JOIMAL OF AGffiETlML RESEARCH 



Vol. XVI Washington, D. C, February 24, 1919 No. 8 



APPLE-SCALD 



By Charles Brooks, Pathologist, and J. S. Cooley and D. F. Fisher, Assistant 

 Pathologists, Fruit-Disease Investigations, Bureau of Plant Industry, United States 

 Department of Agriculture 



INTRODUCTION 



The present paper gives a report of studies on the nature and control 

 of apple-scald, including experiments upon the relation of orchard and 

 storage conditions to the development of the disease. The literature 

 upon the subject of apple-scald and the apparatus ^ and methods ^ used 

 in these experiments have been rather fully reported in earlier publica- 

 tions, 



RELATION OF CHARACTER OF FRUIT TO SCALD DEVELOPMENT 



MATURITY 



It is generally recognized that immature apples (Malus sylvestris) 

 scald worse than mature ones.^ A striking example of the fact was 

 obtained in storage experiments at Wenatchee, Wash., in the winter of 

 1 91 7-1 8. The apples of the different pickings were from the same trees 

 and were approximately alike in every respect except in maturity. 

 The first picking of the various varieties was made when the ground 

 color of the fruit was very green and when the red varieties had de- 

 veloped bHt a slight blush, the second picking when the ground color 

 was beginning to show yellow and most of the apples of the red varieties 

 had become deeply colored. The apples were stored in commercial box 

 packages. One or more boxes of fruit were used under each storage 

 condition of every experiment. The final notes for the Rome Beauty 

 and Stayman Winesap were taken on March 19 and for the other varieties 

 on Match 12. The Rome Beauty and Stayman Winesap were allowed 

 to stand in cellar storage five days before the notes were taken, and the 

 other varieties were held in a laboratory at 20° C. for four days before 

 note taking. The results are given in Table I. 



In all cases there was less scald on the well-colored than on the poorly 

 colored fruit, and in most cases fruit picked at the proper maturity was 

 almost entirely free from scald. 



' Brooks, Charles, and Coolev, J. S. temperature relations of apple-rot fungi. In Jour. Agr. 

 Research, v. 8, no. 4, p. 139-164, 25 fig., 3 pi. 1917. 



* EFFECT OF TEMPERATURE, AERATION, AND HUMmiTY ON JONATHAN-SPOT AND SCALD 



OF APPLES IN STORAGE. In JouT. Agr. Research, v. 11, no. 7, p. 287-318, 23 fig., pi. 32-33, 1917. Literature 

 0> cited, p. 316-317. 



' Ramsay, H. J., McKay, A. W., Markell, E. L., and Bird, H. S. the handling and storage oP 

 APPLES in the pacific northwest. U. S. Dept. Agr. Bui. 587, 32 p., 7 col. pi. 1917. 



CD 



Journal of Agricultural Research, Vol. XVI, No. 8 



■■ * Washington, D. C. Feb. 24, 1919. 



rv '*^ Key No. G-173 



Q_ (195) 



