166 
September, 1890. 
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Conducted bt Prof. F. Lamson-Scribner, 
Director and Botanist. Experiment Station. 
Knoxville, Tennessee. 
The Entomosporium of the Pear and 
Quince. 
There is a fungus which attacks both the 
Pear and Quince — young shoots, leaves and 
fruit — named by mycologistsEntomosporium 
maculatum. It has been variously named 
“Leaf -blight of the Pear," “Cracking of 
the Pear," “Quince-leaf Blight," etc., by 
popular writers, but as the term “blight" has 
been applied to a great variety of fungus 
diseases, and in the case of the Pear is 
applied to a special disease caused by an 
organism very different from the Entomos- 
porium. its use is ambiguous and likely to 
lead to confusion. We think it best to 
adopt, in the present case at least, the gen- 
eric name of the fungus ( Entomosporium ) 
adding the name of the plant attacked, to 
indicate which particular species of the 
genus is meant. 
This fungus, or the disease which it 
occasions, has been known both in this 
country and in Europe for many years and 
something is said about it in all our more 
important works on the Pear or Quince. It 
is very fully described and illustrated in 
the Annual Report of the U. S. Dept, of 
Agriculture for 1888. The figures given 
here, excepting the Quince leaf, were re- 
drawn from those in this report. Last year 
the disease was treated successfully for the 
first time by agents of the Department (See 
Bull. 11, Sect. Veg. Pathol p 46). 
We have seen this disease in many parts 
of the country, on the pear particularly in 
New Jersey and on the Quince wherever we 
have seen this tree, and our attention has 
very recently been called to it by the receipt 
of diseased Quince leaves from a corres- 
pondent in western New York, who af- 
firms that the fruit of that tree is often des- 
troyed or rendered wholly unfit for market 
from this cause. Scattered over the leaf- 
surface and showing on both sides are num- 
erous, usually round, brownish-red spots 
with sharply defined outlines and a central 
black point. Often several neighboring 
spots run together or the leaf tissue between 
them dies and thus are formed patches of 
considerable size and irregular outline. 
Such patches are most frequent along the 
margins of the leaves, these becoming dried 
and curled up. The vitality of the leaves 
is, after a time, seriously affected, they lose 
their hold upon the branches and fall pre 
maturely. Diseased leaves of both Pear 
and Quince are shown in figure 315 the 
brown spots and patches are indicated by 
the shaded portions. The spots on the Pear 
leaves are usually smaller than those on 
the Quince, rather darker colored, often 
less sharply defined an 1 have a reddish 
discoloration of the tissues bordering them. 
The fungus attacks the shoots of the season, 
sometimes so severely" as to kill them and, as 
already stated, the action of this parasite 
upon the fruit often renders it unfit for 
market, its growth 
being checked com- 
pletely or made dis- 
torted and unsightly. 
In the case of the 
Pear the fungus often 
confines itself to one 
side of the fruit and as 
the other parts con- 
tinue to develop, this 
side cracks open to a 
greater or less depth; 
hence the name — 
‘ ‘Cracking of thePear" 
— which we some- 
times hear applied 
to the disease. A 
characteristic e x- 
ample of this crack- 
ing of the fruit is 
shown in figure 314 
This Entomosporium 
Fig. 315. a. leaf of is to the Pear and 
Quince.b.leaf of Pear;each _ . 
attacked by Blight. Quince growers a 
very serious pest. Its attacks begin very 
early in the summer and continue through- 
out the season. We have seen Quince trees 
defoliated from its ravages by the first of 
August and have heard of cases of young 
Pear orchards being entirely stripped of 
their leaves by July 4, from the same cause. 
Such a wholesale destruction of the foliage 
cannot fail to materia’ly injure the vitality 
and longevity of the trees themselves 
and certainly diminish the product of suc- 
ceeding crops. It is on young nursery 
stock that the disease is most severe, in 
fact, nurserymen have not infrequently 
been forced to give up the propagation of 
the Pear on account of its great destructive- 
ness. 
In order to see the 
characters of the 
fungus which does 
so much injury we 
make a very thin 
section through one 
of the black points 
found in the center 
of the brown spots, 
for it is in these that 
the fungus reaches 
its fruiting stage, 
and examine it un- 
der the microscope. 
T ... Fig. 314. Cracking of the 
In this manner we p ea r. 
get a view like that shown in figure 313. 
Below are the long palisade cells of the leaf 
tissue upon which rests the epidermis. 
These cells are much shrunken and their 
contents changed to a dark brown. Grow- 
ing between them may be seen a number of 
slender filaments that constitute a part of 
the mycelium of the fungus w hich is shown 
more painly above just beneath the cuticle, 
which it has broken through. Here are 
seen in various stages of development the 
very peculiar spores. Several of these 
spores, detached from their supports, are 
also shown in the figure. As seen under 
the microscope the spores have somewhat 
the appearance of minute insects and it is 
from this resemblance that we get the name 
Emtomosporium, or insect-like spores. Upon 
the fallen leaves which have suffered from 
the disease there has been found during the 
later winter or early spring months, a fun- 
gus growth thought by some to be the ma- 
ture or perfect stage of development of our 
Entomosporium. In this stage the spores 
are tw o-celled and enclosed, usually to the 
number of eight, in delicate, elongated 
sacks, all being surrounded by a rather 
dense and hard black covering. These well 
protected spores, if really belonging to the 
Entomosporium , assist in the propagation 
of the fungus and are doubtless designed 
to preserve it from destruction by accident 
or through the severity of the winter season. 
Fig. 313. FuDgus of Pear-loaf Blight and Quince- 
leaf Blight. Also causes “Cracking” of Pears, m. 
mycelium, s. spores. 
Treatment. — Very little can be done in 
preventing the ravages of this Entomos- 
porium by pursuing special methods of cul- 
ture or by selection of varieties, although in 
certain localities some varieties appear to 
be more resistant than others. Happily, 
however, the disease responds readily to 
treatment with the sulphate of copper com- 
pounds. The Bordeaux mixture applied 
early in the season, as soon as the first 
leaves are formed, and repeated at intervals 
of from ten to fifteen days, has completely 
preserved the foliage on seedling pears in 
nurseries where the young trees not so 
treated were denuded of leaves by midsum- 
mer. By a similar treatment of older 
trees — both the Pear and Quince — have been 
preserved from the disease in orchards where 
untreated trees suffered severely. In ad- 
dition to this treatment during the growing 
season we would recommend that the trees 
be sprayed with a simple solution of sul- 
phate of copper (1 lb to 5 gal. of water) just 
before the buds begin to swell in the spring. 
Your paper is the most valuable I have yet seen of Its 
size. Ittreats specifically on subjects heretofore written 
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consider each paper worth twice the subscription price 
for the entire year, — R. M. Darnai.l, Lake Co., Tenn. 
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I change my decision and send you my subscription 
for two years from Jan. 1st. ’90. 
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