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: 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 balsamroot3

Powdery Mildew of Globe Mallow (red globe mallow) (Sphaeralcea coccinea)

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Powdery Mildew of Globemallow (Sphaeralcea coccinea) 5

PM of Globemallow (gooseberry leaf)(Sphaeralcea grossulariifolia) 6

Powdery mildew of Cleome hassleriana by Leveillula taurica(Pink queen, Spider flower) 7

[Chasmothecia-Sexual fruit bodies]

PM on other hosts & weeds

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Cleome luteaYellow beeplant

Cleome serrulataRocky Mountain beeplant Mentzelia laevicaulis

Giant blazing star

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].

11Rust spores

Lomatium Rust-Puccinia jonesii

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Rust of Lomatium dissectum-Puccinia jonesii

13Rust spores

Alternaria leaf blight of Lomatium

14Alternaria SporesL. dissectum, L. triternatum and L. grayi

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) 16

Hollyhock Rust: Puccinia malvacearumHost: Alcea rosea; others in Malvaceae 17

Wilt of Stevia rebaudiana[Pathogen-unknown]

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Leaf spot and blight of Veratrum californicum19

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 hasslerianacaused 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.

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?: unknownAre they adaptable to different environments?:

unknownDo they have high reproductive potential?: unknownCan they survive winters ?can the inoculum remain

viable for more than one year?: unknown Increased host range/cross infectivity to other crops?

unknown