Disease snapshots

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

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

  • Blossom-end Rot of Tomato

    blossom end rot

    Causal agent: Insufficient calcium
    Pathogen type: Abiotic
    Management: Fertilization
    Photo credit: Dhruba Dhakal

  • Cedar-apple Rust on Juniper

    cedar apple rust

    Causal agent: Gymnosporangium spp.
    Pathogen type: Fungi
    Management: No need to control
    Photo credit: MU-PDC client

  • Cedar-hawthorn Rust

    cedar hawthorn rust

    Causal agent: Gymnosporangium globosum
    Pathogen type: Fungi
    Management: No need to control
    Photo credit: Katie Kammler

  • Cedar-quince Rust

    cedar quince rust

    Causal agent: Gymnosporangium clavipes
    Pathogen type: Fungi
    Management: No need to control
    Photo credit: Patrick Byers

  • Cicada Damage

    cicada damage

    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

    Causal agent: Crioceris asparagi
    Pathogen type: Insect
    Management: Biological control and insecticide
    Photo credit: Debi Kelly

  • Eight-spotted Forester Caterpillar

    eight-spotted forester caterpillar

    Causal agent: Alypia cotomaculata
    Pathogen type: Insect
    Management: No need to control.

  • Elm Cockscomb Gall

    elm cockscomb gall

    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

    Causal agent: Aproceros leucopoda
    Pathogen type: Insect
    Management: Eradication and pesticide
    Photo credit: Heather Huntington

  • Flatheaded Wood Borers

    flatheaded wood borers

    Causal agent: Buprestidae
    Pathogen type: Insect
    Management: Prevention and sanitation

  • Hackberry Nipple Galls

    hackberry nipple galls

    Causal agent: Pachypsylla celtidismamma
    Pathogen type: Insect
    Management: Insignificant damage and no effective way to control

  • Hollyhock Rust

    hollyhock rust

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

  • Horned Oak Gall

    horned oak gall

    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

    Causal agent: HVX
    Pathogen type: Virus
    Management: Use virus free plants

  • Iron Chlorosis

    iron chlorosis

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

  • Japanese Maple Scale

    japanese maple scale

    Causal agent: Lopholeucaspis japonica
    Pathogen type: Insect
    Management: Sanitation, dormant oil and insecticide
    Photo credit: Morgan Goodnight

  • Juniper Bagworms

    juniper bagworms

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

  • Mealybugs

    mealybugs

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

  • Pear Rust (Cedar-hawthorn Rust)

    pear rust

    Causal agent: Gymnosporangium globosum
    Pathogen type: Fungi
    Management: Preventative fungicide application and sanitation

  • Powdery Mildew on Bee Balm

    powdery mildew on bee balm

    Causal agent: Golovinomyces monardae
    Pathogen type: Fungi
    Management: Proper sunlight, irrigation and fungicide
    Photo credit: Katie Kammler

  • Scales on Philodendron

    scales on philodendron

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

  • Spittlebugs on Mint

    spittlebugs

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

  • Tar Spot of Maple

    tar spot of maple

    Causal agent: Rhytisma spp.
    Pathogen type: Fungi
    Management: Preventative fungicide application and sanitation.

  • Tomato White Mold

    tomato white mold

    Causal agent: Sclerotinia sclerotiorum
    Pathogen type: Fungi
    Management: Sanitation
    Photo credit: MU-PDC client

  • Virgin Tiger Moth

    virgin tiger moth

    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

    Causal agent: Arilus cristatus
    Pathogen type: Insect
    Management: Beneficial insects. No need to control.