Ppt on Major Diseases Of Mango: Symptoms Pathogens And Management

Mango, a major tropical fruit crop, is susceptible to a range of fungal, bacterial, and algal diseases that can significantly impact yield and fruit quality. Understanding the symptoms, causal organisms, and management strategies for these diseases is essential for sustainable mango production. This presentation provides an overview of the most important mango diseases, their identification, and integrated management approaches.

Major Diseases of Mango

  • Anthracnose (Colletotrichum gloeosporioides)
  • Powdery mildew (Oidium mangiferae)
  • Mango malformation (Fusarium moniliforme var. subglutinans)
  • Stem end rot (Botryodiplodia theobromae)
  • Red rust (Cephaleuros virescens)
  • Grey blight (Pestalotia mangiferae)
  • Sooty mould (Capnodium mangiferae)

Anthracnose: Symptoms and Causal Organism

  • Caused by Colletotrichum gloeosporioides, a widespread fungal pathogen.
  • Symptoms include leaf spots, blossom blight, wither tip, twig blight, and fruit rot.
  • Small, blister-like spots develop on leaves and twigs; young leaves wither and dry.
  • Fruits show black spots; pulp hardens, cracks, and decays at ripening, leading to fruit drop.
  • Severe infections cause dieback of branches and significant yield loss.

Anthracnose: Management

  • Spray Pseudomonas fluorescens (FP 7) at 3-week intervals from October at 5 g/liter on flower branches.
  • Apply 5–7 sprays, including applications on flowers and fruit bunches.
  • Pre-storage treatment: hot water (50–55°C) for 15 minutes or dip in Benomyl (500 ppm) or Thiobendazole (1000 ppm) for 5 minutes.
  • Practice field sanitation and remove infected plant debris to reduce inoculum.

Powdery Mildew: Symptoms and Causal Organism

  • Caused by Oidium mangiferae (syn. Acrosporium mangiferae).
  • Affects leaves, flowers, panicle stalks, and young fruits.
  • White powdery growth appears on affected parts; severe infection leads to leaf shedding.
  • Infected fruits fail to develop and may drop at pea size.
  • Pathogen survives as dormant mycelium in leaves; spreads by airborne conidia.

Powdery Mildew: Management

  • Dust plants with fine sulphur (250–300 mesh) at 0.5 kg/tree.
  • First application after flowering, second after 15 days.
  • Alternatively, spray wettable sulphur (0.2%), Carbendazim (0.1%), Tridemorph (0.1%), or Karathane (0.1%).
  • Ensure good air circulation and avoid excessive irrigation to reduce humidity.

Mango Malformation: Symptoms and Causal Organism

  • Caused by Fusarium moniliforme var. subglutinans.
  • Three symptom types: bunchy top phase, floral malformation, and vegetative malformation.
  • Bunchy top: thickened, stunted shoots with rudimentary leaves in nursery plants.
  • Vegetative malformation: excessive, swollen branches with short internodes, forming bunches.
  • Floral malformation: abnormal panicles, dried malformed heads persisting on trees; witches' broom appearance.

Mango Malformation: Management

  • Destroy diseased plants and use disease-free planting material.
  • Spray 100–200 ppm NAA (naphthalene acetic acid) during October to reduce incidence.
  • Prune diseased parts along with 15–20 cm of healthy tissue.
  • Follow up with Carbendazim (0.1%) or Captafol (0.2%) sprays.

Stem End Rot: Symptoms and Causal Organism

  • Primarily caused by Botryodiplodia theobromae (syn. Diplodia natalensis).
  • Initial symptom: darkening of epicarp around fruit pedicel, forming a circular black patch.
  • Under humid conditions, infection spreads rapidly, turning the whole fruit black within days.
  • Pulp becomes brown and soft; disease often spreads from dead twigs and bark, especially during rains.

Stem End Rot: Management

  • Prune and destroy infected twigs to reduce inoculum.
  • Spray Carbendazim or Thiophanate-methyl (0.1%) or Chlorothalonil (0.2%) at fortnightly intervals during rainy season.
  • Maintain orchard hygiene and avoid injuries to fruits during harvest.

