Snapdragon diseases and parasites
is some information about snapdragon diseases in the Texas Plant Disease Handbook
provided by Cygnus corporation. They have a special page for Snapdragon
List of diseases found in snapdragons:
- Alternaria alternata (Leaf Spot, Blattfleckenkrankheit)
still 55 In situ picture of cut leaf fragment infected with Alternaria
alternata. Note blackish spots and emerging fluid droplets.
still 56 In situ picture of leaf cutting. Aerial mycel formation.
still 57 In situ picture of leaf cutting. Aerial mycel formation and
still 58 In situ picture of leaf cutting. Late stage.
pict 1 Light microscopic picture of Alternaria alternata conidia. Note
typical elongated shape and cell walls in transversal and longitudinal
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)
- 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.
still 32 (24246 Bytes) Infected leaf, ventral (lower) surface.
still 33 (32514 Bytes) Infected leaf, ventral (lower) surface.
still 34 (35730 Bytes) Infected stem.
still 35 (43036 Bytes) Infected inflorescence.
still 36 (20705 Bytes) Infected leaf, ventral (lower) surface, showing
"majic circles" of secondary infections.
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.
still 44 (44891 Bytes) Infected plant, wilt on leaves.
still 45 (42951 Bytes) Infected plant, wilt on leaves.
still 46 (87727 Bytes) Comparison between uninfected (left) and infected
still 47 (89277 Bytes) Comparison between uninfected (left) and infected
still 48 (64839 Bytes) Comparison between uninfected (left) and infected
plants (right). A complete experiment has been destroyed by Verticillium.
still 49 (76710 Bytes) Comparison between uninfected and infected
- Verticillium dahliae (Wilt, Cotton Wilt)
- (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
still 42 (34239 Bytes) Caterpillar on leaf.
still 43 (5801 Bytes) Closeup of caterpillar.
still 50 (34239 Bytes) Caterpillar on leaf. Later stage.
still 51 (34239 Bytes) Caterpillar on leaf. Later stage.
still 52 ( Bytes) Caterpillar on leaf. Later stage.
still 53 ( Bytes) Caterpillar on leaf. Later stage. Emerging of
parasitic wasp larvae.
still 54 ( Bytes) Caterpillar on leaf. Later stage. Emerging of
parasitic wasp larvae.
- Leaf mining insect
still 40 (38907 Bytes) A leaf (left) has been penetrated by some mining
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This page has last been modified on August 27, 1997.