Diseases of Native plants
Ram Sampangi
Krishna Mohan
University of Idaho, Parma ID 83660
and
Clinton C. Shock
Oregon State University
Malheur Exptl. Stn. Ontario, OR 97914
Forb Diseases
Objectives:
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Conduct surveys for new and/or emerging disease problems.
Identify unknown or little understood diseases in native systems.
Evaluation of plant cultivars for disease resistance/susceptibility.
Study the ecological and epidemiological aspects of diseases.
Significance:
 Diseases of economic crops are well known and studied but not the
diseases affecting native plants.
 Diseases of native plants are also part of the ecosystem.
 Prescreen plant materials for natural resistance to pests and diseases.
 Develop disease management practices.
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Forb species
Malheur Experiment Station, [OSU], Ontario, OR.
Species
Common name
Eriogonum umbellatum
Sulfur buckwheat
Penstemon acuminatum
Sand penstemon
Penstemon deustus
Hotrock penstemon
Penstemon speciosus
Royal or sagebrush penstemon
Lomatium dissectum
Fern leaf biscuitroot
Lomatium triternatum
Nine leaf desert parsley
Lomatium grayi
Gray's lomatium
Sphaeralcea coccinea
Scarlet Globemallow
Sphaeralcea grossulariifolia
Gooseberry Globemallow
Sphaeralcea parvifolia
Small flower Globemallow
Acnatherum thurberianum
Thurber’s needlegrass
Dalea ornata
Blue mountain prairie clover
Astralagus filipes
Basalt milkvetch
Cleome hassleriana
Spider flower, Pinkqueen
Crepis intermedia
Limestone Hawksbeard
Balsamorhiza sagittata
Arrowleaf balsamroot
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Powdery Mildew of Globe Mallow (red globe mallow) (Sphaeralcea coccinea)
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Powdery Mildew of Globemallow (Sphaeralcea coccinea)
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PM of Globemallow (gooseberry leaf)
(Sphaeralcea grossulariifolia)
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[Chasmothecia-Sexual fruit bodies]
Powdery mildew of Cleome hassleriana by Leveillula taurica
(Pink queen, Spider flower)
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PM on other hosts & weeds
Cleome lutea
Yellow beeplant
Cleome serrulata
Rocky Mountain
beeplant
Mentzelia laevicaulis
Giant blazing star
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Powdery mildew on Astragalus filipes
[basalt milkvetch]
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Powdery mildew on Cleome spp.[Spiderflower] and
Dalea ornata [prairie clover] by Leveillula taurica
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Co infection/Dual infection of Globemallow
[Sphaeralcea grossulariifolia] with Rust [Puccinia
sherardiana] and powdery mildew [Leveillula
taurica].
Rust spores
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Lomatium Rust-Puccinia jonesii
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Rust of Lomatium dissectumPuccinia jonesii
Rust spores
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Alternaria leaf blight of Lomatium
L. dissectum, L. triternatum and L. grayi
Alternaria Spores
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Leaf spot of Penstemon acuminatus by CMV [Cucumber Mosaic Virus]
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Leaf spot (Virus-CMV-Cucumber Mosaic Virus) of Penstemon acuminatus
(Sharpleaf penstemon, Sand-Dune Penstemon)
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Hollyhock Rust: Puccinia malvacearum
Host: Alcea rosea; others in Malvaceae
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Wilt of Stevia rebaudiana
[Pathogen-unknown]
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Leaf spot and blight of Veratrum californicum
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Enhancing Beneficial Insects with
Native Plants
• Bumble Bees
• Honey Bees
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Accomplishments:
 Several diseases [leaf spots, blights, rusts, wilts and
powdery mildews] were recorded on forbs.
 New and reemerging plant pathogens were noticed.
 Fungal, bacterial and viral diseases were recorded.
 Arid [hot and dry] conditions prevailing in PNW is
favorable for powdery mildew disease cycle [germination,
infection, production and release of generation/s of conidia ].
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Publications related to this study
• Sampangi, R.K, M.C. Aime. S. K. Mohan .and C.C.Shock.2010.
New and re-emerging rust diseases from Idaho and Oregon.
Phytopathology 100:S113
• Sampangi, R.K, M.C. Aime and S. K. Mohan. 2010. First Report
of Rust Caused by Puccinia similis on Artemisia tridentata in Idaho
and Oregon. Plant disease 94,380, 2010
[http://dx.doi.org/10.1094/PDIS-94-3-0380B]
• Sampangi, R. K. C. Almeyda, K. L. Druffel, S. K. Mohan, C.
C. Shock, and H. R. Pappu. 2009. First Report of Natural
Infection of Penstemon acuminatus with Cucumber mosaic virus in
the Treasure Valley Region of Idaho and Oregon. Plant Disease
93,762, 2009
• Sampangi, R.K, Glawe, D. A., and Mohan, S. K. 2007. First North
American record of powdery mildew of Cleome hassleriana
caused by Leveillula taurica. Online. Plant Health Progress
doi:10.1094/PHP-2007-02XX-01-BR.
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Questions ?
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Thank You
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Symptoms of PM on Onion
 Symptoms: sunken and bleached necrotic lesions with endophytic mycelium.
 No chasmothecia or sexual fruit bodies on Onions.
Discovery of the chasmothecia on several forbs suggests that it may contribute to genetic
variability of L. taurica in this region .
Diversity of crops with susceptible hosts & availability of inoculum source can often
leads to Increased potential for economic losses.
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Inoculum on forbs could play a role in overwintering of this pathogen in this region.
New disease/pathogen reports
New host –pathogen reports are vital in the quick
and accurate diagnosis of new plant diseases.
Helps improve our knowledge of biogeography,
pathogen biology and host range in the region.
New reports assist in establishing the baseline
information about any emerging plant diseases.
New reports also contribute to taxonomic studies,
including revision of species descriptions and
production of keys for identification.
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Unanswered questions?
Risk factors associated with these Plant pathogens:
 Pathogens/species invasive?: unknown
 Are they adaptable to different environments?:
unknown
 Do they have high reproductive potential?: unknown
 Can they survive winters ?can the inoculum remain
viable for more than one year?: unknown
 Increased host range/cross infectivity to other crops?
unknown
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