BITTER- PIT OF THE APPLE. 



By I. B. Pole Evans, B.A., B.Sc, F.L.S., Plant Pathologist. 



Introduction. 



In February, 1906, my attention was drawn by Mr. C. P. Lounsbury, 

 the Government Entomologist, Cape Colony, to a pecuUar spotting in 

 Cape apples. The trouble was known locally simply by the name of 

 " bitter-pit," and as it is now so commonly recognised under this name 

 I do not propose in this report to substitute any other, although there 

 are certain objections to the term here employed. 



In the following month, Mr. Lounsbury conducted me over the 

 orchards of the Cape Orchard Company at Hex River, where the spotting 

 was very evident both on the fruit on the trees and also on the apples 

 which were in cold storage. 



The prevalent theory in vogue regarding the trouble at the time was 

 that it was due to a mechanical injury brought about by blown sand. A 

 number of varieties of affected apples were then collected for micro- 

 scopic examination, and as the disease was one of such general importance, 

 arrangements were made with the Cape Department of Agriculture that 

 I should devote as much time as I could spare to an investigation of this 

 trouble. The Cape Orchard Company also very kindly undertook to place 

 the necessary faciUties, in the shape of conducting experiments at their 

 orchards, at my disposal. 



An exhaustive histological and bacteriological examination of these 

 spots was first carried out, but neither revealed any evidence of fungi 

 or bacteria. In the histological part of the enquiry, however, a great 

 abundance of starch in the diseassd areas at o,iC3 suggested that the 

 action of diastase must be inhibited in some way or other, and that 

 possibly some chemical constituent might be lacking which was necessary 

 for the complete conversion of the starch into sugar. At this stage, Mr. 

 Herbert Ingle, late Chief Chemist to this Department, became much 

 interested in the problem, and kindly offered to assist me in the investi- 

 gation by making analyses of soil, healthy and diseased apples, etc. 



It was then arranged that we should pubhsh a joint report on this 

 subject, but, unfortunately, owing to unforeseen circumstances, Mr. Ingle 

 left South Africa before he was in a position to publish his results, and 

 it has therefore been deemed advisable in the interests of the fruit-growing- 

 community to delay no longer the present conclusions, which are merely 

 put forward with a view to suggesting certain hnes upon which apple 

 growers in this country should work in order to minimise their losses 

 through this trouble. 



