480 INSECTS AFFECTING VEGETATION 



judgment as to whether the first application may be safely omitted. 

 Where peach scab is the chief trouble, and brown-rot and curculio 

 are of only minor importance, as may be the case in some of the 

 Allegheny Mountain districts, satisfactory results may be had from 

 two applications, namely, the first with self-boiled lime-sulphur and 

 arsenate of lead four to five weeks after the petals fall, and the sec- 

 ond treatment of the above schedule with self-boiled lime-sulphur 

 alone three to four weeks later. These two treatments, if thoroughly 

 applied, will control the scab and brown-rot, especially on the early 

 and midseason varieties, and will materially reduce curculio in- 

 juries. Even one application of the combined spray made about 

 five weeks after the petals fall would pay well, although this is 

 recommended only for conditions where it is not feasible to do more. 

 (F. B. 440.) 



Peach Leaf-Curl. Peach leaves affected with the curl can often 

 be detected as soon as the leaf buds have opened to a slight extent. A 

 roughened surface of the young leaf and an excess of coloring are 

 usually the first indications. As the young leaves rapidly assume 

 their normal size, this curling and arching of the blades is more 

 prominent. Sometimes there is distortion in a small area only, and 

 again the entire blade may be affected. The curling of the edges 

 of the leaves may be upward or downward, or the upper surface of the 

 leaf may be gradually arched from base to tip. When the leaf is full 

 grown, the diseased areas may be reddish green; but usually the 

 green color is largely lost and a pale discoloration characterizes dis- 

 eased parts. Not only are leaf and leaf-stalk affected, but the ter- 

 minal part of the shoot becomes much enlarged, and also pale in 

 color. The fungus is then thoroughly established in the tip of the 

 branch, and the significance of this is apparent later on. The leaves 

 soon become grayish or mealy in appearance. This appearance is 

 due to the fact that the fungus is fruiting, producing the spores which 

 are to disseminate the disease. After the grayish color appears, the 

 affected leaves gradually dry up and fall off. In this latitude the de- 

 foliation from such injuries usually occurs late in June. 



In the late stages of this curl disease, as with some other peach 

 diseases, gummy exudations are often noted on those twigs which are 

 enlarged by the fungus; or these may occur even on the large 

 branches where a diseased cluster of leaves has been attached. 



Defoliation of the entire tree does not necessarily mean the death 

 of the tree, but it does mean the death of many twigs, and lessened 

 vitality. New buds, or rather some of the sleeping or dormant buds 

 open and the tree attempts to supply itself with new and healthy 

 foliage. It is very seldom that this fresh foliage is badly affected by 

 the curl ; and it is possible to account for whatever curl is now evident 

 as having come directly from diseased buds or twigs. 



The new shoot growing out from a diseased terminal bud may 

 grow entirely out of the disease, but the swollen part remains below. 

 Thus, when the season's growth is done and the autumn at hand, 

 these swollen areas may mark out the recovery of shoots ; but they 



