200 PEACH LEAF CUKL: ITS NATUEE AND TREATMENT. 



The preceding records, showing the comparative susceptibility to curl 

 of nearly 200 varieties of peaches, will enable the grower who contem- 

 plates setting an orchard to make his choice of varieties advisedly. 

 As already said, however, many superior varieties are very subject to 

 curl, hence the practical methods of preventing it as detailed in this bul- 

 letin make it possible to successfully grow the most susceptible varie- 

 ties in the most unfavorable situations, so far as this disease is concerned. 

 Such varieties are in fact saved to the peach industry of lai'ge sections 

 of the country b}^ means of this preventive treatment. The Elberta, 

 a favorite in both the East and the West, and the Lovell, a favorite in 

 California, may now be cultivated to any desired extent in regions 

 from which they have heretofore been practically excluded by curl- 

 advantages that are certainly not the least of those arising from the 

 recent work in the treatment of that disease. 



As a striking illustration of what has just been said, the following, 

 contained in a letter recently received by the writer from a gentleman 

 in northern California, is given: He states that the Lovell variety 

 will curl in his locality so as to be of little use, if not spraj^ed. One of 

 his neighljors, who had a small orchard of that variet}^, stated that he 

 intended grafting the trees to some other peach, as they did so badl}^ 

 on account of curl, but our correspondent advised the winter use of 

 Bordeaux mixture, cautioning the grower to spray his trees thor- 

 oughly. This was done, and the trees bore a fine crop of fruit. The 

 work was so satisfactory that instead of grafting over the Lovell 

 variety a block of Fosters was grafted to the Lovell, the variet}^ with 

 which the detailed experiments of the writer were conducted in the 

 Sacramento Valley in 1894: and 1895. 



TREATMENT OF NURSERY STOCK. 



The nurseiy is not onl}" the source of the orchard, but also very 

 largely the source of orchard diseases, and its health is . therefore of 

 common interest to the orchardist and nurseryman. Could a nursery 

 be freed from curl, many orchards planted from it would not suffer 

 from the disease for years, especiall}^ if isolated. There is little doubt 

 that curl has been largely disseminated throughout the world by 

 means of nursery trees. 



It has been supposed that the main source of spring infection of 

 trees was from the perennial mycelium already in the buds, and were 

 this hj'pothesis true nurserymen could scarcely hope to procure buds 

 for their seedlings which were free from this disease. The spray 

 work upon curl has shown, however, that the single external applica- 

 tion of a fungicide is sufficient to prevent 96 to 98 per cent of curl 

 when the treatment has been thoroughly made. This appears to 

 indorse the view that at least 98 per cent of the spring infections are, 

 as elsewhere claimed in this bulletin, from spores upon the tree, prob- 

 ably largely resting upon or within, the bud scales themselves. 



