May, 19 1 .5 
T HE G A R DEN M AGAZIN E 
213 
tion (by burning) of diseased leaves, before 
the fungus can produce a crop or spores to 
infect other leaves, is the only practical 
way of controlling the trouble. 
The anthracnose affects both stems and 
leaves of the peony, producing rather small 
dark purple-red spots with whitish centres. 
On the stems the spots or cankers may run 
together to form long strips of dead tissue, 
in severe cases weakening the stalk so it 
may break over. The spots on the leaves 
are circular in severe cases, coalescing but 
usually scattered. The light colored centre 
sometimes drops out. To prevent the 
appearance of the disease another season 
cut and burn the tops early, cutting at or 
below the surface of the soil. 
The most destructive and most fre- 
quently appearing disease of the peony 
plant is without doubt the Botrytis blight. 
This disease affects all parts of the plant 
except the root and it is possible that one 
of the crown or root rots may be but a 
manifestation of this malady. The Bo- 
trytis blight is often very destructive, espe- 
cially in wet seasons. All varieties of the 
peony seem to be about equally susceptible. 
The first symptom of this disease 
appears shortly after the young 
shoots appear above ground and 
before they have expanded their 
foliage. Affected shoots suddenly 
wilt and fall over. Examination 
shows them to be rotting at the 
base, usually at the level of the 
ground. It is seldom that all the 
shoots in a cluster wilt, though not 
infrequently half or more of them 
may be thus destroyed. The buds 
afe next to be attacked. Some- 
times it is the very young buds 
which turn black and die. They 
are said to have “blasted.” The 
buds are more often attacked, how- 
ever when full grown and just before 
they open. They turn brown and 
fail to expand. On breaking or 
cutting into the diseased bud it is 
found to be a mass of rather soft 
brown rotten petals. The rot usually 
extends down the stem from the diseased 
bud for several inches. The leaves are 
this disease forms small tuberlike black 
bodies in the diseased stems. These sclerotia, 
as they are called, are about the size of a pin 
head and are produced in great numbers just 
under the epidermis. Here on the old 
stems or stubble they pass the winter in a 
dormant state. In the spring as the new 
peony shoots are coming up these sclerotia 
germinate, producing stalks bearing minute 
spores. These spores are blown by the 
wind or splashed by the rain against the 
young shoots near by. Here they germin- 
ate, and infect the tender stalks. Within 
four or five days thereafter the stalks wilt 
and droop as a result of the rotting of the 
tissues by the pathogen. In a few days 
more, these dying young shoots are covered 
with a felt of spore stalks and spores, a 
new crop to serve for the inoculation of 
other shoots and growing buds. The un- 
opened buds of the peony exhude a sugary 
secretion in which the spores of the Botrytis 
germinate very readily. Ants which visit 
the buds to lap up the sweetness run over 
diseased spore covered stalks, on their way 
up to the buds on healthy stems and so 
bring the spores on their feet. These 
spores are left behind as the insect 
wades about in the sugary exhudate. 
A few days later the bud begins to 
turn brown and rots as already des- 
cribed. The diseased bud in its 
turn now becomes covered with the 
spores of the pathogen which are 
distributed by ants and wind to other 
buds and to the leaves, there to 
germinate and produce more rotting 
and blighting. 
This Botrytis disease is to be con- 
trolled only by the most rigid and 
prompt eradication of diseased 
shoots, buds and leaves. Spraying 
has been tried, but has not proven 
very satisfactory. Inspect the plants 
every day until after blossoming time 
at least, removing every wilted stalk 
or diseased bud and burn them. Cut 
the tops early in the autumn, remov- 
ing the soil from the crowns and cut- 
ting the stems down as close as pos- 
sible and burn the refuse. It is in the old 
stubble that this pest lives from year to year. 
next to show the effects of the blight fungus. 
Large dead spots make their appearance, 
usually starting at the tip of the leaf. The 
affected part turns brown, dries out quickly 
and becomes brittle. The blighting of the 
foliage is usually most apparent during 
the latter part of the season. It is especi- 
ally severe if the 
weather be wet. 
The Botrytis fun- 
gus which 
causes 
This root is badly affected by root gall and is not worth 
planting 
When the plants show anthracnose cut the tops early in fall and burn them 
(Purple-red spots with whitish centres) 
The strange mosaic disease which apparently does not 
seriously injure 
Blighted leaves, another evidence of the Botrytis. The 
under surface has the spores 
Leaf blotch. Prompt removal and burning of the leaves 
is the remedy 
