Transcript MSU key messages

Pulse and Forage Diseases
Dr. Mary Burrows
Montana State University Bozeman, MT
Bacterial blight of pea
Angular lesions
Ascochyta blight on pea and
chickpea
Fusarium root rot of pea
Fusarium solani f.sp. pisi
Constriction
Reddish-brown
Fusarium wilt of pea
Fusarium oxysporum f.sp. pisi
• Resistant varieties
• Seed treatment
• Rotation
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
Swollen nodes
Stunted plants, shortened internodes
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 animals
4 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 symptoms
depend 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
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
Foliage diseases
Keep most roots and soil
intact if possible
Diseases may
show up on any
part of the plant.
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
19
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
Don’t 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’
Click on
‘Disease
Diagnosis
Form’
Disease Diagnosis Form
• Print out form
• Fill out questionnaire 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
Southern bacterial wilt
Ralstonia solanacearum
Asian long-horned beetle
Anoplophora glabripennis (Motschulsky)
A pest with limited
distribution in the
continental United States,
but economically
important if it spreads.
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
detection
diagnosis
response
What
happens whenExpert
a high risk pest
FD
SPRO/SPHD
NPDN lab
is found?
lab
FD
NPDN
APHIS
APHIS
& SDAs
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/p
p622/pp622.pdf
• MontGuides:
http://www.montana.edu/wwwpb/pubs/indexa
g.html
• Wheat diseases of Montana
http://scarab.msu.montana.edu/Disease/Dise
aseGuidehtml/
Forage Crop Diseases
•
•
•
•
Disease triangle
Best management practices
Expected yield hit
What factors would favor/disfavor
disease
Host
Pathogen
Environment