Major Pests and Diseases of Grapes and Their Integrated Management

Major Pests and Diseases of Grapes and Their Integrated Management

Introduction

Grapes (Vitis vinifera L.) is one of the most economically important fruit crops in India, cultivated extensively in Maharashtra, Karnataka, Telangana, Andhra Pradesh, and Tamil Nadu. While grapes offer high returns, they are also highly sensitive to pest and disease pressure, especially under warm and humid conditions.

Improper pest and disease management can cause 30–70% yield loss, reduce fruit quality, and severely affect export potential. Hence, Integrated Pest and Disease Management (IPDM) is the key to sustainable grape production.

MAJOR INSECT PESTS OF GRAPES

1. Grape Thrips (Rhipiphorothrips cruentatus)

Symptoms

  • Silvery streaks on young leaves
  • Leaf curling and distortion
  • Flower drop during severe infestation
  • Poor berry development

Favourable Conditions

  • Hot and dry weather
  • Dense canopy with poor aeration

Management

Cultural:

  • Maintain proper pruning and canopy management
  • Avoid excess nitrogen fertilization

Biological:

  • Encourage natural predators like Chrysoperla

Chemical:

  • Spinosad 45 SC @ 0.3 ml/L
  • Emamectin benzoate 5 SG @ 0.4 g/L

Organic option:

  • Neem oil 3 ml/L or Azadirachtin 1500 ppm

2. Flea Beetle (Scelodonta strigicollis)

Symptoms

  • Holes on newly emerged buds
  • Damage to tender shoots and flowers
  • Reduced fruit set

Management

Cultural:

  • Clean cultivation after pruning

Mechanical:

  • Early morning shaking of vines

Chemical:

  • Imidacloprid 17.8 SL @ 0.3 ml/L
  • Thiamethoxam 25 WG @ 0.25 g/L

3. Mealybugs (Planococcus citri)

Symptoms

  • White cottony masses on shoots, leaves, and bunches
  • Honeydew secretion leading to sooty mold
  • Weak vines and poor berry quality

Management

Cultural:

  • Destroy infested plant parts
  • Control ants using sticky bands

Biological:

  • Release Cryptolaemus montrouzieri

Chemical:

  • Buprofezin 25 SC @ 1 ml/L
  • Chlorpyriphos 20 EC @ 2.5 ml/L (soil drenching)

Organic:

  • Fish oil rosin soap @ 5 ml/L

Dr. Eliminator: https://www.khethari.com/products/dr-eliminator-insecticide?_pos=1&_sid=b715ea90c&_ss=r

 

4. Stem Girdler (Sthenias grisator)

Symptoms

  • Girdling of shoots
  • Sudden drying of canes
  • Reduced vine vigor

Management

  • Remove and destroy affected canes
  • Spray Quinalphos 25 EC @ 2 ml/L during adult emergence

MAJOR DISEASES OF GRAPES

1. Downy Mildew (Plasmopara viticola)

Symptoms

  • Yellow oil spots on upper leaf surface
  • White cottony growth on lower surface
  • Severe leaf drop and berry rot

Favourable Conditions

  • High humidity (>85%)
  • Rainfall and cloudy weather

Management

Cultural:

  • Proper spacing and air circulation

Chemical:

  • Metalaxyl + Mancozeb @ 2 g/L
  • Cymoxanil + Mancozeb @ 2 g/L

Preventive spray:

  • Bordeaux mixture 1%

2. Powdery Mildew (Uncinula necator)

Symptoms

  • White powdery coating on leaves, shoots, and berries
  • Cracking of berries
  • Reduced sugar content

Favourable Conditions

  • Warm (25–30°C) and dry climate

Management

Cultural:

  • Avoid excessive shading

Chemical:

  • Wettable sulfur @ 2 g/L
  • Hexaconazole 5 EC @ 1 ml/L

Resistance management:

  • Rotate fungicides with different modes of action

3. Anthracnose (Elsinoe ampelina)

Symptoms

  • Dark sunken lesions on leaves and berries
  • “Bird’s eye” spots on fruits
  • Reduced market value

Management

  • Prune and destroy infected parts
  • Spray Carbendazim 1 g/L or Chlorothalonil 2 g/L

4. Botrytis Bunch Rot (Botrytis cinerea)

Symptoms

  • Gray mold on berries
  • Soft rot during storage and transport
  • Major issue in export grapes

Management

  • Avoid overhead irrigation
  • Spray Iprodione 50 WP @ 2 g/L
  • Maintain bunch hygiene

5. Bacterial Leaf Spot (Xanthomonas campestris)

Symptoms

  • Small angular leaf spots
  • Leaf yellowing and premature drop

Management

  • Copper oxychloride @ 3 g/L
  • Avoid injury during pruning

INTEGRATED PEST & DISEASE MANAGEMENT (IPDM) STRATEGY

Key IPDM Practices

  • Selection of disease-free planting material
  • Regular field scouting
  • Pruning sanitation
  • Balanced nutrition
  • Timely fungicide and insecticide rotation
  • Use of biological agents and botanicals
  • Weather-based disease forecasting

Conclusion

Grape cultivation is both an art and a science. With increasing climate variability, pest and disease pressure is rising every year. Farmers who adopt preventive, integrated, and timely management practices not only reduce losses but also achieve better quality, higher yields, and improved profitability.

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