DISEASES OF CULTIVATED PLANTS 475 



hole fungus the fruit is of small value and the trees put forth new 

 foliage and blossoms, thus leaving immature wood and a sappy 

 condition for trouble in winter. Under such circumstances the sec- 

 ondary losses may be enormous. This fungus is readily prevented 

 by spraying with self-boiled lime sulfur, the first application being 

 made when the leaves are half grown, and two more at intervals of 

 about three weeks. (Ohio E. S. B. 121.) 



Other Plum Diseases. Yellows (See page 482) ; Crown Gall 

 (See page 451) ; Root Rots (See page 452). 



PEACH DISEASES. 



The Peach Blight. The fungus causing the so-called blight, or 

 shot-hole fungus, has been identified by us as Coryneum beyerinkii. 

 This has been mentioned frequently as doing damage in this coun- 

 try, though never to nearly so great an extent as in California. The 

 trouble consists in the dying of the buds on the fruiting wood, spot- 

 ting of the green twigs, and dropping or non-development of the 

 young leaves and fruit. Particularly noticeable, and the most 

 prominent feature of the disease, was a copious gumming, or exuda- 

 tion of masses of gelatinous sap from the twigs, originating in the 

 dead spots and buds. This gumming was extremely abundant in 

 wet weather all over the one-year-old fruiting twigs of affected trees, 

 and with the blighted leaves and fruit and spotted, leafless, dead or 

 dying twigs and shoots, gave the tree a most distressing and alarm- 

 ing appearance. The crop was entirely ruined in badly affected or- 

 chards and the trees brought into an extremely weakened condition. 



This describes, in a general way, the nature of this disease. It 

 is readily distinguished from any other peach trouble by the features 

 mentioned. It is essentially a winter or early spring disease of the 

 fruiting twigs, the one-year-old wood which is the valuable part of 

 the tree. This growth becomes killed all through the tree, except in 

 the very top, and very serious loss and injury result. Most of the 

 infection takes place in the winter, before the new growth starts, on 

 twigs which were healthy and free from the trouble at the end of the 

 growing season the previous fall. The new fruit becomes affected to 

 some extent, but the principal damage is done by the killing of the 

 buds and whole twigs at a period previous to the development of 

 fruit. 



Spraying in the latter part of October seemed effective, and from 

 then on to the middle or last of December the best results of one 

 application were secured in preventing blight infection. The at- 

 tacks of curl leaf complicated matters. In many cases a complete 

 blight control, obtained by early spraying, was nullified by un- 

 checked attacks of the other disease. Spraying in November and 

 December did not altogether hold the curl in check, while the 

 February and March applications did so perfectly. It therefore 

 seems best in the future to advise two sprayings, one early and one 

 late, to insure freedom from both diseases. 



Practically all these results refer to Bordeaux mixture. "We 

 have reason to feel sure that lime, salt, and sulfur spray would give 



