These disease snapshots cover a broad range of plant diseases such as fungi, bacteria, viruses, insects and abiotic stresses. By presenting a representative digital image and a brief description, the MU Plant Diagnostic Clinic aims to provide you with a quick and accurate diagnosis to solve your plant problems. In contrast to sample highlights, this section may include some insignificant but very interesting plant diseases that could broaden your knowledge of plant pathology.

American Dagger Caterpillar
american dagger caterpillar
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Causal agent: Acronicta americana
Pathogen type: Insect
Management: Beware!! Poisonous!! Look it up before you pick it up.
Photo credit: MU-PDC client

Bacterial Canker of Tomato
bacterial canker of tomato
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Causal agent: Clavibacter michiganensis subspecies michiganensis
Pathogen type: Bacterium
Management: The use of pathogen-free seeds.
Photo credit: Morgan Goodnight

Birch Sawfly Larvae
birch sawfly larvae
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Causal agent: Cimbex femoratus
Pathogen type: Insect
Management: Tolerate it.
Photo credit: James Glenn

Black Scale on Jasmine
black scale on jasmine
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Causal agent: Saissetia oleae
Pathogen type: Insect
Management: Scrape the scale off or use insecticidal soap.

Blossom-end Rot of Tomato
blossom end rot
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Causal agent: Insufficient calcium
Pathogen type: Abiotic
Management: Fertilization
Photo credit: Dhruba Dhakal

Blue Winged Wasp
blue winged wasp
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Causal agent: Scolia dubia
Pathogen type: Insect
Management: Beneficial pollinator. No need to control.

Cedar-apple Rust on Juniper
cedar apple rust
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Causal agent: Gymnosporangium spp.
Pathogen type: Fungi
Management: No need to control
Photo credit: MU-PDC client

Cedar-hawthorn Rust
cedar hawthorn rust
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Causal agent: Gymnosporangium globosum
Pathogen type: Fungi
Management: No need to control
Photo credit: Katie Kammler

Cedar-quince Rust
cedar quince rust
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Causal agent: Gymnosporangium clavipes
Pathogen type: Fungi
Management: No need to control
Photo credit: Patrick Byers

Cicada Damage
cicada damage
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Causal agent: Cicada bugs
Pathogen type: Insect
Management: Removal of damaged branch, cover small tree with netting
Photo credit: Katie Kammler

Common Asparagus Beetle
common asparagus beetle
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Causal agent: Crioceris asparagi
Pathogen type: Insect
Management: Biological control and insecticide
Photo credit: Debi Kelly

Common Orange Lichen
common orange lichen
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Causal agent: Xanthoria parietina
Pathogen type: Lichen
Management: No need to control.
Photo credit: James Glenn

Eight-spotted Forester Caterpillar
eight-spotted forester caterpillar
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Causal agent: Alypia cotomaculata
Pathogen type: Insect
Management: No need to control.

Elm Cockscomb Gall
elm cockscomb gall
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Causal agent: Cockscomb gall aphid (Colopha compressa)
Pathogen type: Insect
Management: No need to control as the galls don't cause significant damage.

Elm Zigzag Sawfly
elm zigzag sawfly
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Causal agent: Aproceros leucopoda
Pathogen type: Insect
Management: Eradication and pesticide
Photo credit: Heather Huntington

Fall Webworm
fall webworm
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Causal agent: Hyphantria cunea
Pathogen type: Insect
Management: Not necessary if not severe.
Photo credit: TreeSMARTtrade

Flatheaded Wood Borers
flatheaded wood borers
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Causal agent: Buprestidae
Pathogen type: Insect
Management: Prevention and sanitation

Giant Swallowtail
giant swallowtail
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Causal agent: Papilio cresphontes
Pathogen type: Insect
Management: Chemical control applies to commercial citrus grower

Hackberry Nipple Galls
hackberry nipple galls
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Causal agent: Pachypsylla celtidismamma
Pathogen type: Insect
Management: Insignificant damage and no effective way to control

Heat Stress
heat stress
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Causal agent: Environmental stress
Pathogen type: Abiotic
Management: Good irrigation

Hollyhock Rust
hollyhock rust
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Causal agent: Puccinia heterospora
Pathogen type: Fungi
Management: Preventative fungicide application and sanitation
Photo credit: Katie Kammler

