Production of Pummelo, Part 3 Pest Control and Harvesting


  • Pummelo trees bear fruit 3-5 years from planting and can be harvested after 5-6 months flowering.
  • Change in color – (green to yellow with 50% color change)
  • Acid ratio is 10:1 with 9% Total Soluble Solids.
  • Oil glands in the skin becomes more prominent and shiny.
  • Juice content of 50% be weight
  • Harvest pummelo fruits either by pulling or clipping from the fruiting branches
  • The best time to harvest is around 8:00 am to 3:00 pm (with sunlight) to reduce fruit injuries on the peel of pummelo.
  • Do not harvest pummelo fruits when the rind are still wet dry it before packaging.

Post harvest Handling and Management

  • Sorting. After harvest, the fruits must be brought to a shaded area. Sort the fruits according to size, color, and rind quality. Discard fruits that are injured, bruised, and misshapen.
  • Packaging. The fruits must be placed in kaing or wooden crates lined with newspaper or other suitable materials to prevent abrasions and punctures. Size of the containers depend upon the transportation system available
  • Storing. For longer shelf life, pummelo fruits can be stored for 12-14 weeks at a temperature of 120C and 85-90% relative humidity. Under ambient conditions, the fruits have a shelf life of 5-14 days.
  • Post-harvest treatment. For longer storage life, it is recommended to dip the fruits in thiabenzadole, benomyl or 2 amino butane at the rate of 500-1000 ppm. This will sustantially prevent the spread of post-harvest diseases and reduce losses.

Pests and Diseases and their Control

Insect Pests

1. Rind borer (Prays endolemma)

Plant Part Damage: Newly opened flowers and young fruits.
Control Measures: Apply pre and post bloom sprays with the use of either Cymbush, Gusathion, Decis at recommended dosage; Collect and burn or bury infested fruits.

2. Scale Insects

a. Snow scale ((Pinnaspis sp)

Plant Part damage: Trunks and twigs
Control Measures: Apply Dimethoate and oil-based materials

b. Black scale (Saissetia kemisphaerica)

Plant Part Damage: Trunks, twigs, and leaves
Control Measures: Spray malathion and recommended dosage.

3. Mites

Plant Parts Damage: Leaves and fruits
Control Measures: Spray Dicarzol, Kelthane, Malathion, Dimethoate

Bacterial and Fungal Disease

1. Citrus canker (Xanthomonas citri)

Symptoms: Lesion on both sides of the leaf and fruit ridges on the fruit
Transmission: Contaminated budwood, man, animals, tools, and wind
Management:: Burn severely infected trees or eradication; Spray any copper-based fungicide

2. Foot Rot (Phytophtora sp) Gummosis

Symptoms: Sap oozing from small cracks on the bark; lesions spread around the trunk

Management:: Use resistant rootstock; avoid deep planting; water management; aeration around the crown; surgical treatment; treat with copper-based fungicide

3. Pink Disease (Corticium salmonicolor)

Symptoms: White fan-shaped coating of mycelia growth becomes pink; Bark is destroyed, girdled and die

Management: Remove affected barks of trunks and prune diseased parts; disinfect by spraying copper fungicide or lime sulfur mixture

4. Fruit Rot (Diplodia natalens)

Management: Burn rotten fruits to prevent spread of the spores

5. Scab (Sphaceloma faucetti)

Symptoms: Disease starts as small, pale orange, circular spots on young fruits. As disease advances and fruits start to mature, several lesions coalesce and form irregularly shaped spots.
Management: Spray copper fungicides at the time when new flushes of growth appear or at time of blooming when two-thirds of petals have fallen. Successive sprays may follow two weeks thereafter up to the time when fruits are half matured.

Virus and Virus-like Diseases

1. Greening/Leafing mottling

  • Causal Organism: Fastidious bacteria
  • Carrier: Diaphorina citri (Jumping plant lice)
  • Integrated Disease Management:
  • Eradicate infected plants
  • Use disease-free planting materials
  • Shoot tip grafting
  • Health indexing and spraying of insecticides (Dimethoate) on citrus trees at shooting stage
  • Biological control of psyllid vector (Octoparasites)

2. Triztesa (Virus)

Symptoms: Stem pitting
Most varieties of citrus are affected by stem pitting disease which develop large number of pits on trunks and stems

  • Carrier: Brown citrus aphids (Toxoptera citricidus)
  • Black citrus aphids (Toxoptera aurantii)
  • Melon aphid (Aphis gossipii)
  • Integrated Disease Management:
  • Use of resistant rootstocks
  • Mother trees where scions are obtained should be periodically examined and indexed

3. Exocortis (viroid)

  • Symptoms: Yellow stem blotches and dark splits; die-back; stunting; reduced yield
  • Carrier: Infected budwood, nursery tools
  • Integrated Disease management:
  • Selection and indexing test of non-infected budwood
  • Use of healthy budwood
  • Use shoot tip grafting to eliminate the pathogen
  • Disinfect tools used for budding and pruning with household chlorox.

4. Xyloporosis (viroid like)

  • Symptoms: Mild wood pitting to advance bark scaling; wood disorganization and impregnation of affected tissues with gums
  • Carrier: Infected budwood, nursery tools, and contaminated equipments
  • Integrated Disease management:
  • Selection and indexing test of non-infected budwood
  • Use of healthy budwood
  • Disinfect tools used for budding and pruning with household chlorox.

5. Psorosis (complex of viruses)

  • Symptoms: Chlorotic blotching in young and mature leaves; bark scaling of branches and trunks
  • Carrier: Infected budwood
  • Integrated Disease management:
  • Use of indexed budwood and seeds free of psorosis
  • Scions should be cut only from indexed trees known to be free from Taller leaf virus

6. Tatter leaf virus

  • Symptoms: Stunted growth
  • Carrier: Infected budwood and sap transmissible
  • Integrated Disease Management: Infected materials can be made virus-free by combination of heat treatment and shoot tip grafting (STG)

For more info, contact:

Dept.of Agriculture
D.A. Compound, Elliptical Rd., Diliman,Quezon City
Tel. Nos. (632) 929-6065 to 67 / 920-3991 / 928-1134


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