Red Rust: Symptoms and Causal Organism

  • Caused by the algal pathogen Cephaleuros virescens.
  • Rusty, circular, slightly elevated spots appear on leaves and young twigs.
  • Spots may coalesce to form irregular lesions; mature spores fall off, leaving a cream to white velvety texture.
  • Reduces photosynthetic area and weakens affected branches.

Red Rust: Management

  • Spray Bordeaux mixture (0.6%) or copper oxychloride (0.25%) on affected trees.
  • Remove and destroy heavily infected plant parts to limit spread.

Grey Blight: Symptoms and Causal Organism

  • Caused by Pestalotia mangiferae.
  • Brown spots develop on leaf margins and tips, enlarging and turning dark brown.
  • Black acervuli (fruiting bodies) appear on spots; fungus survives on leaves for over a year.
  • Spread by wind-borne conidia; severe during monsoon with 20–25°C temperature and high humidity.

Grey Blight: Management

  • Remove and destroy infected plant parts to reduce inoculum.
  • Spray copper oxychloride (0.25%), Mancozeb (0.25%), or Bordeaux mixture (1.0%).

Sooty Mould: Symptoms and Causal Organism

  • Caused by Capnodium mangiferae, a saprophytic fungus.
  • Superficial black mycelial growth develops on leaves, stems, and fruits.
  • Fungus grows on honeydew secreted by sap-sucking insects (jassids, aphids, scale insects).
  • Black encrustation reduces photosynthetic activity and fruit quality.

Sooty Mould: Management

  • Simultaneously manage sap-sucking insects and sooty mould.
  • Spray systemic insecticides such as Monocrotophos or methyl demeton to control insect vectors.
  • Apply starch solution (1 kg starch/maida in 5 liters water, boiled and diluted to 20 liters) to affected parts; dried starch flakes remove fungus.

Objective Questions

Q1. Which pathogen is responsible for causing anthracnose in mango?
A. Colletotrichum gloeosporioides
B. Oidium mangiferae
C. Fusarium moniliforme var. subglutinans
D. Botrydiplodia theobromae
Answer: A

Q2. Which of the following is NOT a symptom of mango malformation caused by Fusarium moniliforme var. subglutinans?
A. Bunchy top phase in nursery
B. Black encrustation on leaves
C. Floral malformation
D. Vegetative malformation
Answer: B

Q3. Which management practice is recommended for controlling powdery mildew in mango?
A. Dusting fine sulphur at 0.5 kg/tree
B. Spraying Bordeaux mixture 1.0%
C. Treating fruits with hot water at 50-55°C
D. Spraying Monocrotophos
Answer: A

Q4. Which disease of mango is characterized by the formation of black encrustation on leaves due to fungal growth on sugary secretions?
A. Sooty mould
B. Grey blight
C. Red rust
D. Anthracnose
Answer: A

Q5. Which chemical is NOT recommended for the management of mango anthracnose before storage?
A. Benomyl (500 ppm)
B. Thiobendazole (1000 ppm)
C. Wettable sulphur (0.2%)
D. Hot water treatment at 50-55°C
Answer: C

Q6. The causal organism of stem end rot in mango is:
A. Diplodia natalensis
B. Cephaleuros mycoides
C. Pestalotia mangiferae
D. Capnodium mangiferae
Answer: A

Q7. Which symptom is specifically associated with red rust of mango?
A. Rusty, circular, slightly elevated spots on leaves
B. Brown spots with black acervuli on leaf margins
C. Black spots on fruit with hardening of pulp
D. Black encrustation affecting photosynthesis
Answer: A

Q8. Which of the following is a recommended management strategy for grey blight in mango?
A. Spraying copper oxychloride 0.25%
B. Dusting with fine sulphur
C. Spraying systemic insecticides
D. Dipping fruits in Benomyl solution
Answer: A

Q9. What is the primary mode of secondary spread for powdery mildew in mango?
A. Air borne conidia
B. Rain splash
C. Insect vectors
D. Soil-borne sclerotia
Answer: A

Q10. Which of the following is NOT a recommended management practice for sooty mould in mango?
A. Spraying systemic insecticides for insect control
B. Spraying starch solution to remove fungus
C. Spraying Bordeaux mixture 1.0%
D. Removing flakes formed by dried starch
Answer: C