Horned Oak Gall
horned oak gall
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Causal agent: Callirhytis comigera
Pathogen type: Insect
Management: Insignificant damage and no effective way to control
Photo credit: MU-PDC client

Hosta Virus X (HVX)
hosta virus x
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Causal agent: HVX
Pathogen type: Virus
Management: Use virus free plants

Iron Chlorosis
iron chlorosis
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Causal agent: Iron deficiency and high PH
Pathogen type: Abiotic
Management: Fertilization
Photo credit: Katie Kammler

Japanese Maple Scale
japanese maple scale
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Causal agent: Lopholeucaspis japonica
Pathogen type: Insect
Management: Sanitation, dormant oil and insecticide
Photo credit: Morgan Goodnight

Juniper Bagworms
juniper bagworms
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Causal agent: Thyridopteryx ephemeraeformis (Haworth)
Pathogen type: Insect
Management: Hand-pick
Photo credit: Morgan Goodnight

Knopper Galls on Oak
knopper galls on oak
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Causal agent: Andricus quercuscalicis
Pathogen type: Insect
Management: No need to control.
Photo credit: James Glenn

Lace Bug on Oak
lace bug on oak
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Causal agent: Corythucha arcuata
Pathogen type: Insect
Management: High pressure water spray and application of insecticidal soaps and horticultural oil and pesticide.
Photo credit: James Glenn

Lynx Spider
lynx spider
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Causal agent: Oxyopidae spp.
Pathogen type: Insect
Management: No need to control

Mealybugs
mealybugs
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Causal agent: Planococcus spp.
Pathogen type: Insect
Management: Biological control and insecticide
Photo credit: Katie Kammler

Pear Rust (Cedar-hawthorn Rust)
pear rust
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Causal agent: Gymnosporangium globosum
Pathogen type: Fungi
Management: Preventative fungicide application and sanitation

 

Potassium Deficiency
potassium deficiency
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Causal agent: Potassium deficiency
Pathogen type: Abiotic
Management: Soil test and fertilization

Powdery Mildew on Bee Balm
powdery mildew on bee balm
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Causal agent: Golovinomyces monardae
Pathogen type: Fungi
Management: Proper sunlight, irrigation and fungicide
Photo credit: Katie Kammler

Powdery Mildew of Peperomia
powdery mildew of peperomia
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Causal agent: Podosphaera spp. or Erysiphe spp.
Pathogen type: Fungi
Management: Neem oil, milk, baking soda

Scales on Philodendron
scales on philodendron
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Causal agent: Scales
Pathogen type: Insect
Management: Sanitation, dormant oil and insecticide
Photo credit: Katie Kammler

Soybean Target Spot
soybean target spot
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Causal agent: Corynespora cassiicola
Pathogen type: Fungi
Management: Fungicide and resistant cultivar

Spittlebugs on Mint
spittlebugs
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Causal agent: Philaenus spp.
Pathogen type: Insect
Management: No significant damage. A quick blast of water.
Photo credit: Katie Kammler

Squash Bug
squash bug
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Causal agent: Anasa tristis spp.
Pathogen type: Insect
Management: Pick off early and insecticide.

Tar Spot of Maple
tar spot of maple
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Causal agent: Rhytisma spp.
Pathogen type: Fungi
Management: Preventative fungicide application and sanitation.

Tomato White Mold
tomato white mold
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Causal agent: Sclerotinia sclerotiorum
Pathogen type: Fungi
Management: Sanitation
Photo credit: MU-PDC client

Virgin Tiger Moth
virgin tiger moth
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Causal agent: Grammia virgo
Pathogen type: Insect
Management: No need to control. We don’t do that to anything associated with “tiger” in Missouri.

Wheel Bug Nymph
wheel bug nymph
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Causal agent: Arilus cristatus
Pathogen type: Insect
Management: Beneficial insects. No need to control.

White Fly on Christmas Cactus
white fly on christmas cactus
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Causal agent: Aleyrodidae spp.
Pathogen type: Insect
Management: Biological control or pesticide application.
Photo credit: James Glenn

White Pine Aphid
white pine aphid
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Causal agent: Cinara strobi
Pathogen type: Insect
Management: Neem oil and insecticidal soap
Photo credit: MU-PDC client

Woolly Bear Caterpillar
woolly bear caterpillar
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Causal agent: Pyrrharctia Isabella
Pathogen type: Insect
Management: No need to control.