessary chemical ingredient lacking in the soil. — ■ 



" 1 have noticed that, where the soil and subsoil is calcareous, the most susceptible 

 apples are comparatively free from Pit." 



(i) Too much imperfectly prepared food and vegetable indigestion.— " Having noticed 



that Pit occurs — (a) on fruit of young trees ; (b) when there is a light crop of large 

 grown fruit ; (c) on fruit from trees in rich black ground, and (d) on fruit on thick 

 artificial spurs or spurs near a strong flow of sap, I am of opinion that the trouble 

 is due to too much coarse or imperfectly prepared food." 

 (j) Nature of soil. — " Heavy soils badly worked and badly drained favour the Pit." 

 " it seems to be constitutional with certain varieties of apples. If these varieties 

 are planted on heavy wet soil Bitter Pit is always prevalent. If the same 

 varieties are planted on light well-drained soil they are mostly clean." " I have 

 trees growing on rich moist soil very badly affected, and, at the same time, the 

 same variety growing on a poor ridge quite free." 



The cause generally is well summed up in the following opinion from the Hon. T. Playford, 

 one of the oldest fruit-growers of South Australia : " Bitter Pit is mainly, if not altogether, caused 

 by a superabundance of sap in the tree, and of juice in the fruit. I first saw it in 1860. I have 

 found it worse in Cleopatra, Northern Spy, and London Pippin. The early sorts are mostly free 

 from it, except Gladstone. It always occurs in large fruit. I had two Cleopatra trees growing side 

 by side, one with a good crop of moderate sized fruit, one with a small crop of large sized fruit ; the 

 smaller fruit, when stored, never developed the Pit, the larger were nearly all rendered unsaleable 

 by it. This is a sample of my experience with all other kinds— it is the universal rule. This has 

 caused me to come to the conclusion that the cause of Bitter Pit will be found in the sap of the tree 

 and the juice of the fruit. It is not infectious— is not caused by insect pest or fungoid growth, so far 

 as I have been able to ascertain." 



REMEDIES PROPOSED. 



In offering opinions on the probable causes of Bitter Pit, some of the growers have ventured 

 to propose remedies. 



Mr. A. G. Campbell, Pomonal, Victoria, writes — "Remedies practised with success by 

 myself are drainage of black ground, light cultivation, even rolling of rich ground, and an open 

 system of pruning with laterals to bear fruit." 



