Like peach yellows this disease is confined to the northeastern United States. It has been known for but a few years in this country. The origin of little peach is unknown, but the suggestion has been made that it came from abroad with Japanese plums. The first appearance of the disease in America was once believed to have been in Michigan prior to 1893, but there are some indications now that it appeared in New York State at an earlier date. More recently important notices of little peach have come from New Jersey and from Ontario, Canada.
This disease is not confined to trees of any particular age, although a larger number of the cases are found on trees over five years of age. In New York State the Smock and Salway varieties remained apparently resistant for several years, but finally these have become affected. In some localities of the states of New Jersey and Michigan little peach is a more destructive disease than peach yellows.
Little peach may or may not appear on a tree at the same time as yellows. In the former case the two diseases are often considered together. Little peach is more difficult to detect than yellows. In the case of yellows the. premature ripening of the fruit, the internal red splashes, and the slender shoots with narrow leaves are easy marks of distinction. But in little peach, foliage characters are the most prominent earmarks of the disease, hence a knowledge of varietal characteristics of the foliage is necessary in detecting the presence of this trouble. For example, the Elberta has a long, wide, straight leaf with a u drooping inclination, while the Crawford has a short, wide, crescent - shaped leaf which stands at right angles to the twig.
The first evidences of little peach appear comparatively late in the growing season. It is still evident late in September. The fruit, instead of ripening prematurely as in the case of yellows, remains small and ripens about ten days later than is normal for the variety. The flavor of affected fruit is inferior, although the color may be as desirable as in healthy fruit. The flesh is characterized as stringy, especially in the case of early clingstone varieties. The pits of such fruits are smaller and shriveled, and almost invariably fail to sprout. Leaves on affected trees exhibit a light or yellowish green color, and those at the base and through the center of the tree show a rolled and drooped aspect. In severe cases all leaves on a tree show this symptom. This calls to mind certain stages of the yellows with which the little peach disease may be confused, and unless the tree is bearing fruit at the time of the diagnosis it is difficult to determine which disease is present. However, the distinction between the two troubles is of no practical importance, and neither yellows nor little peach is likely to be confused with other diseases. It is difficult to detect little peach in young trees, but a possible character has been suggested, namely, a decided erect growth of numerous short twigs. Affected trees usually die within three or four years after infection.
Summarizing the prominent symptoms of little peach, the following should be noted: the fruit remains small, about one-half or one - third its usual diameter, it ripens about ten days later than normal fruit, and possesses a bitter flavor and a stringy flesh; the leaves are small, light to yellowish green, and droop or incurve to some extent.
This phase of little peach has been the subject of no little investigation, but practically no progress has been made. The cause is not known, but it is supposed that the factor here involved is closely allied to that of peach yellows (see page 286), but that the two diseases are distinct and entirely independent of each other. The disease is contagious; the causal factor can be carried by budding, although the disease may not come into evidence until the second year after inoculation in this fashion.
So far as known, diseased trees have never been cured. Spraying, watering, mulching and fertilizing have been of no avail. The removal of diseased parts is not effective, as it is in the case of fire blight of pears and similar diseases.. The only remedy known is the removal and burning of diseased trees. To delay this operation only means added loss. This procedure, if pursued persistently, if all affected trees are systematically marked and destroyed at the proper time, will yield satisfactory results. The best orchard practice should be employed; favorable sites should be selected, only trees from reliable nurseries should be planted, reasonable cultivation, fertilization, spraying and pruning should be done. Observe the behavior of all trees and remove suspicious ones. Nurserymen should use care in bud - selection, taking every precaution against the disease.
Atwood, G. G. Peach yellows and little peach. New York State Agr. Dept. Bul. 61: 1721 - 1742. 1914.
Blake, M. A. Peach yellows and little peach. New Jersey Agr. Exp. Sta. Bul. 226: 3 - 26. 1910.
Taft, L. R. Spraying calendar for 1898. Little peach. Michigan Agr. Exp. Sta. Bul. 155: 303 - 304. 1898.
Smith, E. F. Notes on the Michigan disease known as "little peach." Fennville (Mich.) Herald. Oct. 15, 1898.
Caesar, L. Peach diseases. Peach yellows and little peach. Ontario Agr. Dept. Bul. 201: 43 - 59. 1912.
Stevens, F. L.: and Hall, J. G. Little peach. In Diseases of Economic Plants, p. 139. 1910.