PEACH 



PEACH 



2499 



growth commonly prevents any serious check to the 

 trees. 



Various beetles and grasshoppers may cause some 

 damage at times by feeding upon the peach, such 

 injuries being most common in orchards in which grass 

 or weeds are allowed to grow freely. 



Diseases. 



The peach is subject to the attacks of a considerable 

 number of diseases. The most difficult to combat are 

 yellows, little-peach, and rosette. The causes of these 

 diseases are still unknown. Some suggest the presence 

 of a fungus, others an organism too small to be detected 

 by the ordinary microscope, and there is also the possi- 

 bility of enzymes. 



The advanced stages of yellows are indicated by a 

 prematuring of the fruit from a few days to at least 

 two weeks in advance of the normal season. Such fruit 

 is commonly red-spotted and blotched in its coloring 

 and may be insipid or bitter in flavor. Affected trees 

 may also develop sickly wiry twig-growths on the 

 trunks and branches. 



Little-peach is indicated by a characteristic drooping 

 of the foliage and by the fact that the fruit is smaller 

 and matures later than the fruit on healthy trees. 



Rosette occurs only in southern districts and is 

 readily distinguished by the tufts of leaf-development. 

 This disease is fatal within twelve months in many 

 instances. 



It is not known whether these diseases are entirely dis- 

 tinct or not, but they have been so regarded. Yellows and 

 little-peach attack all varieties in about the same pro- 

 portion. Infection does not appearto take place through 

 the soil, flowers, or seed. These diseases can readily be 

 transmitted to healthy trees or stocks, however, by bud- 

 ding. Buds taken from the apparently healthy parts of 

 diseased trees have invariably reproduced the diseases. 



The recognition of early stages of yellows and little- 

 peach have shown that these diseases are too frequently 

 distributed in nursery stock. It is now known that a 

 tree may be infected with either of these diseases for 

 three or four years without showing any prominent 

 symptoms. When good growing conditions are pro- 

 vided, the true state of affairs may be masked for a 

 time, but a check to growth will result in the prompt 

 appearance of the advanced stages of disease. 



Many cases of so-called "cures" of yellows have been 

 announced, but all have been without sound basis. Too 

 often trees affected with borers, winter injury and other 

 troubles are considered to be affected with yellows. 

 Diseased trees should be destroyed as soon as detected. 

 When such trees are left in an orchard, the disease 

 spreads to surrounding trees until all are affected. If 

 all diseased trees were destroyed annually in any dis- 

 trict and no diseased nursery trees were introduced, the 

 annual loss could readily be kept as low as 1 per cent, 

 without much doubt. Yellows attacks Japanese plums 

 as well as peaches, and this should not be overlooked 

 in control work. 



Peach leaf-curl, brown-rot, peach-scab and mildew 

 are fungous diseases of the; peach which cause much 

 damage annually. The leaf-curl attacks the foliage in 

 early spring just as the leaf-buds open, and the leaves 

 become curled, thickened, and distorted. The tips of 

 shoots may also become affected and the disease is 

 occasionally seen upon the fruit in a fan-shaped dis- 

 colored area. The affected leaves finally turn brown, 

 and fall from the trees in early summer. In severe 

 attacks, the trees are almost completely defoliated, 

 greatly reducing their vigor and causing them to lose 

 most of the fruit which may have set. This disease 

 is readily controlled by a spraying with lime-sulfur, as 

 directed for the scale, before the leaf-buds begin to 

 make growth. After the leaf -buds begin to expand, 

 however, the spraying may not prove effective. Recent 

 experiments have been tried with apparent success in 



New York of fall spraying for leaf-curl, as late as the 

 first part of December. 



Brown-rot was formerly one of the dreads of the 

 peach-grower. Thousands of baskets of fruit fre- 

 quently rotted on the trees just at harvest time. Not 

 until the value and safety of self-boiled lime-sulfur 

 summer spray was demonstrated by Scott were the 

 peach-growers supplied with an effective remedy for 

 the disease. This affliction may not only cause a rapid 

 decay of the fruit at ripening time, but it sometimes 

 attacks the blossoms and causes their death. The 

 affected blooms are distinguished from frost injuries 

 from the fact that they cling to the twigs, and gum 

 commonly oozes out from the canker formed upon the 

 twig at the base of the bloom. The small green fruits 

 may also decay at all stages, and the twigs may be 

 killed outright from numerous cankers upon the bark. 

 Such varieties as Triumph and Connecticut frequently 

 begin to rot before they ripen, and the entire crop may 

 be lost even when well sprayed. Such sorts should 

 never be planted. Varieties as susceptible as Champion 

 are not very satisfactory shipping varieties. A thor- 

 ough system of summer spraying, as outlined under 

 "spraying" (page 2500), should control brown-rot. 



Peach-scab is a fungous disease which appears upon 

 the fruits in the form of small black dots. In severe 

 cases these dots may be so numerous as to form a 

 sooty blotch. The skin of the fruit may then crack, 

 offering an excellent opportunity for brown-rot to 

 begin its destruction. Peach-scab is most serious from 

 central New Jersey south to Georgia. Upon hilly areas, 

 north of central New Jersey, it is rather uncommon 



2799. The three leaves at a joint, where fruit-buds are forming. 

 Fruit-buds sometimes form in the axil of single leaves, and 

 sometimes on short spurs. 



and it seldom requires any attention. The disease occurs 

 only upon the upper surface and ends of the peach as 

 it grows on the branch. It makes its appearance in 

 the form of very minute black spots or dots from about 

 the middle to the last of June upon early varieties in 

 New Jersey, Delaware and Maryland. Farther south 

 it occurs correspondingly earlier. It may be readily 

 controlled by thorough summer spraying with the self- 

 boiled lime-sulfur. 



Peach-mildew most frequently occurs along the 

 northern limits of peach-production near the Great 

 Lakes, and in the Northwest. This is probably because 

 of the wider extremes of temperature during the 

 day. 



Mildew appears in the form of a white powdery sub- 

 stance upon the leaves and fruit. It may do consider- 

 able damage to nursery stock in some cases. Sprayings 



