DISEASES SUPERFICIALLY RESEMBLING BITTER PIT. 15 



the bags grew to the normal size, but deficient in colour, and out of the 136 Annie Elizabeth apples 

 75 were pitted and 61 clean, 5 of the pitted apples being also "crinkled" (Report I., Figs. 42, 43). 



It is absolutely certain, therefore, that Pit and "crinkle" are developed in the absence of insects, 

 and it remains to be seen how far the results of insect punctures agree with the genuine forms of Pit. 



The presumed effects of insect punctures on the apple fruit have been recently described in France 

 and America, and examples will be given of the piercing of fruit by insects actually observed in 

 Australia. 



AUSTRALIA. 



In Mr. French's Handbook of the Destructive Insects of Victoria, Part I., published in 1904, 

 there is a coloured illustration of the apple being punctured by the Harlequin Fruit Bug. Where the 

 insect has pierced the fruit there are decayed spots shown on the surface, and this decay also extends 

 beneath the skin. In the early stages of attack there was no distinct evidence of puncture, and 

 certainly there was no depression. But after a considerable time dark blotches appeared under the 

 skin, surrounding each particular spot where the puncture had been made. The beak of the insect 

 penetrated the skin of the fruit and extracted the juice, thereby causing the decayed spots. These 

 "spots" are irregular in outline, small, brown, and very slightly depressed. There is no risk of confusion 

 between the punctures of such insects and Bitter Pit, as may be seen from the faithful drawings made 

 by Mr. C. C. Brittlebank, Vegetable Pathologist, and here reproduced (Figs. 31-33). 



FRANCE. . 



In France the first reference to this disease was in 1901, when Professor Mangin referred to it as 

 "La Graisse ou Maladie des Taches des Pommes" (The Grease or Spot disease of the Apple). Then, 

 in 1908, Delacroix described it under the name of "Points brun de la chair des pommes" (Brown spots 

 of the flesh of the apple). Finally, in 1915, M. Bois (1), in the Bull. Soc. Nationfile d'Acclimntation 

 de France, gives the latest information concerning this disease under the name applied to it by Professor 

 Mangin. His brief description of the disease is as follows : "This name is given to an affection of 

 the apple, of which the causes are not yet absolutely certain, which depreciates considerably the fruits 

 of several varieties of apples classed among the very best, such as Reinette du Canada, Calvillc, etc. 

 The alteration is characterized by the small masses of spongy tissue, brownish, scattered beneath 

 the skin of the fruit and penetrating to a depth which may reach up to a centimetre. They correspond 

 generally to the spots which form upon the skin of the fruit small depressions of a greyish colour, 

 from 1 to 5 millimetres in diameter." 



As early as 1901 Professor Mangin (8), in a note appearing in the Revue Horticole, attributes the 

 disease to the punctures of insects, which had injected into the wound produced a liquid capable of 

 irritating and mortifying the tissues. 



This view is accepted by M. Bois as the correct one, and accordingly he recommends various 

 measures for the destruction of the insects, such as whitewashing, spraying, fumigation, etc. 



It is evident that the insect theory of the disease, like the poison theory, has been arrived at 

 without sufficient data to establish it as generally applicable. While insect punctures may produce 

 decayed "spots," there are depressed spots with the underlying diseased tissue which cannot be thus 

 accounted for. 



AMERICA. 



In America Charles Brooks and D. F. Fisher (2), of the United States Department of Agriculture, 

 have been recently investigating various "spot diseases" of the apple which might be confounded 

 with Bitter Pit, and refer specially in one article to "Jonathan Spot, Bitter Pit, and Stigmonose." 

 Another article, appearing in Better Fruit for February, 1916, bears the expressive title of "Spot 

 Diseases of the Apple causing much general confusion." 



