Dwight K. Jesseman

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Dwight K. Jesseman

• St. Johns County
• Agricultural Agent

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Nematology

• Basic Principles for Master Gardeners

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Types of Nematodes

• Plant Parasitic
• Predatory
• Entomophagous
• Free Living
• Marine

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Plant Parasitic
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Predatory
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Entomophagous
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Free Living
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Marine
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Morphology and Anatomy

• Animals
• Round Worms
• Size 0.25mm to 3.0mm
• Layered Cuticle
• Vermiform, Globose, Kidney Shaped

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Layered Cuticle
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Vermiform
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Globose
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Kidney Shaped
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Life Cycle and Reproduction

• Egg - 50 to 500
• Four Juvenile Stages
• Adult
• Male and Female in Most Species
• Life Cycle Dependant on Soil Temperatures
• Move Slowly

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Egg and Juvenile
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Feeding

• Oral Stylet or Spear
• Inject Enzymes
• Digest Cell Contents

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Oral Stylet
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Host- Parasite Relationship

• Migratory Ectoparasitic
• Ring, Spiral
• Migratory Endoparasitic
• Lesion, Burrowing
• Sedentary Endoparasitic
• Root-Knot, Cyst, Reniform, Citrus

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Migratory Ectoparasitic
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Migratory Endoparasitic
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Sedentary Endoparasitic
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Diagnoses

• Very Difficult at Times
• Poor Growth
• Combination of Problems
• Assay of Soil and/or Plant Tissue
• Symptoms

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Above-Ground

• Rarely Sufficient
• Chlorosis
• Dieback
• Melting out
• Reduced Growth
• Water Stressed

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Reduced Growth
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Below-Ground

• Root Galls
• Root Swellings
• Abbreviated Root System
• Root Rot
• Cyst Nematodes

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Root Galls
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Abbreviated Root System
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Cyst Nematodes
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Field History

• Gradual Decline
• Area - Small to Large
• Rotation of Crops

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Laboratory Assay

• Soil and Plant Tissue
• Relative Population Densities
• Economic Thresholds

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Nematode Management

• Prevention
• Crop Rotation
• Crop Root Destruction
• Flooding and Fallowing
• Resistance
• Biological Control
• Nematicides

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Home Garden

• Container Growing
• Site Selection
• Crop Rotation
• Soil Tillage and Root Destruction
• Amendments
• Organic Matter
• Green Manures

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Home Garden

• Planting Time
• Nematode - Free Transplants
• Resistant Varieties
• Soil Solarization
• Chemical Control

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Soil Solarization

• Cover for at least 4 weeks
• Well Tilled
• High Moisture
• Slightly Raised Beds
• Crown the Bed

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Soil Solarization

• Clear Polyethylene
• Thin Plastic 1 to 2 mil
• Leave in Place Until Planting
• Avoid Contaminated Plants or Soil

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Soil Temperatures

• Tarped Soils 111 to 122
• 115 - Water Molds
• 120 - Nematodes
• 140 - Most Fungi
• 150 - Most Soil Insects
• 160 - Most Viruses and Bacteria
• 170 - Most Weed Seeds

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Ornamentals

• Site Preparation
• Treat Soil
• Fumigation
• Soil Solarazition
• Replace Infested Soil
• Root Barriers

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Ornamentals

• Nematode-Free Stock
• Well Adapted Plants
• Resistant Plants
• Maintenance
• Mulches
• Other Pests
• Chemical Control

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Turf

• Biological Controls
• Resistant Plants
• Chemical Control
• Fumigation Before Planting

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Resistance

• Bahiagrasses - Tolerant of Most
• Centipedegrasses - Ring, Sting, Sheath
• St. Augustinegrasses -Sting, Lance
• Bermudagrasses - Sting, Lance, Stubby
• Zoysiagrasses - Most nematodes

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Basimid Granular Use

• Compost Piles
• Potting Soils
• Seed and Propagation Beds
• Soil Media
• Establishing Turf and Ornamental Sites
• Not for Use in Vegetable Gardens
• READ THE LABEL, IT IS THE LAW

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Questions