UNITED STATES DEPARTMENT OF AGRICULTURE 



MISCELLANEOUS PUBLICATION No. 168 



WASHINGTON, D.C. 



Issued November 1933 



MARKET DISEASES OF FRUITS AND VEGETABLES 

 APPLES, PEARS, QUINCES' 



By Dean H. Rose, senior physiologist, Chaeles Brooks, principal pathologist, 

 D. F. FiSHEE, principal horticulturist, and C. O. Bratley, associate patholo- 

 gist, Division of Fruit and Vegetable Crops and Diseases, Bureau of Plant 

 Industry 



Page 



Introduction... 2 



Apples 4 



Alternaria rot 4 



Ammonia injury 5 



Apple-cedar rust 5 



Apple-maggot injury 5 



Bitter pit 7 



Bitter rot 8 



Black rot 10 



Blotch 11 



Blue-mold rot 12 



Boxwood scald 14 



Brown rot 14 



Bruises 15 



Bullseye rots 17 



Chemical injuries 19 



Codling-moth injury 21 



Core rot 22 



Cork 23 



Drought spot 24 



Flyspeck 24 



Freezing injury 24 



Fruit spot 29 



Gray-mold rot 30 



Hail injury 31 



Heat injury 31 



Honeydew 32 



Internal breakdown 32 



Internal browning 33 



Jonathan spot 34 



CONTENTS 



Apples— Continued -^^S® 



King David spot.. 34 



Leaf-hopper specking 35 



Leaf -roller and green fruit- 

 worm injury 35 



Miscellaneous rots 35 



Pansy-spot injury 36 



Pear-leaf blister-mite in- 

 jury 36 



Phytophthora rot 36 



Pink-mold rot 37 



Powdery mildew 38 



Plum-cur culio injury 39 



Red spots 40 



Rhizopus rot 40 



S an Jose scale injury 40 



Scab 41 



Scald 43 



Soft scald 44 



S oggy breakdown 45 



Sooty blotch 45 



Spongy dry rot 46 



Spray injury 46 



Stigmonose 47 



Sunburn and sun scald. . 48 



Water core 49 



Pears 49 



Ammonia injury 49 



Black end 50 



Black rot 51 



Pears— Continued ^^se 



Black spot 51 



Blue-mold rot 51 



Brown rot 51 



Bruising 51 



Core breakdown 51 



Freezing injury 52 



Gray-mold rot 52 



Pear-leaf blister-mite in- 

 jury 53 



Pear-psyUa injury 54 



Pink-mold rot 54 



Powdery mildew 54 



Rhizopus rot 54 



San Jose scale injury 54 



Scab 54 



Scald 55 



SiUcate injury 55 



Smothering injury 56 



Sooty blotch 57 



Spray injury 57 



Stigmonose 57 



Quinces 57 



Black rot 57 



Black spot 57 



Blue-mold rot 58 



Brown rot 58 



Oriental fruit-moth in- 

 jury £8 



Literature cited 59 



1 This publication is the third in a series designed to aid in the recognition and 

 identification of pathological conditions of economic importance affecting fruits and 

 vegetables in the channels of marketing, with the view of facilitating the market inspec- 

 tion of these food products and preventing losses from such conditions. It represents an 

 extended revision and elaboration, with the addition of numerous colored illustrations, of 

 a preliminary (multigraphed) Handbook of Diseases of Fruits under Market, Storage, and 

 Transit Conditions, prepared in 1919 by Dean H. Rose and the late O. F. Burger for the 

 use of the food-products inspectors of the Bureau of Agricultural Economics. The ma- 

 terial is organized on the basis of the botanical families to which the plants belong, but 

 no botanical system is followed in arranging these families. Practical considerations 

 make it desirable to issue the material in separate sections arranged somewhat in the 

 order of the economic importance of the crops. The Host Index of the Fungi of North 

 America, by A. B. Seymour, 1929, is used in the main as a guide to the nomenclature of 

 causal fungi and the names of authorities therefor. The common names of the insects 

 mentioned are those approved for general use by the American Association of Economic 

 Entomologists (Jour. Econ. Ent. 24; 1273-1310, 1928). 



The statements regarding fruit injuries caused by insects are made with the approval 

 of the Bureau of Entomology. B. A. Porter, of that Bureau, has collaborated with the 

 authors in the preparation of the entomological portions of the bulletin. The colored 

 plates are reproduced from water-color paintings made by L. C. C. Krieger, R. C. Stead- 

 man, J. Marion Shull, and Mary D. Arnold, of the Bureau of Plant Industry, under the 

 direction of Dean H. Rose, Charles Brooks, and D. F. Fisher, and from colored photo- 

 graphs prepared through the collaboration of Webster Bros., Chicago, 111., under the 

 direction of Dean H. Rose and the late O. F. Burger. 



181541°— 33 1 1 



