BOTRYTIS BLIGHT OF PEONIES 
This is a common and very important disease of the peony. There 
appear to be in fact two Botrytis blights so similar in symptoms as to 
be distinguished only by a careful examination of the pathogenes involved. 
SYMPTOMS 
On young shoots. Study photographs and specimens provided. 
OBSERVE :— : 
1. That when the plants first come up in the spring shoots 
from six to ten inches high, suddenly begin to wilt and fall to the ground. 
The entire shoot quickly withers and dries. . 
2. At the base of these wilting shoots, the brown rotten lesion 
usually involving the entire circumference of the stem and extending 
some distance above the surface of the soil. The wilting noted above 
is due to this basal stem-rot. ; 
3. Covering the surface of some of these lesions the greyish 
brown felty covering of conidiophores of the pathogene, appressed or 
broken away from the dry specimens. Very evident in fresh specimens. 
4. On some of the lesions in their more advanced stages, small 
black bodies the size of a pin-head imbedded in the cortical tissues; most 
usually found at the base of the stem where it was covered by the soil. 
These are the sclerotia of the pathogene. 
SKETCH (full page size) to show the symptoms in blighted young shoots. 
As the season advances shoots continue to wilt from lesions at their 
base. However, the proportion of such cases decreases rapidly as the 
stem-tissues mature and harden. Toward the middle of the season the 
stems attacked at the base wilt but do not fall over. The development 
of the lesion is much slower and the wilting is often preceded by a yellowing 
or a purpling of the foliage. 
Study such specimens and photographs as are available showing the 
characters of the stem-rot in the older shoots. 
Onthe buds. The bud-rot is the next symptom of the disease to develop 
after the stem-rot of the young shoots. The symptoms exhibited by 
affected buds are of two general types; the ‘‘bud-blast’” of the small 
immature buds when they are from the size of a pea to half an inch in 
diameter and the “‘bud-rot” which is the name applied to the disease 
as it manifests itself in affected buds after they are nearly or quite mature, 
just before blooming. 
Bud-blast. Examine the material available. oBSERVE:— 
: 5. Black or brown undeveloped small buds in the cluster. 
It is usually the first or leader-bud of the shoot that is affected. Note 
that some of the secondary buds are larger and healthy. They grow 
rapidly after the death of the main-bud. 
6. The brown felt of conidiophores with grey conidia. This is 
commonly wanting or difficult to detect with the naked eye especially 
in dry specimens. 
SKETCH to show bud-blast. 
Bud-rot. Examine one of the large buds provided. oBSERVE:— 
7. The general discoloration of the floral parts. The bud is 
killed. It fails to open. 
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