PEST AND DISEASES IN KIWI AND THEIR MANAGEMENT
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Major Pests and Diseases of Kiwi and Their Management
Introduction
Kiwi (Actinidia deliciosa) is a high-value temperate fruit crop known for its excellent nutritional value and market demand. However, kiwi vines are susceptible to several insect pests and diseases that can reduce plant vigor, fruit quality, and yield. Proper orchard sanitation, regular monitoring, and Integrated Pest Management (IPM) practices are essential to maintain healthy vines and achieve higher productivity.
Major Insect Pests of Kiwi
1. Scale Insects
Scientific name: Hemiberlesia rapax, Pseudaulacaspis pentagona
Symptoms
- Small, hard, shell-like insects on stems, leaves, and fruits.
- Sap sucking weakens vines.
- Yellowing and premature leaf fall.
- Poor fruit quality due to blemishes.
Management
- Prune and destroy heavily infested branches.
- Encourage natural predators such as ladybird beetles.
- Spray horticultural mineral oil during dormant season.
- If infestation is severe, spray Imidacloprid 17.8 SL @ 0.3 ml/L or Thiamethoxam 25 WG @ 0.25 g/L.
2. Leaf Roller
Scientific name: Ctenopseustis obliquana and related species
Symptoms
- Caterpillars roll leaves using silk.
- Feed on leaves, flowers, and young fruits.
- Fruits develop feeding scars and deformities.
Management
- Remove rolled leaves manually.
- Install pheromone traps for monitoring.
- Spray Emamectin Benzoate 5 SG @ 0.4 g/L or Spinosad 45 SC @ 0.3 ml/L.
3. Two-Spotted Spider Mite
Scientific name: Tetranychus urticae
Symptoms
- Tiny mites feed on leaf undersides.
- Yellow stippling on leaves.
- Fine webbing on foliage.
- Reduced photosynthesis and fruit size.
Management
- Maintain adequate irrigation.
- Avoid excessive nitrogen fertilizer.
- Spray Abamectin 1.9 EC @ 0.5 ml/L or Spiromesifen 22.9 SC @ 1 ml/L.
4. Thrips
Symptoms
- Silver streaks on leaves.
- Scarring on fruits.
- Poor fruit appearance and reduced market value.
Management
- Install blue sticky traps.
- Maintain weed-free orchards.
- Spray Spinetoram 11.7 SC @ 0.5 ml/L or Fipronil 5 SC @ 1 ml/L.
5. Mealybugs
Symptoms
- White cotton-like insects on shoots and fruits.
- Honeydew secretion leading to sooty mold.
- Reduced plant vigor.
Management
- Remove alternate host weeds.
- Release predatory ladybird beetles.
- Spray Buprofezin 25 SC @ 1 ml/L or Imidacloprid 17.8 SL @ 0.3 ml/L.
Major Diseases of Kiwi
1. Bacterial Canker
Causal organism: Pseudomonas syringae pv. actinidiae (PSA)
Symptoms
- Brown leaf spots with yellow halos.
- Oozing bacterial exudate from stems.
- Wilting and dieback of shoots.
- Severe infections may kill vines.
Management
- Use disease-free planting material.
- Prune infected branches during dry weather.
- Disinfect pruning tools regularly.
- Spray Copper oxychloride 3 g/L or Copper hydroxide 2 g/L after pruning.
- Avoid overhead irrigation.
2. Root Rot
Causal organisms: Phytophthora spp., Pythium spp.
Symptoms
- Yellowing leaves.
- Poor growth.
- Root decay.
- Sudden vine collapse.
Management
- Ensure proper drainage.
- Avoid waterlogging.
- Apply Trichoderma spp. around root zone.
- Drench with Metalaxyl + Mancozeb @ 2.5 g/L.
3. Botrytis Fruit Rot (Grey Mold)
Causal organism: Botrytis cinerea
Symptoms
- Soft brown fruit rot.
- Grey fuzzy fungal growth.
- Common during humid weather and storage.
Management
- Improve air circulation by pruning.
- Avoid fruit injuries.
- Spray Fenhexamid or Iprodione as recommended.
- Harvest fruits carefully and maintain cold storage.
4. Armillaria Root Rot
Causal organism: Armillaria mellea
Symptoms
- Slow decline of vines.
- White fungal growth beneath bark.
- Root decay.
- Sudden vine death.
Management
- Remove infected plants completely.
- Improve soil drainage.
- Avoid planting in previously infected fields.
- Use healthy planting material.
5. Powdery Mildew
Causal organism: Erysiphe spp.
Symptoms
- White powdery growth on leaves.
- Leaf curling.
- Reduced photosynthesis.
- Poor fruit development.
Management
- Maintain proper spacing and pruning.
- Remove infected leaves.
- Spray Wettable Sulphur @ 2 g/L or Hexaconazole 5 EC @ 1 ml/L.
Integrated Pest and Disease Management (IPDM)
Before Planting
- Select disease-free certified planting material.
- Choose well-drained soils with pH 5.5–6.5.
- Install proper drainage systems.
- Avoid sites with a history of root diseases.
Orchard Management
- Prune annually to improve light penetration and airflow.
- Remove dead, diseased, and crossing branches.
- Maintain recommended vine spacing.
- Keep orchards free of weeds and alternate host plants.
Monitoring
- Inspect vines weekly during the growing season.
- Use yellow and blue sticky traps for monitoring flying insects.
- Install pheromone traps for leaf rollers where available.
- Check the undersides of leaves for mites, scales, and mealybugs.
Biological Control
- Conserve natural enemies such as ladybird beetles, lacewings, predatory mites, and parasitic wasps.
- Apply beneficial microorganisms like Trichoderma spp. to suppress soil-borne pathogens.
Chemical Control
- Use pesticides and fungicides only when pest or disease levels exceed economic thresholds.
- Rotate products with different modes of action to delay resistance.
- Follow label directions, recommended dosages, pre-harvest intervals, and local agricultural regulations.
Conclusion
Kiwi production is highly profitable when orchards are managed proactively. Regular scouting, proper pruning, good sanitation, balanced nutrition, effective drainage, and timely interventions are the foundation of successful pest and disease management. Because bacterial canker, root rots, scale insects, leaf rollers, and spider mites can cause severe economic losses, integrating cultural, biological, and chemical measures is the most sustainable strategy for maintaining vine health, improving fruit quality, and achieving consistent, high yields.