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Pulse and Forage Diseases Dr. Mary Burrows Montana State University Bozeman, MT

Pulse and Forage Diseases Dr. Mary Burrows Montana State University Bozeman, MT

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Pulse and Forage Diseases

Dr. Mary BurrowsMontana State University

Bozeman, MT

Bacterial blight of pea

Angular lesions

Fusarium root rot of peaFusarium solani f.sp. pisi

Constriction

Reddish-brown

Fusarium wilt of pea

• Resistant varieties• Seed treatment• Rotation

Fusarium oxysporum f.sp. pisi

Crown rot symptoms in alfalfa

Verticillium, Fusarium, Rhizoctonia, Phytophthora, Pythium, Phoma, Mycoleptodiscus, Stagonospora, and Macrophomina

Crown rot control• Variety selection• Promote vigorous growth with proper fertility and

irrigation practices.• Control foliar diseases and insect problems.• Avoid cutting hay when soils are wet.• Avoid heavy grazing.• Control weeds with herbicides and avoid cultivation

practices which damage crowns.• Avoid field sites with heavy or poorly-drained soils.• Rotate out of alfalfa for 2-3 years.• Heavy watering in the fall will delay dormancy

– Stop watering end of September

Stem nematode in alfalfa• Ditylenchus dipsaci

White flagging Stunted plants, shortened internodesSwollen nodes Crinkled leaves (between veins)

Stem nematode on alfalfa• Spread by surface water runoff, irrigation,

wind-blown crop debris, infested hay, soil and crop debris clinging to equipment, humans and livestock, and with seed

• Prevent introduction of nematodes into a field• Rotate with a non-host (not alfalfa or sainfoin)

and control alfalfa volunteers 2-4 years• Some resistant lines (not completely resistant)• Cut infected fields slightly higher and when dry

to reduce spread

Boron deficiency in alfalfa• Can result in hollow, corky stems;

bushy plant; yellow/reddish leaves

• Test soil; apply fertilizer containing boron

Alfalfa mosaic virus

• Vectored by aphids

• Symptoms masked by heat

• Wide host range: most legumes, many weeds, potatoes

• Transmitted mechanically and in seed

• Makes plants more susceptible to winterkill

Ergot in grasses used for feed/forage

• Calviceps purpurea• Sclerotia contaminate seed• Soilborne sclerotia overwinter; viable approximately 3 yr in soil or longer in stored grain• Ascospores dispersed by wind and rain infect

florets; conidia formed on ovary surface serve as secondary inoculum

• Grain converted into sclerotia• More abundant during moist growing seasons

Ergot history (rye)• 400 B.C. Hippocrates prescribed ergoty

grain to “further childbirth”• 1039 St. Anthony’s fire• 1692 Salem witch trials• 1935 LSD was synthesized during

research on the active ingredients in ergot– Ergot contains Lysergic acid

Ergoty grain is toxic to animals4 forms of toxicity

• Convulsions• Gangrene• Hyperthermia (increased body temperature)

in cattle• Agalactia (no milk) and lack of mammary

gland development, prolonged gestations, and early foal deaths in mares fed heavily contaminated feed

Ergot toxicity symptomsdepend on:

• Type of ergot consumed • Ratio of major toxic alkaloids present in the

ergot: ergotamine, ergotoxine, and ergometrine

• Frequency and quantity of ingestion• Climactic conditions when ergot was growing• Species of ergot• Other impurities in the grain such as

histamine and acetylcholine• Claviceps purpurea is usually associated with

gangrenous ergotism

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Sample Submission• Accurate Diagnosis depends on a

good sample and symptom description

Enter sample information into PDIS (Plant Diagnostic Information System)

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Foliage diseases

Check for injuries, disease on the main stem/trunk

Keep most roots and soil intact if possible

Samples must contain the right material: an entire plant or several plants if practical

Diseases may show up on any part of the plant.

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Dead Plants Tell no Tales

Avoid dead plants Choose plants which show a

range of symptoms: moderate to severe

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Packaging & Shipping

Good Intentions

20Actual Results

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Packaging and Shipping blunders

Soil on foliage during shipping creates “diseases” that were not there when the sample was collected.

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Packaging and shipping blunders

Don’t add water or wrap in wet paper towels

Sample soup

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Good Packaging

Plastic bag to keep soil on roots Dry paper towels to protect leaves

from contact with plastic bag

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Sample Submission

• Try to keep sample as fresh as possible until you can get it to the county agent: refrigerate if possible.

• Include photographs illustrating the problem if possible.

http://diagnostics.montana.edu

Click on

‘Plant

Diseases’

Click on

‘Disease Diagnosis Form’

Disease Diagnosis Form

• Print out form• Fill out question-

naire with as much detail as possible

• Place form in box with sample

• Take to County Agent – If Possible

Include photographs illustrating the problem and field patterns if possible.

Communication resources

• AgAlerts: PDIS.org, or contact Linnea Skoglund (994-5150 or [email protected])

• Montana Ag Fax: Fax request to

406-994-7600 or send an e-mail to [email protected]

Wiki.bugwood.org/HPIPM

Be a First Detector

First Detectors are the front line for early discovery of new invasive pests.

What is a high risk pest/pathogen? A pest not currently

known to occur in the continental United States = exotic

Asian long-horned beetleAnoplophora glabripennis (Motschulsky)

A pest with limited distribution in the continental United States, but economically important if it spreads.

Southern bacterial wiltRalstonia solanacearum

Select Agents

• Liberobacter africanus, Liberobacter asiaticus (Citrus greening)

• Peronosclerospora philippinensis (Philippine downy mildew )

• Ralstonia solanacearum, race 3, biovar 2 (Southern wilt)

• Sclerophthora rayssiae var. zeae (Brown stripe downy mildew )

• Synchytrium endobioticum (Potato wart disease)• Xanthomonas oryzae pv. Oryzicola (Rice leaf streak)• Xylella fastidiosa (citrus variegated chlorosis

strain)

High Consequence Pests (diseases) of Concern for Great Plains region

(some examples)

• Wheat: karnal bunt, rice blast, seed gall nematode

• Potato: potato wart, golden nematode, pale cyst nematode, potato rot nematode, phytoplasmas, wilt

• Stone fruits: plum pox virus

diagnosis responsedetection

NPDN lab Expertlab

NPDN APHISAPHIS& SDAs

FD

FDSPRO/SPHD

What happens when a high risk pest What happens when a high risk pest is found?is found?

Your role as a First Detector• Receive NPDN First Detector training

• Take online modules (http://cbc.at.ufl.edu)• Attend classes like this one

• Be alert to the unusual or different• Know how to properly submit a suspect high risk

pest or pathogen sample • Know how to maintain chain of custody and

communication when submitting a suspect sample

• Be placed on a national notification registry of First Detectors if you wish to

• Receive pest alerts and other relevant updates

Informational sites• Highplainsipm.org• Greenbook.net: Pesticide labels• NDSU fungicide guide

http://www.ag.ndsu.edu/pubs/plantsci/pests/pp622/pp622.pdf

• MontGuides: http://www.montana.edu/wwwpb/pubs/indexag.html

• Wheat diseases of Montanahttp://scarab.msu.montana.edu/Disease/DiseaseGuidehtml/

Forage Crop Diseases• Disease triangle

• Best management practices

• Expected yield hit

• What factors would favor/disfavor disease Host

Pathogen Environment