PEACH LEAF CURL. 



Next to the apple, the peach is the fruit of the greatest commercial 

 importance in the State of Xew York. It is grown most successfully 

 near large bodies of water, such as the Great Lake Regions of Western 

 New York. It is also extensively grown in some parts of the Hudson 

 River Valley. It is very susceptible to injury induced by extremes of 

 temperature, and is therefore especially favored by the tempering 

 influences of bodies of water. In some seasons, however, in these locali- 

 ties weather conditions are such as to favor the development of fungous 

 diseases, not the least destructive of which is the Leaf Curl. 



The natural host plant for the fungus causing this disease is not 

 certainly known. Certain it is, however, that at present the peach is 

 everywhere the plant most commonly attacked. According to Pierce 

 ('oo) this malady " is confined almost wholly to the peach or its 

 derivatives, as the nectarine and peach-almond." He further states that 

 the disease has been noted on plum and almond but says this is rare. 



THE DISEASE 



Origin, history and geographical distribution. — As Duggar ('09) has 

 pointed out, " Attempts to determine the country which might be 

 regarded as the original home of this fungus have proved wholly futile. 

 Leaf Curl is now a more or less common disease in nearly all peach- 

 growing regions of the world. In North America it is known through- 

 out the country, at least east and west, and from northern Canada to 

 the Gulf of Mexico; while in South America it has also been reported 

 from several peach-growing districts. In Europe it has long been com- 

 mon, having been reported in England as early as 182 1, and it is dis- 

 astrous in many sections of China and Japan. This disease occurs also 

 in southern Africa, and from the Sahara northward in Algeria. Accord- 

 ing to reports it prevailed in Australia even in 1856, and it has proved 

 most pernicious to peach-growing interests in New Zealand. In general, 

 therefore, this disease is known wherever peach-growing is practiced. 

 In the United States the general regions in which the more serious and 

 constant injuries have been felt are apparently two, viz., the region of 

 the Great Lakes and the Pacific Slope region, the latter including also 

 districts in central and northern California." 



•00. Pierce. N. B., I'cach Leaf Curl; Us \ature and Treatment, U. S. D. A. 

 Div. Veg. Phys. and I'ath., Bui. 20:18, 1900. 



'09. Duggar, B. M., Fungous Diseases of Plants, Ginn & Co. \. Y., 1909:176 

 and 177. 



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