Transplant Diseases and their Management

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Transplant Diseasesand their Management
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Take Healthy Plants to the Field

• More vigorous tolerant of stress
• Less likely to cause outbreaks of disease in the
  field
• Less likely to get unrelated diseases
• Black shank
• Fusarium wilt

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Prevention is an important consideration in
managing diseases in a float bed
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How Pathogens Enter the Float System

• Air
• Water
• Contaminated plants, soil, trays, equipment
• People animals
• Insects

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Integrated Approach toDisease Management

• Pathogen
• Sanitation
• Fungicides
• Environment
• Temperature
• Moisture
• Host
• Temperature
• Injury
• Stress

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Sanitation

• Clean transplant trays are critical to success
• Pythium Rhizoctonia will carry over in old
  trays
• Key to managing Pythium target spot
  (Rhizoctonia)
• Keep soil out of bays
• Source of pathogens like Pythium and Rhizoctonia
• Keep diseased plants out of the float system
• Pythium root rot
• Blue mold

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Sanitation as a Tool for Disease Management

• Control weeds in and around float systems
• Keep diseased plants out of your system
• Imported tobacco seedlings

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Sanitation as a Tool for Disease Management

• Finish clean!
• Destroy unused transplants as quickly as possible
• Clean store trays
• Source of blue mold after transplanting

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Promote Rapid Drying of Leaves

• Adequate ventilation side vents, fans
• Proper location of beds greenhouses
• Proper level of water in beds
• Manage weeds

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Minimize Plant Stress

• Maintain proper fertility level
• Excess nitrogen favors black leg, blue mold,
  collar rot
• Nitrogen deficiency favors target spot
• Prevent injury to plants
• Heat stress
• Cold stress

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Clipping

• Avoid stress buildup of plant debris
• Clip properly minimize injury stress
• Remove clippings and dispose of them properly
• Clean and sanitize equipment after each use

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Pythium Root Rot
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Management of Pythium Root Rot

• Sanitation
• Terramaster 4EC
• PREVENTIVE 1 fl oz/100 gal _at_ 2-3 weeks after
  seeding (when roots enter water)
• 2nd application _at_ 1 fl oz 3 weeks later
• Final applicaton _at_ 0.8 fl oz 2 weeks after 2nd
  app.
• CURATIVE 1.4 fl oz/100 gal no sooner than 3
  weeks after seeding
• 2nd application can be made at 1-1.4 fl oz/100
  gal 3 weeks after 1st application

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Target spot (Rhizoctonia solani)
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Target spot
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Rhizoctonia damping-off
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Sclerotinia collar rot
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Black Leg(Erwinia caratovora)
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Management of Leaf and Stem Diseases

• Sanitation exclusion of contaminated plants
• Minimize leaf wetness
• Clip properly manage temperatures
• Avoid buildup of leaf debris
• Maintain proper nitrogen level
• 100 ppm for as long as recommended
• Fungicides
• Preventive or at 1st symptoms
• Good coverage is important for good control

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Chemicals for Control of Leaf Diseases on
Seedlings

• Dithane DF
• Blue mold, anthracnose, damping-off
• 0.5 lb/100 gal of spray water (1 level tsp/gal)
• Apply 3-12 gallons per 1000 sq. ft
• Continue on a 5-day schedule until transplanting
• Aliette WDG
• Blue mold only
• 0.5 lb/50 gal of spray water (2 level tsp/gal)
• AgriMycin-17 (Agricultural streptomycin)
• Blackleg / bacterial soft rot (suppression)
• 100-200 ppm (1-2 level tsp/gal of spray water)