TNAU Agritech Portal
  Home | About Us | Success Stories | Farmers Association | Farmers' Innovation | Publications | Contact
Post Harvest Diseases :: Citrus
  1. Anthracnose: Colletotrichium gloeosporioides
  2. Septoria spot: Septoria depressa
  3. Blue & Green Mould: Penicillium digitatum (green mould) and P. italicum (blue mould)
  4. Sour Rot: Galactomyctes citri-aurantii (formally, Geotrichum candidum)

1. Anthracnose: Colletotrichium gloeosporioides.

Symptoms

  • Superficial leathery appearance
  • Silver/grey to dark lesions.
  • Tear-staining pattern common.
  • Pink tinge (spores) under humid conditions.

Occurrence

  • Infection occurs by rain-splash during autumn.
  • Ethylene degreening increases sensitivity to anthracnose.

Management

  • Dead wood should be pruned as the fungus harbours in dead branches.
  • Field sprays of copper-based fungicides should be applied prior to autumn rains.
  • Postharvest treatment with Benzimidazole fungicides may reduce fruit losses.

2. Septoria spot: Septoria depressa.

Symptoms

  • Dark brown collapsed lesions, with a purple tinge.
  • Black specks develop in decayed area.

Occurrence

  • Mainly inland citrus regions.
  • Infection occurs in autumn but remains dormant until cool conditions.
  • Fruit more susceptible after frosts.

Management

  • Field application of copper-based fungicides.

3. Blue & Green Mould: Penicillium digitatum (green mould) and P. italicum (blue mould).

Symptoms

  • Softening of damaged tissue.
  • White fungal growth, which progressively turns blue or green as spores develop.
  • Postharvest fungicides (Imazalil) can arrest spore development resulting in white only fungal growth.
     

Occurrence

  • Infections develop from damaged areas.
  • The growth of mould increases with storage temperatures (up to an optimum of 27 oC).
  • Late season fruit more susceptible.
  • Damaged rind is more susceptible.

Management

  • Careful handling reduces damage to rind.
  • Good hygiene and sorting reduces spore load and infection rates.
  • Sanitation destroys spores in recirculating water and packingline equipment.
  • Postharvest fungicides should be applied within 24h of harvest.
  • Lower storage temperatures slow down fungal development.

4. Sour Rot: Galactomyctes citri-aurantii (formally, Geotrichum candidum).

Symptoms

  • Very soft, watery decay.
  • Distinct margin between decayed and healthy tissue.
  • Sour odour detectable.

Occurrence

  • Infection occurs in damaged fruit.
  • Fungicide used to control blue & green moulds may not control Sour rot. (eg., USA accepted
  • fungicides).
  • Sour rot spores in soil can accumulate in recirculating water in dips and drenches.
  • Spreads by contact after packing creating nests of infected fruit in boxes.

Management

  • Careful handling reduces rind damage.
  • Apply Guazatine fungicide within 24hrs of harvest.
  • Strong emphasis of sanitisers when Guazatine fungicide not approved for use.


Home | About Us | Success Stories | Farmers Association | Publications | Site Map | Disclaimer | Contact Us

© 2014 TNAU. All Rights Reserved.