470 
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 (Sprtzenburg) 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 Hast, 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. 
Sammary of Conclusions 
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. 
(8) Early picking, prompt cold stor- 
age, and immediate consumption of the 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
fruit after removal fiom stoiage, wy 
largely obviate losses t10m the disease 
W M Scors, 
Foimerly Patholoyist, and 
Jon W. Rozerrs, 
Assustant Pathologist, 
Fruit Discase Investwationgs 
Leaf Blight 
Sphaerops.s malorwm 
See Black Rot. 
Leaf Spot 
Sphaeropsis malorum 
See Black Rot. 
Leaf Spot or Frog 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 malorunm Pk) but at times 
another fungus (Comothyrium puri 
Sace ), comes in afterwards In the later 
season the second type develops in con. 
centric areas to which the common name 
of “Frog Hye” 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 Sexesy. 
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 laiter 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 evr 
dence that one or more kinds are prob- 
