June, 1890. 
113 
hardy and very productive. This is a very 
handsome, showy apple and will command 
the highest price in any market. We con- 
sider it a valuable apple and it vx ill succeed 
in a wide range of country. It was procur- 
ed by us twenty-five years ago from Penn- 
sylvania under the above name, but in many 
respects it corresponds with Sherman's Fav- 
orite and may possibly be the same. So far 
we have been unable to get specimens of 
both together to compare them. It is, how- 
ever, certain that this apple is known to but 
few under the above name as we have nev- 
er seen it mentioned since we procured it. 
— J. Stayjvian. 
Conducted by Prof. F. Lamson Scribner, 
Botanist, Experiment Station, Knoxville, Tenn. 
Apple-scab and its Treatment. 
Of the two hundred or more fungi which 
mycologists have found on the apple tree or 
its fruit the fungus which causes the 
“blight” of the leaves or the “scab"’ on the 
apple is the best known and by far the 
most injurious, at least to the crop. Wher- 
ever apples are grown for the market we 
h«ar of their being more or less damaged 
by the “scab,” or “black-spot” as some call 
it. From Maine to California it is well 
known and its ravages are severely felt by 
many orchardists throughout the breadth 
of our country. It is in the cooler regions 
* that the disease is most severe; it is less 
prevalent in the warmer Southern States. 
But it is in the northern sections that the 
bulk of our apple crop is produced and the 
climate most favorable to the crop is also 
most congenial to the fungus. Large or- 
chardists have assured us that their indi- 
vidual losses on account of the “scab” 
sometimes amounted to a thousand dollars 
or more. The affected apples do not attain 
their normal size, nearly all must be classed 
as • seconds” or rated with those of value 
only for cider making. 
In some States the loss from Apple-scab 
is said to amount to one half the crop; the 
general annual loss from the disease is 
placed at from one-fourth to one-sixth of 
the crop. Several years ago the Secretary 
of the Illinois Horticultural Society esti- 
mated that the loss in his State would 
amount to $400,000. The importance of 
gaining a practical knowledge of the habits 
of a fungus vx hich so seriously affects one 
of our staple crops and of learning how to 
pievent its attacks is plainly evident. There 
are very many whom we know feel a vital 
nterest in this subject and will be very 
glad to learn that an efficient remedy has 
been found for the disease. 
It seems almost superfluous to describe 
here the external characters of Apple-scab. 
Every orchaidist and dealer in apples is 
familiar with the appearance of the disease. 
Our illustration (Fig. 273), showing an af- 
fected fruit, will at once call the disease to 
mind. The fact that the same fuugus also 
attacks the leaves and young shoots is not 
so generally well known. On the leaves 
the first manifestations of the presence of 
the parasite are the appearance, here and 
there over the surface, of smoky, olive- 
green spots, rounded in outline. The older 
spots range from 1 g to % an inch in diam- 
eter, or they may appear as large, irregular 
blotches by the running together of several 
of the spots first formed. They are for the 
most part confined to the upper side of the 
leaf which often becomes much distorted 
through the unequal development of the 
two surfaces. The color of the older spots 
is nearly black and their surface somewhat 
velvety. The growth of the young shoots 
is often seriously checked through the di- 
rect action of the fungus upon them and 
when the foliage of a tree is much affected 
its nutrition must be seriously impaired. 
The tree is rendered 
less able to withstand 
the severe cold of the 
winter season and is 
Fig. Spores of fun- |.p,-,apy.£.,l more likelv 
gus of Apple Scab. One renaereu more OReiy 
germinating. to injury from early 
or late frosts. 
Cool weather, especially if accompanied 
with an excess of moisture, favors the de- 
velopment of the fungus and it is during 
such periods that it vegetates and spreads 
most rapidly. Figure 274 is an enlarged 
drawing of a section made through the 
edge of a “scab” spot from an apple which 
had been kept for several days in a moist 
atmosphere, and exhibits a luxuriant 
growth of the Apple-scab fungus. At ep is 
the cuticle of the apple, its broken edge turn- 
ed back by the outward growth of the par- 
asites/illustrates the body of the fungus 
as seen in section under a strong micro- 
scope; c epidermal cells. The growth of 
the fungus does not extend into the deeper 
tissues but is limited to the region between 
the cuticle and epidermis proper. Some- 
times the cells composing the latter are 
turned brown or even destroyed by the par- 
asite and sometimes a few of the underly- 
ing pulp-cells of the fruit have their con- 
tents discolored, but the fungus itself never 
penetrates these. After the fungus has 
groxvn for a longer or shorter time beneath 
the cuticle it breaks through this covering 
and becomes exposed to the air. It is then 
ready to fruit or produce spores, which 
amounts to the same thing. The spores are 
borne on short upright stalks the free ends 
of which are often much longer than are 
those in our illustration (Fig. 274), where 
the still attached spores are shown at s. 
They are oval or pear-shaped and dark 
olive-brown in color like the filaments 
which support them. They are produced 
in great numbers throughout the season of 
growth and on stored fruit, and are ready 
to germinate as soon as mature. We have 
seen them germinating while still attached 
to their supporting stalks. They will ger- 
minate in an atmosphere saturated with 
moisture and at a comparatively low tem- 
perature. A germinating spore is shown in 
Figure 275. The germ-tube from a spore 
resting upon the surface of an apple pene- 
trates the cuticle between which and the 
epidermis further growth is continued re- 
sulting finally in the rupture of the cuticle 
and the production of a new crop of spores. 
The development of the Apple-scab fun- 
gus is therefore very simple. No other 
stage than that here described and figured 
is known. The fungus lives through the 
winter in the fallen leaves, certainly in the 
harvested fruit and very likely also in the 
young shoots or autumn-formed buds. From 
the latter it doubtless spreads to the new 
growths of the following season and thus 
the pest is perpetuated from year to year. 
Treatment. — It is very well known that 
some varieties of apples are more liable to 
“scab” than others and in selecting varieties 
for culture the fruit-grower will take this 
fact into consideration. This means of avoid- 
ing the disease cannot always be depended 
on for, as is also pretty well known, a given 
variety may be quite “resistant” in one sec- 
tion of the country while in some other re- 
gion it may prove most “susceptible.” 
Direct treatment by the use of fungicides 
is the only method by which we may hope 
to overcome the “scab.” In the report of 
the U. S. Department of Agriculture for 
1887, we recommended a course of treat- 
ment winch has since proved most satisfac- 
tory so far as it has been carried out. The 
course laid down was as follows: 
“(1) In early spring before the buds have 
commenced to expand, spray the trees 
thoroughly with a solution of sulphate of 
iron, using 4 pounds of the iron sulphate to 
4 gallons of water. 
(2) As soon as the fruit has set, apply the 
Bordeaux mixture or one of the modified 
preparations of eau celeste [including the 
ammoniacal solution of carbonate of cop- 
per]. 
