Pulse and Forage Diseases

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Pulse and Forage Diseases

• Dr. Mary Burrows
• Montana State University Bozeman, MT

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Bacterial blight of pea
Angular lesions
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Ascochyta blight on pea and chickpea
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Fusarium root rot of pea
Fusarium solani f.sp. pisi
Constriction
Reddish-brown
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Fusarium wilt of pea
Fusarium oxysporum f.sp. pisi

• Resistant varieties
• Seed treatment
• Rotation

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Crown rot symptoms in alfalfa
Verticillium, Fusarium, Rhizoctonia,
Phytophthora, Pythium, Phoma, Mycoleptodiscus,
Stagonospora, and Macrophomina
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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

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Stem nematode in alfalfa

• Ditylenchus dipsaci

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

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Boron deficiency in alfalfa

• Can result in hollow, corky stems bushy plant
  yellow/reddish leaves
• Test soil apply fertilizer containing boron

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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

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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

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Ergot history (rye)

• 400 B.C. Hippocrates prescribed ergoty grain to
  further childbirth
• 1039 St. Anthonys fire
• 1692 Salem witch trials
• 1935 LSD was synthesized during research on the
  active ingredients in ergot
• Ergot contains Lysergic acid

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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

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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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Samples must contain the right material an
entire plant or several plants if practical
Diseases may show up on any part of the plant.
Foliage diseases
Keep most roots and soil intact if possible
Check for injuries, disease on the main stem/trunk
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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
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Actual 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
Sample soup
Dont add water or wrap in wet paper towels
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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.

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http//diagnostics.montana.edu

• Click on
• Plant
• Diseases

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• Click on
• Disease Diagnosis Form

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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

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Include photographs illustrating the problem and
field patterns if possible.
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Communication resources

• AgAlerts PDIS.org, or contact Linnea Skoglund
  (994-5150 or diagnostics_at_montana.edu)
• Montana Ag Fax Fax request to
• 406-994-7600 or send an e-mail to
  mburrows_at_montana.edu

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Wiki.bugwood.org/HPIPM
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Be a First Detector
First Detectors are the front line for early
discovery of new invasive pests.
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What is a high risk pest/pathogen?

• A pest not currently known to occur in the
  continental United States exotic

Southern bacterial wilt Ralstonia solanacearum
A pest with limited distribution in the
continental United States, but economically
important if it spreads.
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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)

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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

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response
diagnosis
detection
What happens when a high risk pest is found?
APHIS SDAs
APHIS
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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

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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/inde
  xag.html
• Wheat diseases of Montana
• http//scarab.msu.montana.edu/Disease/DiseaseGuid
  ehtml/

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Forage Crop Diseases

• Disease triangle
• Best management practices
• Expected yield hit
• What factors would favor/disfavor disease

Host
Pathogen
Environment