PEACH DISEASES 



15G1 



probable that under Northwestern condi- 

 tions, should the disease become serious 

 enough to warrant special remedy, Bor- 

 deaux mixture applied in the middle of 

 August or first of September would con- 

 trol the disease. 



Seal) or lllack Spot 



Cladosporium carpophilum Thum. 

 This fungus is a serious drawback in 

 the growth of certain varieties which 

 seem susceptible. These are Morris, White, 

 Salway and some other late sorts. It 

 causes dark spots upon the fruit followed 

 by cracking and entrance of the rot fun- 

 gus with serious results. To control this 

 disease, spraying with self-boiled lime- 

 sulphur is the remedy to be applied at 

 intervals of two to three weeks after 

 foliage appears. 



A. D. Selby 



Sooty Mold of the Peach 



When the fungus is present, the bark 

 of the trunk and inner limbs become cov- 

 ered with a sooty mold, giving the bark 

 a black appearance; it later in the season 

 covers the foliage and fruit, interfering 

 with the health of the tree and the de- 

 velopment of the fruit, rendering It un- 

 sightly. 



Where winter spraying is done, very 

 little if any is found; orchards affected 

 with it should be sprayed while trees are 

 dormant, with lime and sulphur solution, 

 or Bordeaux mixture. 



J. H. Funk, 



Boyertown, Pa. 



Stem BUght 



It is due to a specific fungus which 

 attacks the stems of nursery stock, caus- 

 ing a constriction, and this is in line with 

 the effects of the fungus described from 

 Europe as a constriction or lacing dis- 

 ease. Infection may be prevented by 

 treatment with fungicides. 



A. D. Selby 

 AVIntcr Injury 



In cold climates severe freezing of win- 

 ter often injures the trunk and branches 

 of peach trees. The killing back of new 

 growth is a common occurrence. Also 

 the killing of the trunk on one side, 

 usually the west or southwest. The indi- 



cations are that where there has been 

 late growth of the trees followed by 

 severe winter cold, such injury may be 

 expected. Late cultivation or irrigation 

 should therefore be avoided. 



Yellows 



Peach yellows is a serious, contagious 

 disease of this fruit. Only in certain 

 seasons may we find yellowish color as a 

 marked symptom of affected trees. The 

 true symptoms of yellows are: 1. Pre- 

 mature ripening of the fruit, which is 

 highly colored, often purplish spotted, and 

 has the flesh marbled with red. 2. The 

 premature growth of winter buds, result- 

 ing in excessive branching on new shoots, 

 and the development of slender, wiry 

 branched twigs. 3. Resting buds or ad- 

 ventitious buds are formed on the trunk 

 and branches; these grow into sickly 

 shoots with pale, narrowed leaves, and 

 usually become much branched, with tips 

 like veritable brooms. Aside from these 

 specific evidences of yellows, which serve 

 to distinguish yellow color from true yel- 

 lows disease, there are others less easily 

 described but none the less useful to the 

 practical observer. This disease may be 

 recognized late in the season by the late, 

 adventitious growth. The sources of dis- 

 ease are diseased trees or affected nursery 

 stock, more often the former. The rem- 

 edy is to remove and to burn the yellows 

 trees, root and branch, on the spot where 

 found. Dragging diseased branches may 

 spread yellows and all such trees are a 

 menace. To leave an open hole over win- 

 ter and replant the next year is a safe 

 practice. 



Recent investigations of this disease 

 show that it is due to an enzyme which 

 converts the leaf chloryphyll into a dis- 

 eased form, causing yellows conditions. 

 It is doubtless this enzyme which is trans- 

 mitted, as in the case of tobacco, by 

 actual contact. These discoveries have 

 changed in no way our method of hand- 

 ling the disease. 



Rosette of peach is a disease of the 

 Southern states which appears to be sim- 

 ilar in cause and transmission to peach 



yellows. A T^ c. 



A. D. Selby 



