No disease gives the commercial plum-grower so much trouble as Brown Rot. It occurs more or less every year, affects the ripe or ripening fruit, and destroys it absolutely (Fig. 99). It is equally annoying and destructive in small home gardens, rotting the fruit just at the time when it is ready for use.

It is said that thin-skinned varieties are more resistant to Brown Rot than others. It is also said that the Triflora, Americana and Japanese groups are more injured than plums in other groups. The Burbank, Abundance and Satsuma are said to be most susceptible, while several varieties are listed as resistant. Among the latter may be noted: Hansom, Clinton, Forest Rose, Indiana, Miner, Nebraska, Prairie Flower and others. It is to be noted that most of the list of so - called resistant plums are varieties of minor importance; at least they are not leading American plums. And it is doubtful whether the Burbank, Satsuma and others suffer a great deal more than other prominent varieties. Careful observations along this line seem desirable.

Brown Rot of plum is a disease also found on the peach and cherry (see pages 270 and 170, respectively). On these last two fruits the disease is perhaps more destructive than on plums. The common occurrence of the disease on all these hosts gives it a wide range over this and other countries. Losses in various parts of the United States are estimated at 30 to 100 per cent on susceptible plums. At times twig blight is caused by the fungus (Sclerotinia cinerea); this type of injury has been reported from Iowa and New York. The Red June, Wickson and other upright-growing varieties are peculiarly susceptible to the twig blight form of this disease. In the Pacific Northwest blossom blight and mold in transit are important phases of Brown Rot on prunes.

A more complete discussion is given under Peach, page 270.

References

Hesler, Lex R. Diseases of the plum. Brown rot. In The Fruit Industry in New York State. New York Agr. Dept. Bul. 79: . 1192 - 1195. 1916.

Brooks, Charles, and Fisher, D. F. Brown rot of prunes and cherries in the Pacific Northwest. U. S. Agr. Dept. Bul. 368: 1 - 10. 1916.

Stewart, F. C. Notes on New York plant diseases, I. Plum. Twig blight and canker, Sclerotinia fructigena (Pers.) Schrt. New York (Geneva) Agr. Exp. Sta. Bul. 328: 381 - 383. 1910.

Fig. 99.   Group of plums mummified by the Brown Rot fungus.

Fig. 99. - Group of plums mummified by the Brown Rot fungus.

Jones, L. R. The brown rot of plums. Vermont Agr. Exp. Sta.

Rept. 5: 134-135. 1892. Bailey, F. D. Experimental spraying of prunes for control of brown rot. Oregon Crop Pest and Hort. Bienn. Rept. 1913-1914: 241244. 1915. Jackson, H. S. Prune brown rot on dried fruit. Oregon Crop Pest and Hort. Bienn. Rept. 1913-1914: 276 - 277. 1915. Valleau, W. D. Varietal resistance of plums to brown rot. Journ.

Agr. Research, 5: 365-396. 1915. (See additional references to literature on Brown Rot under Peach, page 276, and under Cherry, page 172.)