64 BITTER PIT INVESTIGATION. 



GENERAL SUMMARY. 



We are now in a position to draw conclusions from the results of five years' experimental work in 

 the orchard and research work in the laboratory. These results go to show that the practical part 

 of the investigation has been successful. 



The oversea shipment of fruit may now be undertaken without the risk of apples becoming pitted 

 or over-ripe on the voyage, and the growing of fruit in the orchard may be so controlled that the 

 development of Pit will be considerably reduced. As to the cause of Bitter Pit, there are many 

 contributing factors of environment ; but if that theory is best which best explains and co-ordinates the 

 greatest number of known facts, then the one brought forward is the most probable. Bitter Pit 

 is due to over-pressure of water in the constitutionally weakened tissue of the cultivated apple. 



COMMON NAMES OF BITTER PIT. 



Various names have been given to this disease in different countries. In Australia, Britain, and 

 South Africa it is known as "Bitter Pit," but if priority is recognized in connection with common 

 names, then it was first described by the Germans under the name of "Stippen." In the United States 

 of America it was first referred to as "Baldwin Spot," because that variety was particularly susceptible 

 to it ; and in Canada it was described as a "dry rot." In France it is known under the names of 

 ''Points brim de la chair" (brown spots of the flesh) and "Liege" (cork disease) with reference to the 

 cork-like nature of the cells. 



In using common names there is always a danger of applying them to diseases which are not 

 exactly the same, and therefore it will be necessary to define this disease, for which we will adopt the 

 common and expressive name of Bitter Pit. 



SYMPTOMS. 



The symptoms of Bitter Pit are very decided. It is an internal disease affecting the flesh of the 

 apple, and the pits or depressions are caused by the skin shrinking or falling in. This falling-in 

 or pitting is due to the cells having collapsed underneath, so that the mechanical support and proper 

 nourishment of the skin at that particular spot is interfered with. The depressions are more or less 

 regular and circular, and the colour of the depressed skin may vary from a paler or deeper green to a 

 light brown. Beneath the skin the tissue corresponding to the depressions is brown in colour, relatively 

 dry, and spongy in texture. This browning of the tissue originates immediately beneath the skin, 

 but it may extend inwards along the course of the conducting vessels, and thus give the flesh a streaky 

 appearance. Internal browning of the pulp-cells may occur, however, without any external indication. 



Bitter Pit develops in the fruit, either on the tree or in storage, and usually when the apple is 

 approaching maturity, but never when fully mature. One always looks for its first indications around 

 the "eye," and the pitting is generally confined to the calyx end of the fruit. 



CONFLUENT PIT OR "CRINKLE." 



Although the isolated pits or saucer-shaped depressions are characteristic of the disease, this is 

 not the only form of it. Just as there are discrete and confluent forms of small-pox, so there are 

 discrete and confluent forms of Bitter Pit. In the latter case the surface of the apple towards the 

 "eye" end is thrown into wavy folds or large irregular depressions, giving it an unshapely or distorted 

 appearance. This confluent form is known in Australia under the name of "Crinkle," "Pig-face," or 

 "Monkey -face," and has the brown dry tissue beneath the intact skin, only it is run together into large 

 irregular masses instead of being in isolated patches. 



