G Chemical

Nutritional Requirements

Watermelons have specific nutritional needs at different growth stages to ensure optimal yield and fruit quality.

Macronutrients:

• Nitrogen (N): Essential for leaf and vine growth (high requirement during vegetative stage)
• Phosphorus (P): Critical for root development and flowering
• Potassium (K): Vital for fruit quality, sweetness, and disease resistance

Micronutrients:

• Calcium: Prevents blossom end rot
• Magnesium: Essential for chlorophyll production
• Boron: Important for flowering and fruit set
• Zinc & Manganese: Required for enzyme activation

Fertilizer Program

Soil Preparation (Pre-planting)

• Organic Matter: 10-15 tons compost/acre
• Base Fertilizer: 10-10-10 or 15-15-15 @ 500-800 kg/acre
• Boron: 1-2 kg/acre (if soil is deficient)

Fertilizer Schedule

Common Watermelon Diseases & Solutions

Proper disease identification and management is crucial for successful watermelon cultivation.

Powdery Mildew

Causal Agent: Fungus (Podosphaera xanthii)

• White powdery spots on leaves and stems
• Yellowing and drying of leaves
• Reduced photosynthesis and yield
• Premature defoliation

• Apply sulfur-based fungicides early
• Use resistant varieties when available
• Ensure proper plant spacing for air circulation
• Apply Trifloxystrobin or Azoxystrobin fungicides

Anthracnose

Causal Agent: Fungus (Colletotrichum orbiculare)

• Dark, sunken lesions on leaves, stems, and fruits
• Circular spots with pinkish spore masses
• Fruit rot in storage
• Defoliation and plant death in severe cases

• Use disease-free seeds and transplants
• Apply Chlorothalonil or Mancozeb fungicides
• Practice 3-year crop rotation
• Remove and destroy infected plant debris

Fusarium Wilt

Causal Agent: Fungus (Fusarium oxysporum)

• Yellowing and wilting of leaves on one side
• Brown discoloration of vascular tissue
• Stunted growth and plant death
• More severe in warm soil conditions

• Use resistant varieties (e.g., 'Charleston Gray')
• Solarize soil before planting
• Practice long crop rotations (5-7 years)
• Apply biofungicides containing Trichoderma

Gummy Stem Blight

Causal Agent: Fungus (Stagonosporopsis cucurbitacearum)

• Brown lesions on stems with gummy exudate
• Circular spots on leaves with dark margins
• Fruit rot with black fungal structures
• Wilting and plant death in severe infections

• Apply Copper-based fungicides preventively
• Use clean, treated seeds
• Avoid overhead irrigation
• Apply Thiophanate-methyl or Azoxystrobin

Downy Mildew

Causal Agent: Fungus-like organism (Pseudoperonospora cubensis)

• Angular yellow spots on upper leaf surfaces
• Purple-gray mold on leaf undersides
• Rapid defoliation under favorable conditions
• Reduced fruit size and quality

• Apply Fosetyl-Al or Metalaxyl fungicides
• Improve air circulation with proper spacing
• Avoid overhead irrigation
• Use resistant varieties when available

Bacterial Fruit Blotch

Causal Agent: Bacteria (Acidovorax avenae subsp. citrulli)

• Water-soaked spots on fruit surfaces
• Cracking and brown corky lesions on fruits
• Leaf lesions with yellow halos
• Seedling damping-off in severe cases

• Use certified disease-free seeds
• Avoid working in fields when plants are wet
• Apply Copper bactericides preventively
• Practice 2-year crop rotation with non-cucurbits

Watermelon Growing Problems & Solutions

Insect Pests & Control

Major Insect Pests in Watermelon

Additional Recommended Insecticides

Integrated Pest Management (IPM)

Preventive Measures:

• Crop Rotation: Avoid planting cucurbits in same field for 2-3 years
• Clean Cultivation: Remove crop residues and weeds that host pests
• Healthy Seeds: Use certified, treated seeds
• Regular Monitoring: Weekly field scouting for early detection

Cultural Control:

• Trap Crops: Plant squash as trap crop for beetles
• Companion Planting: Marigolds repel nematodes
• Proper Spacing: 2m between rows, 1m between plants for air circulation
• Mulching: Plastic mulch reduces weed and pest pressure

Biological Control:

• Ladybugs: Natural predators of aphids
• Trichogramma Wasps: Parasitize caterpillar eggs
• Beauveria bassiana: Fungus that controls sucking pests

G Chemical Products Recommendation

For effective pest and disease control in watermelon cultivation, consider these products from our catalog:

Fungicides for Disease Control:

• Propiconazole 95% TC, 250g/L EC - Systemic fungicide for powdery mildew
• Pyraclostrobin 97.5% TC, 25% SC - Broad-spectrum fungicide
• Difenoconazole 98.5% TC, 10% WG - Effective against anthracnose and gummy stem blight
• Carbendazim 98% TC, 50% WP - Systemic fungicide for various diseases
• Thiophanate-methyl 95% TC, 50% WP - Broad-spectrum fungicide

Insecticides for Pest Control:

• Imidacloprid 97% TC, 70% WP - Systemic insecticide for sucking pests
• Lambda-cyhalothrin 95% TC, 25% WP - Broad-spectrum insecticide
• Acetamiprid 99% TC, 3% EC - Effective against aphids and whiteflies
• Deltamethrin 98.5% TC, 2.5% EC - Pyrethroid for chewing insects
• Hexaflumuron 95% TC, 5% EC - Insect growth regulator for mites