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Bacterial blight of pea
Angular lesions
Ascochyta blight on pea and chickpea
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
16
Sample Submission• Accurate Diagnosis depends on a
good sample and symptom description
Enter sample information into PDIS (Plant Diagnostic Information System)
17
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
21
Packaging and Shipping blunders
Soil on foliage during shipping creates “diseases” that were not there when the sample was collected.
23
Good Packaging
Plastic bag to keep soil on roots Dry paper towels to protect leaves
from contact with plastic bag
24
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.
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
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]
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/