Integrated Pest Management in Watermelon

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Integrated Pest Management in Watermelon

• Camilla B. Yandoc

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Watermelon Pests

• Insects Mites
• Weeds
• Diseases
• Nematodes

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Common Insect Pests
Rindworms
Sweetpotato whitefly
Aphids

• Cutworms

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Aphids Whiteflies

• Downward curling crumpling of leaves (aphids)
• Honeydew excreted by both insects attracts sooty
  molds
• Both are efficient vectors of plant viruses

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Cutworms Rindworms

• Cutworms reduce young watermelon stands
• May feed on leaves of young seedlings
• Rindworms general term for worms that feed on
  rind (fall armyworms, corn earworm, cutwroms and
  loopers
• Foliage stem damage
• Eat away irregular patterns of the rind

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Occasional Insect Pests

• Cucumber beetle
• Mites
• Mole crickets
• Wireworms
• White-fringed beetle
• Leafminers
• Thrips

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Occasional Insect Pests

• Root maggots
• Flea beetles fleahoppers
• Leafhoppers
• Plant bugs
• Grasshoppers
• Melonworms pickleworms

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Insect Damage

• Foliar damage (holes)
• Stem damage
• Root damage (wilting, stunting death of plant)
• Fruit damage
• Drying up of leaves (sucking insects)
• Leaf spots, mottling or discoloration

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Insect Mite Management
Important Practices

• Sampling
• Establish ETL
• Recognize identify beneficials

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Aphid Control

• Biocontrol
• lady beetles, syphrid fly
• larvae,lacewings tiny wasps
• cultural control
• reflective plastic mulch
• Stylet oil sprays (interferes
• with virus transmission)

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Sweetpotato Whitefly Control

• Monitoring use of traps
• Cultural control
• planting location sanitation
• Weed control
• control alternate hosts
• Chemical control
• alternate different classes of
• insecticides

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Cutworm Rindworm Control

• Mechanical control (cutworm) thorough soil prep
• Chemical control(cutworm) broadcast application
  of approved insecticides before planting
• Chemical control(rindworm) spray before worms gt
  1/2 in length, spray all of exposed fruit

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Control of Other Insect Pests

• Chemical control
• insecticide sprays for flea
• beetles, leafminers, mites,
• mole crickets,wireworms,
• fleahoppers,leafhoppers,
• plant bugs,grasshoppers, melon
• worms and pickleworms

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Control of Other Insect Pests

• Cultural control
• avoidance (white-fringed
• beetles), plowing deep
• turning of crop litter before
• planting (root maggots),
• overhead irrigation (mites)

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Insect Mite Management
Cultural Practices

• Reflective mulch
• Planting location/timing
• Sanitation
• Weed control
• Overhead irrigation
• Plowing turning in crop debris

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Diseases

• Reduce crop yield quality
• Poor disease control due to delayed accurate
  diagnosis delayed implementation of control
  measures
• Disease control consists of a sequence of
  properly timed control measures (cultural,
  mechanical chemical)

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Root Stem Diseases

• Gummy stem blight

• Fusarium rot

• Anthracnose
• Damping-off

• Fusarium wilt

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Root Stem Disease Management

• Gummy stem blight postharvest plow-down of
  debris, crop rotation, fungicidal sprays, use
  fungicide treated seeds
• Anthracnose resistant varieties, fungicidal
  sprays, clean seeds,sanitation
• Fusarium wilt resistant var.,healthy
  transplants,crop rotation, soil fumigation,
  delayed thinning

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Foliar Diseases
Anthracnose
Cercospora leaf spot
Downy mildew
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Other Foliar Diseases

• Alternaria leaf spot
• Bacterial leaf spot
• Watermelon mosaic

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Foliar Disease Management

• Cercospora leaf spot sanitation (removal of crop
  debris, diseased vines weed hosts), crop
  rotation, fungicide sprays
• Downy mildew fungicide application, resistant
  var., avoid irrigation, reduce canopy density

