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(2.) The orchard losses from peach leaf-curl vary from a small amount of 

 fruit to the entire crop, while in many instances young trees are killed. The 

 national losses from this disease will amount to $3,000,000 annually. 



(3.) Curl is caused by a parasitic fungus known as Exoascus deformans, 

 the ravages of which are largely dependent upon the atmospheric conditions 

 prevailing while the trees are leafing out. Rains and cold weather at that 

 time tend to increase the severity of the trouble by favouring the growth of 

 the parasite and interfering with the proper functions of the host. For these 

 reasons orchards near large bodies of water and in low or damp situations are 

 aiore subject to curl than those in dry regions or in elevated situations. 



(4.) Most of the spring infections of peach leaves are due to the spores of 

 the fungus and not to a perennial mycelium, as formerly held, hence the 

 efficacy of sprays. 



(5.) Curl was first successfully treated in California during the period from 

 1880 to 1885, the success depending upon the application of fungicides to the 

 dormant trees. The disease was not successfully treated in Europe for ten 

 years after its prevention in the United States. 



(6.) The copper sprays are now found to be more effective than the sulphur 

 or other sprays first used. Of the various sprays experimented with, Bordeaux 

 mixture, in the proportion of 5 pounds copper sulphate, 5 pounds lime, and 

 45 gallons of water, gave the best results, the equal weights of the copper 

 sulphate and lime being most effective when the mixture is applied shortly 

 before the opening of the blossom buds. When it is desired to increase the 

 durability of a spray by increasing the proportion of lime, the application 

 should be made earlier or equal proportions of copper and lime should be 

 maintained. l"he total saving of foliage increases with the increase of copper 

 sulphate when the amount of lime remains constant, but the average saving 

 per pound of copper sulphate decreases with the increase of copper used. 



(7.) In the treatment of peach leaf-curl, from 95 to 98 per cent, of the 

 spring foliage was saved by spraying. A net gain of 600 per cent, in foliage 

 over that retained by adjoining unsprayed trees resulted in the case of several 

 different sprays. Bordeaux mixture when applied to the dormant tree 

 increased the weight and starch-producing power of the leaves, and the 

 sprayed trees showed a great gain over the unsprayed in the number and 

 quality of the fruit buds they produced for che following year, the gain in the 

 number of spur buds being over 100 per cent, in some cases. The lower 

 'limbs of sprayed trees showed a marked gain over those of unsprayed trees 

 .as compared with the upper limbs in both the number of fruit btids and 

 lateral shoots they produced. 



(8.) The average value of the fruit per tree in rows treated with the most 

 effective Bordeaux mixture ranged as high as $6.20 above that per tree in 

 .adjoining untreated rows, or the equivalent of a net gain of $427.80 per acre 

 where trees are planted 25 by 25 feet. Over 1,000 per cent, net gain in the 

 ,fruit set has resulted in the use of some of the more effective sprays. 



(9.) The trees should be sprayed each season, as the experiments proved 

 that treatment one season will not prevent the disease the following year. 

 Spraying should also be done even though the trees may not be expected to 

 bear, as the loss of the crop of leaves is shown to result in as great a drain 

 upon the trees as does the maturing of one-half to two-thirds of a crop of fruit. 



(10.) The work demonstrates that peach leaf -curl may be cheaply and 

 easily prevented in California, in western Oregon and Washington, and along 

 'the east shore of Lake Michigan, where curl causes great loss, as well as in 

 : all other peach-growing sections of the United States. 



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