RUBBER NEWS

Plant Protection and Major Leaf Diseases in Vietnam’s Rubber Plantations

Posted on by content02.vinahugo
13
Oct

Plant protection plays a vital role in ensuring sustainable latex yield and long-term productivity in Vietnam’s rubber plantations. The following guidelines summarize the key plant protection regulations and common leaf diseases affecting rubber trees, along with proper management methods.

1. General Regulations on Plant Protection

  • When disease symptoms appear, immediate treatment must be applied according to the official Plant Protection Procedures.

  • If new or unknown pests or diseases are detected, report immediately to the Vietnam Rubber Group (VRG) and send samples to the Rubber Research Institute of Vietnam (RRIV) for analysis (sampling instructions in Appendix XII).

  • Regularly access the official platform:
     “Rubber Tree Disease Diagnosis”
    to stay updated on pest alerts and VRG directives.

  • Do not use pesticides whose active ingredients have not been tested for efficacy.

  • Use only recommended concentrations, expressed in percentage (%) or parts per million (ppm).

  • Avoid heavy-metal-based pesticides (copper, lead, etc.).

  • Always mix chemicals with clean, neutral pH water.

  • Follow safety guidelines during pesticide handling and application.

  • Disease severity assessment and mixing methods are detailed in Appendices XII & XIII.

2. Major Pests and Diseases on Rubber Trees

Rubber trees are attacked by various fungi, insects, and environmental stresses at different growth stages.

Tree Part Major Diseases & Pests Typical Damage
Leaves Powdery mildew, Anthracnose, Rainy-season leaf fall, Corynespora, Bird’s-eye spot, Pestalotiopsis Leaf fall, reduced photosynthesis, yield loss
Branches Pink disease, Dieback, Lightning injury Branch drying, canopy loss
Trunk Bark stripe canker, Fusarium rot, Dry tapping panels Bark lesions, reduced latex flow
Roots Brown root disease, Collar rot Root decay, tree death
Insects Weevils, red mites, mealybugs, scales, termites Sap sucking, root damage, defoliation

Section I – Major Leaf Diseases

Powdery Mildew (Oidium heveae Steinm.)

  • Distribution: Nationwide, severe during annual leaf-flushing periods.

  • Damage: Causes defoliation of young leaves and flowers.

  • Symptoms: White fungal growth on both leaf surfaces.

  • Control:

    • Tebuconazole 0.0125 % (125 ppm) or Hexaconazole 0.01 % (100 ppm) + adhesive 0.2 %.

    • Spray evenly when 15 % of trees show leaf buds (“bird-foot” stage); stop when 80 % have stable foliage.

    • 8–10 day interval; 400–700 L/ha; spray only in cool hours (morning or late afternoon).

Anthracnose (Colletotrichum gloeosporioides)

  • Occurrence: During rainy season; attacks shoots and young leaves.

  • Symptoms: Leaf tips turn black and curl; severe cases cause shoot dieback.

  • Control:

    • Use Hexaconazole, Tebuconazole, Propiconazole, or Pyraclostrobin (50–125 ppm) + adhesive 0.2 %.

    • Apply every 7–10 days in cool weather until 80 % of trees have mature leaves.

Rainy-Season Leaf Fall (Phytophthora botryosa & P. palmivora)

  • Occurrence: Prolonged wet seasons.

  • Symptoms: White latex nodules on fallen petioles.

  • Control:

    • Nursery/immature trees: Spray Metalaxyl 0.07 % (700 ppm); apply 0.35 % (3500 ppm) paste on infected shoots.

    • Mature trees: Apply Metalaxyl 0.35 % on tapping panels to prevent bark canker; fertilize 50 kg urea/ha after defoliation.

Corynespora Leaf Fall (Corynespora cassiicola)

  • Occurrence: Year-round; peaks in May–June and August–September.

  • Damage: Severe on clones RRIV 3 & RRIV 4; causes mass defoliation and reduced yield.

  • Control:

    • Use Tebuconazole 0.0125–0.015 %, Hexaconazole 0.01 %, or Pyraclostrobin 0.005 % + adhesive 0.2 %.

    • Spray every 7–10 days; 600–700 L/ha; treat neighboring plots with same clone.

    • Stop tapping if infection is severe; increase potassium fertilizer by 25 %.

    • Destroy fallen infected leaves annually.

Bird’s-Eye Spot (Drechslera heveae)

  • Occurrence: Common in nurseries on poor or water-logged soils.

  • Symptoms: Round, white-centered lesions with dark brown borders (“bird-eye” appearance).

  • Control:

    • Keep plots clean and well-ventilated; apply balanced fertilizers.

    • Spray Hexaconazole 0.01 %, Propiconazole 0.0125 %, or Pyraclostrobin 0.005 % + adhesive 0.2 % at 7–10 day intervals in cool hours.

Pestalotiopsis Leaf Fall

  • Pathogen: Pestalotiopsis sp. – newly reported in Indonesia, Thailand, Malaysia, and Sri Lanka (not yet found in Vietnam).

  • Damage: Affects mature leaves, causing defoliation and latex loss.

  • Symptoms: Rust-colored or brown fish-scale-like lesions that merge into large patches.

  • Control:

    • Prevent introduction into Vietnam.

    • Strengthen general plant health and monitor regularly.

    • If detected, immediately report to VRG Technical Department or RRIV Plant Protection Division.

    • Effective fungicides: Hexaconazole, Propiconazole, Chlorothalonil.

Conclusion

Effective plant protection is crucial to maintaining Vietnam’s position as one of the world’s top rubber producers.
Applying proper fungicide protocols, field monitoring, and integrated pest management ensures sustainable latex yields and healthier plantations.