470 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



common storage or delayed in reaching 

 cold storage usually becomes affected. The 

 disease has been particularly annoying to 

 fruit growers who have attempted to keep 

 prize specimens of the Jonathan in cellar 

 storage for exhibition purposes. The 

 growers of Esopus ( Spitzenhurg ) in Ore- 

 gon and Washington have perhaps suf- 

 fered most from this trouble, the spots 

 often developing on the fruit en route to 

 the Eastern markets. 



The Jonathan is the most susceptible 

 variety grown in the East, and its com- 

 mercial standing is greatly impaired on 

 account of this weakness. The disease is 

 now rather commonly known among 

 apple growers as the "Jonathan spot," 

 and for that reason the writers have 

 adopted the name "Jonathan fruit spot." 

 The Esopus is almost, if not quite, as 

 susceptible to the disease as the Jona- 

 than, and the Yellow Newtown apparently 

 ranks third in degree of susceptibility. It 

 has also been observed to a very slight 

 extent on the Grimes. Arkansas Black, 

 and a few other varieties of less impor- 

 tance. 



Dry weather during the summer is ap- 

 parently favorable to the development of 

 the Jonathan fruit spot. It was very bad 

 in 1910 and 1911, both of which were dry 

 seasons, while in 1912, a comparatively 

 wet season, it was not common on East- 

 ern-grown fruit. In the fall of 1911 the 

 spotting was particularly serious on the 

 Jonathan, specimens having been re- 

 ceived from practically every section of 

 the country where that variety is grown. 



ISiiminary of f'oncliisioiis 



The investigations conducted by the 

 writers seem to warrant the following 

 conclusions: 



(1) The Jonathan fruit spot of the 

 apple is due neither to spraying with 

 arsenate of lead nor to a specific organ- 

 ism. 



(2) It is probably a physiological 

 trouble, falling in the same category as 

 the bitter pit or Baldwin spot. 



(3) Early picking, prompt cold stor- 

 age, and immediate consumption of the 



fruit after removal from storage, will 

 largely obviate losses from the disease. 

 W. M. Scott, 



Formerly Pathologist, and 

 John W. Roberts, 

 Assistant Pathologist, 

 Fruit-Disease Investigations. 



Leaf Bliisrht 



Sphaeropsis vialorum 



See Black Hot. 



Leaf Spot 



Sphaei'opsis malorum 



See Black Rot. 



Leaf Spot or Fro^ Eye 

 There is a common leaf spot disease of 

 apple trees in which the dead spots show 

 the presence of pycnidia. This trouble 

 is really due to the black rot fungus 

 (Sphaeropsis malorum Pk.) but at times 

 another fungus (Coniothyriim pirini 

 Sacc), comes in afterwards. In the later 

 season the second type develops in con- 

 centric areas to which the common name 

 of "Frog Eye" has been given. Yet other 

 forms of leaf spot due to spray injuries 

 also occur, but are easily distinguishable 

 from the two first named. It has been 

 shown that control of the black rot fun- 

 gus keeps the leaf spot in hand, but early 

 treatments should be made. 



A. D. Selby. 

 Lichens 

 Not infrequently complaints are re- 

 ceived, particularly from Atlantic coast 

 towns, with regard to fruit trees being 

 over-run by lichens, sometimes improp- 

 erly called "mosses" by orchardists. While 

 mosses are not uncommon on old, neg- 

 lected fruit trees, lichens are much more 

 frequent. The latter are foliacious 

 growths of various colors, the more com- 

 mon being grayish and found Indiscrimi- 

 nately upon trunks of trees, rocks, old 

 fence boards, etc. Quite frequently these 

 lichens are found in large numbers upon 

 orchard trees — apples, pears and plums — 

 particularly so in the states farther south. 

 In temperate climates lichens occurring 

 on tree trunks are not considered to be 

 parasitic. In the tropics there is evi- 

 dence that one or more kinds are prob- 



