74 



BITTER PIT INVESTIGATION. 



cells. A mesh here and there will be left unfinished, and there the cells immediately adjoining will 

 not receive their regular supplies of nourishment through the regular channels, and collapse, and 

 death will ensue. It is the vascular network which controls the supplies, and if it fails to keep pace 

 with the growing cells, then at these particular spots where meshes of the net are wanting the groups 

 of cells dry up and die. 



But it is not only an excess of water which may cause Bitter Pit, for it is well known that it 

 may arise in a dry season, and shrinking and shrivelling of the cells may be due to drought. Instances 

 will be given of its occurrence in both a wet and a dry season, and how a deficiency of water may 

 cause it will now be explained. If the fruit was sufficiently nourished to approach maturity, and 

 the supplies then began to fail, more water being given off at the surface than taken in by the roots, 

 the outer portion of the flesh immediately beneath the skin would be the first to receive a check in 

 the diminished supply. Even although the net was completely formed, wherever the mesh of the 

 network of vessels failed in conducting water, there the adjoining cells would collapse, and the entire 

 patch shrivel and become brown. 



The prevailing opinion in Australia is that wet seasons combined with light crops favour 

 the disease, but if it happens that the rainfall is so equally distributed that the crop is 

 normal and regular, then there may be very little pitted fruit. Some, however, are equally 

 certain that dry weather favours it, and as we shall see it may be associated with either dry 

 or wet seasons, so long as they are intermittent in their character at the critical period of 

 growth. 



The apple tree would seem to thrive and grow luxuriantly with plenty of moisture, and it 

 is only when dry spells intervene between heavy showers that it suffers. Darwin, in his " Journal 

 of Researches," remarks about Valdivia : — " The town is situated on the low banks of the stream and 

 is so completely buried in a wood of apple trees that the streets are merely paths in an orchard. I 

 have never seen any country where apple trees appeared to thrive so well as in this damp part of 

 South America ; on the borders of the roads there were many young trees evidently self-grown. 

 In Chiloe the inhabitants possess a marvellously short method of making an orchard. At the lower 

 part of almost every branch, small conical, brown, wrinkled points project ; these are always ready 

 to change into roots, as may sometimes be seen where any mud has been accidently splashed against 

 the tree. A branch as thick as a man's thigh is chosen in the early spring, and is cut off just beneath 

 a group of these points ; all the smaller branches are lopped off, and it is then placed about 2 feet 

 deep in the ground. During the ensuing summer the stump throws out long shoots, and sometimes 

 even bears fruit. I was shown one which had produced as many as 23 apples, but this was thought 

 very unusual. In the third season the stump is changed (as I have myself seen) into a well-wooded 

 tree, loaded with fruit." 



If we consider the conditions prevailing in other countries in a season when this disease is 

 very injurious, it is found that they are most varied. The weather conditions play an important 

 part, and, while in England during the past season the weather was so exceptional that it brought 

 forth a lengthened correspondence in Nature and other scientific journals, the disease was at the 

 same time extremely prevalent. The weather experienced during the summer and first half of the 

 autumn of 1911 was exceptionally hot and dry, and there was a persistent, parching drought. Dry 

 conditions are not always supposed to be associated with the prevalence of Bitter Pit, and, in order 

 to get at the facts of the case as fully as possible, I made certain inquiries, as the following 

 correspondence will show: — "In the issue of The Garden for 2nd December, 1911, I notice some 

 observations by ' Scientist ' on Bitter Pit in apples, and, as I am investigating this particular disease 

 at present, I would be pleased to have further information on one or two points. He observes that 

 the disease was extremely prevalent during the past year, and, since the past summer in England 

 was exceptionally hot and dry, it would be interesting to know the rainfall during the maturing of 

 the fruit in the orchard where the fruit of Tower of Glammis that was illustrated was grown. 



