Snapdragon diseases and parasites
There is some information about snapdragon diseases in
the Texas Plant Disease
Handbook provided by Cygnus corporation. They have a special page for
Snapdragon diseases.
List of diseases found in snapdragons:
- Alternaria alternata (Leaf Spot, Blattfleckenkrankheit)
- kst still 55 In situ picture of cut
leaf fragment infected
with Alternaria alternata. Note blackish spots and emerging fluid
droplets.
- kst still 56 In situ picture of
leaf cutting. Aerial mycel formation.
- kst still 57 In situ picture of
leaf cutting. Aerial mycel formation and discoloration.
- kst still 58 In situ picture of
leaf cutting. Late stage.
- wgi pict 1 Light microscopic picture
of Alternaria alternata conidia. Note typical elongated shape and
cell walls in transversal and longitudinal directions.
- wgi pict 2 Light microscopic picture
of Alternaria alternata conidia.
- Botrytis cinerea (Gray Mold)
- Cercospora antirrhini (Leaf Spot)
- Colletotrichum antirrhini (Anthracnose)
- Ooidium spp. (Powdery Mildew)
- Phytophthora cinnamomi (Root rot)
described in
- Puccinia antirrhini (Rust)
Very common in late summer. Affects allmost all plants. Several forms of
the fungus have been described. Against some of them limited resistance
has been detected, against other forms no resistance was found. A claim
for a monogenic factor R (for resistance) could not be veryfied so far.
- kst still 32 (24246 Bytes) Infected
leaf, ventral (lower) surface.
- kst still 33 (32514 Bytes) Infected
leaf, ventral (lower) surface.
- kst still 34 (35730 Bytes) Infected
stem.
- kst still 35 (43036 Bytes) Infected
inflorescence.
- kst still 36 (20705 Bytes) Infected
leaf,
ventral (lower) surface, showing "majic circles" of secondary infections.
- kst still 37 (21987 Bytes) Infected
stem. Side shoots affected.
- Phyllosticta antirrhini (Blight)
- Verticillium albo-atrum (Wilt)
Has been found to destroy a complete set of several hundred plants
completely. Different strains seem to have different susceptibilities.
Leaves become dry and plants wither.
- kst still 44 (44891 Bytes) Infected
plant, wilt on leaves.
- kst still 45 (42951 Bytes) Infected
plant, wilt on leaves.
- kst still 46 (87727 Bytes)
Comparison between uninfected (left) and infected plants (right).
- kst still 47 (89277 Bytes)
Comparison between uninfected (left) and infected plants (right).
- kst still 48 (64839 Bytes)
Comparison between uninfected (left) and infected plants (right). A complete
experiment has been destroyed by Verticillium.
- kst still 49 (76710 Bytes)
Comparison between uninfected and infected plants.
- Verticillium dahliae (Wilt, Cotton Wilt)
described in
- (Cotton Root Rot)
- (Root Knot)
- (Southern Blight)
- (Stem and Root Rot)
- Scutigerella immaculata (Garden centipede). This organism is known
to infect seedlings and feeds on roots. Older plants may not be damaged.
- Butterflies feeding on snapdragons:
- Hyles lineata (Striped Hawk-moth, Bedstraw Hawk-moth,
Linienschärmer).
- Stenoptilodes taprobanes
- Pyrrhia umbra (Bordered Sallow)
- Xestia baja (Dotted Clay)
- Unknown caterpillar
- kst still 42 (34239 Bytes)
Caterpillar on leaf.
- kst still 43 (5801 Bytes)
Closeup of caterpillar.
- kst still 50 (34239 Bytes)
Caterpillar on leaf. Later stage.
- kst still 51 (34239 Bytes)
Caterpillar on leaf. Later stage.
- kst still 52 ( Bytes)
Caterpillar on leaf. Later stage.
- kst still 53 ( Bytes)
Caterpillar on leaf. Later stage. Emerging of parasitic wasp larvae.
- kst still 54 ( Bytes)
Caterpillar on leaf. Later stage. Emerging of parasitic wasp larvae.
- Leaf mining insect
- kst still 40 (38907 Bytes) A leaf
(left) has been penetrated by some mining insect.
This page is part of the
Snapdragon Home Page.
The URL of this page is
http://www.mpiz-koeln.mpg.de/~stueber/snapdragon/snapdragon_diseases.html
If you have any comments, additions or corrections to this page of general
interest you are invited to use the
Snapdragon Guest Book.
For personal comments please write to the author(s) of this page or to
Kurt Stueber.
This page has last been modified on August 27, 1997.