116 



BITTER PIT INVESTIGATION. 



82. Smith, R. E., and Smith, E. H. California Plant Diseases. California Agr. Exp. Sta., Berkeley. Bull. 218, pp. 1092 



and 1093. June, 1911. 



Fruit spot of apple is described and illustrated, and is said to be similar to " brown spot " or " Baldwin spot." 

 " No cause or remedy satisfactorily demonstrated in California." " Hollow Apple " or Crinkle is also 

 figured. 



83. Sorauer, P. Schutz der Obstbaume gegen Krankheiten — das Stippigwerden der Aepfel, p. 80. Stuttgart, 1900. 



Cavities occur in the diseased tissue produced by the rupturing of the cells during the process of swelling, and 

 this, taken in conjunction with the presence of starch, while it is absent from the surrounding healthy 

 tissue, shows that the disease began before maturity was reached. 



g4. <: Stippigwerden " der Aepfel. Atlas der Pflanzenkrankheiten, Plate XXXIV. Berlin. 



The disease was supposed to be of a parasitic nature, but the parasite unknown. 



g5. Die Stippflecke. Handbuch der Pflanzenkrankheiten, p. 166. 1909. 



Most common in loose soils in dry seasons and the firm-fleshed varieties least susceptible. Owing to premature 

 dryness of the soil the necessary quantity of organic material is prevented from reaching the developing 

 fruit, so that certain groups of cells are starved and quickly perish. 



86. Sorauer, P., and Hollrttng, M. Stippigfieckigkeit der Aepfel. Zwdlfter Jahresbericht des Sonderausschusses fur 



Pflanzenschutz, p. 133. 1902. 



The distribution of the disease in various districts of Germany is given, and the injury is said to be greater 

 than that caused by Fusicladium. 



87. Southern Grower. Bitter Pit or Fruit Spot. Gardeners' Chronicle, L., p. 353. November 18, 1911. 



States that apples affected with "Bitter Pit" were noticed at the recent fruit show of the Royal Horticultural 

 Society in several of the prize lots. 



88. Stewart, F. C. Notes on various Plant Diseases — Baldwin Fruit Spot. New York State Sta. Bull. 164. 1899. 



Not caused by fungi or bacteria, and real cause unknown. 



„ i s the Baldwin Fruit Spot caused by Fungi or Bacteria ? New York Agricultural Experiment Station, Geneva. 



Bull. 104, p. 215. December, 1899. 



" Microscopic examination of the affected tissue revealed no fungus hyphse and no bacteria which could be 

 defi ritely demonstrated as such." 



90. Stewart, F. C. ; Rolfs, F. M. ; and Hall, T. H.~ Fruit Spot. New York Agricultural Experiment Station, Geneva. 



Bull. 191. December, 1900. 



Varieties specially liable to the disease are— Baldwin, Northern Spy, and Rhode Island Greening. The general 

 opinion is expressed that large specimens are more affected than small ones of the same variety. 



91. Stewart, F. C. Plant Diseases— Apple. New York Agr. Exp. Sta. Twenty-sixth Annual Report, p. 123. 1908. 



Neither fungi nor bacteria are concerned in this trouble. 



92. Taschenberg, E. L. Schutz der Obstbaume— -Das Stippichwerden der Aepfel, p. 112. Stuttgart, 1879. 



He refers to Jaeger, who in 1869 considered the cause of Bitter Pit to be bringing early maturing fruit too soon 

 into the celfar, whereas it should be kept for a considerable time in a dry room. 



93. Tidswell, F. (and others). Report of the Government Bureau of Microbiology for 1909, p. 53. Government Printer, 



Sydney, 1910. 



" Bitter Pit also received considerable attention, but no causative organism could be found." 



94. Whetzel, H. H. Baldwin Spot or Stippin. Proceedings, New York Fruit-growers' Association, January, 1912. 



A summary is given of the leading features of this disease, and under the heading of control it is stated — " It 

 is thus evident that those practices which most tend to a uniform normal growth throughout the season, 

 with fewest sudden stimulations or checks on growth, are most apt to afford least losses year in and year 

 out from the Stippin or Baldwin Fruit Pit." 



95. White, Jean. Bitter Pit in Apples. Proceedings, Royal Society, Victoria, XXIV. (N.S.), Pt. I. 1911. 



" The results of my observations, and of the experiments performed, without one single exception so far, seem 

 to indicate that the complaint popularly known as Bitter Pit is, strictly speaking, not a disease at all, but 

 rather a symptom of slow local poisoning, and that in the cases actually examined so far it appears to 

 be due to the poisonous compounds sprayed on to the surface of the fruits for the eradication of pests, 

 more especially insect pests." 



q 6> Bitter Pit and the Enzymes of the Apple. Journal, Department of Agriculture, Victoria, VIII., p. 805. 1910. 



The investigation was not fully completed, but the somewhat imperfect data seemed to show that the enzymes 

 persisted in the diseased cells for a short time after the death of the cells. 



97. Wortmann, J. Ueber die sogen. " Stippen " der Aepfel. Landw. Jahrb., XXI., p. 663. 1892. 



The theory brought forward as to its cause is, that concentration of the sap, following the loss of water by 

 transpiration, occurs in the pulp cells adjoining the vessels, and the acidity of the concentrated sap is 

 the direct cause of the injury. 



98. Z9CHOKKE, A. Stippigwerden der Aepfel. Landw. Jahrb. d. Schweiz, II., p. 192. 1897. 



Agrees with Wortmann that the disease is directly or indirectly related to the transpiration, and considers that 

 the unequal conduction of water in the fruit-flesh is one of the most important factors. 