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Foliar Disease Management

• Alternaria leaf spot
• protectant fungicides
• Bacterial leaf spot
• avoid overhead irrigation,
• sanitation, protective sprays
• (copper sprays)

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Foliar Disease Management

• Watermelon mosaic
• stylet oil application to
• interfere with virus
• transmission insecticides to
• control aphid (vector)population

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Fruit Diseases
Anthracnose
Bacterial rind necrosis
Bacterial fruit blotch
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Other Fruit Diseases

• Bacterial leaf spot
• Blossom-end rot
• Speckle
• Watermelon mosaic

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Fruit Disease Management

• Bacterial fruit blotch
• plowing infested soil,
• elimination of inoculum
• sources, field rotated out for
• 3 years or more, copper
• sprays (Kocide DF Kocide 2000),
• use of high quality transplants

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Fruit Disease Management

• Anthracnose
• resistant varieties,
• fungicides, use clean seeds
• Bacterial rind necrosis
• use less susceptible cultivars

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Fruit Disease Management

• Blossom end-rot
• soil testing liming,
• irrigation during fruit
• development (preventive),
• foliar Calcium application
• (curative)

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Disease Management
Cultural Practices

• Sanitation
• Healthy transplants
• Resistant varieties
• Crop rotation
• Weed/Insect vector control
• Liming irrigation

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Disease Management
Chemical Control

• Fungicide sprays
• Soil fumigation
• Fungicide seed treatment

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Weeds

• Compete with the crop for nutrients, sunlight,
  water and space
• Serve as alternate hosts of nematodes, viruses
  and insect pests

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Weed Management
Cultural, Mechanical Chemical Control

• Polyethylene mulch
• Cultivation
• Soil fumigant
• Hoeing disking
• Herbicides

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Economically Important Nematodes

• Root-knot nematodes (Meloidogyne spp.)
• Sting nematode (Belonolaimus longicaudatus)
• Reniform nematode (Rotylenchus sp.)

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Nematode Damage

• Root galls interfere with normal water nutrient
  uptake
• Reduced size of root system limits availability
  of water nutrients
• Aboveground damage stunting, wilting chlorosis
• Roots attacked by nematodes are predisposed to
  secondary invasion by root rotting plant
  pathogens

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Nematode Management
Cultural Practices

• Planting location
• Resistant varieties
• Crop rotation
• Land preparation
• Use of clean healthy transplants

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Nematode Management
Chemical Control

• Fumigants
• Non-fumigants
• Chemigation

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A Growers Pest Management Tactics

• Insect control chemical insecticides
• Weed control mechanical control (cultivation)
• Disease control resistant varieties chemical
  fungicides, removal destruction of diseased
  seedlings

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What Growers Do in the Field

• Scout for presence of insects and diseases (major
  pest problem)
• Watch the weather and spray accordingly (follow
  recommendations)
• Some spray protective fungicides even when
  weather is dry (for insurance)

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What Growers Do in the Field..

• May spray 1 or 2x a season for aphid control,
  some never spray because insect problem is minor
• Follow recommendations for tillage crop
  rotation
• Plant in soils without RKN problems

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What Growers do in the Field

• Fusarium Wilt control crop rotation, use of
  resistant varieties, scouting for diseased
  transplants and removal of infected transplants
• Gummy stem blight Downy mildew control
  fungicide sprays based on weather(likelihood of
  disease occurrence) or presence of spots

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References

• Zitter, A.T., D.L. Hopkins, and C.E. Thomas
  (eds.). 1996. Compendium of Cucurbits Diseases.
  APS Press.
• Maynard, D. N. (ed.). 1992. Watermelon
  Production Guide for Florida. Florida Cooperative
  Extension Service IFAS
• Mr. Melvin Poole (Gainesville watermelon grower)
• Mr. Gerry Brinen (County Extension Office)