Papaya: Diseases, Symptoms and their Management

Important Topics

Papaya: Diseases, Symptoms and their Management

April 24, 2023 no responses

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1. Powdery Mildew Diseases of Papaya

Causal Organism: Fungus; Odium indicum, Odium caricae

High humidity (80-85%) and a temperature range of 24-26°C induce the development of powdery mildew in papaya.

Symptoms:

The disease appears on the foliage. Infection is first apparent on the leaves as small slightly darkened areas, which later become white powdery spots.
These spots enlarge and cover the entire leaf area.
Severely infected leaves may become chlorotic and distorted before falling.
Affected fruits are small in size and malformed.

Management:

Sulphur (30 g/10 litres of water) dusting or spraying Calixin 75 EC (5 ml/10 litres of water) at 15-day intervals aids in disease management.

2. Leaf- Blight of Papaya

Causal Organism: Fungus; Corynespora cassiicola

Symptoms:

The disease severely damages the leaves.
The disease begins with tiny, discoloured lesions that are irregularly spread over the leaves.
These spots become uneven in shape, grow in size, and change colour from brown to grey.
The specks are surrounded by a pale yellow zone.
Several lesions form and cover vast sections of the leaf, and in severe infections, the entire leaf dies.

Management:

Disease can be controlled by spraying Dithane M-45 (0.2%) starting to form the appearance of the disease symptoms.

3. Damping-Off

Causal Organism: Fungus; Rhizoctonia solani, Pythium aphanidermatum

Symptoms:

This is a disease that affects young seedlings. Lesions can be detected on the stem at or near the soil level.
The plant dies when the stem becomes wet and shrinks.

Management:

Planting should take place in well-drained soil, and the crop should not be over-irrigated.
To preserve the newly sprouting seedlings, the seeds should be treated with a fungal culture of Trichoderma viride (3-4 g/kg of seed) or Captan (3 g/kg of seed) before sowing.

4. Anthracnose Diseases of Papaya

Causal Organism: Fungus; Colletotrichum gloeosporioides

Symptoms:

The disease prominently appears on green immature fruits.
The initial symptoms are water-soaked, sunken spots on the fruit.
The centres of these spots later turn black and then pink when the fungus produces spores.

Management:

Spaying with Copper Oxychloride (3 g/litre of water) or Carbendazim (1 g/litre of water) or Thiophanate Methyl (1 g/litre of water) at 15 days interval effectively controls the disease.

5. Papaya Mosaic Virus

Causal Organism: Virus; Mosaic virus

Vector: Aphid

Symptoms:

The disease signs occur on the plants’ top young leaves.
The leaves have shrunk in size and are covered in blister-like regions of dark-green tissue that alternate with yellowish-green lamina.
The length of the leaf petiole is shortened, and the upper leaves stand upright.

Management:

The use of Carbofuran (1 kg a.i./ha) at the time of seeding, followed by 2-3 foliar sprays of Phosphamidon (0.05%) at 10-day intervals beginning 15-20 days after sowing, successfully controls the aphid population.

6. Leaf Curl Diseases of Papaya

Causal Organism: Virus; Leaf Curl Virus

Vector: White Fly (Bemisia tabaci)

Symptoms:

The disease is distinguished by severe curling, crinkling, and distortion of the leaves.
The young leaves are mostly damaged. Aside from curling, the leaves also show vein clearing and thickening.
Petioles are sometimes twisted.

Management:

Carbofuran (1 kg a.i./ha) applied to the soil at the time of sowing, followed by 4-5 foliar sprays of Dimethoate (0.05%), Metasystox (0.02%), or Nuvacron (0.05%) every 10 days, efficiently suppresses the whitefly population.

7. Papaya Ring Spot Virus

Causal Organism: Virus; Ring Spot Virus

Vector: Aphid

Symptoms:

Yellowing and vein-clearing of the young leaves are the first signs of papaya.
This is followed by prominent yellow mottling of the leaves, as well as severe blistering and leaf deformation.
The leafstalks and stem also have dark-green streaks and rings.
These are concentric rings with spots or C-shaped marks that are a darker green than the background-green fruit colouration.

Management:

Aphids can be managed by applying Carbofuran (1 kg a.i./ha) to the nursery bed at the time of seeding, followed by 2-3 foliar sprays with Phosphamidon (0.05%) every 10 days beginning 15-20 days after sowing.