Major Papaya diseases are given below:-
1.Papaya Stem rot / Foot rot: Pythium aphanidermatum
- Water soaked spot in the stem at the ground level which enlarges and griddle the stem.
- The diseased area turns brown or black and rot.
- Terminal leaves turn yellow drop off.
- The entire plant topples over and dies.
- Forward by rain. R. solaniis favoured by dry and hot weather.Common in 2-3-year-old trees.
- Seed treatment with Thiram or Captan 4 g/kg or Chlorothalonil.
- Drenching with Copper oxychloride 0.25 % or Bordeaux mixture 1% or Metalaxyl 0.1%.
2.Papaya Powdery mildew: Oidium caricae
- While mycelia growth appears on the upper surface of the leaf, flower stalks and fruit.Seven attack causes yellowing and defoliation of leaves.
- Spray Wettable Sulphur 0.25% or Dinocap 0.05% or Chinomethionate 0.1%or Tridemorph 0.1%.
3.Papaya ring spot: Papaya ring spot virus
- Vein clearing, puckering and chlorophyll leaf tissues lobbying in.
- Margin and distal parts of leaves roll downward and inwards, mosaic mottling, dark green blisters, leaf distortion which results in shoe string system and stunting of plants.
- On fruits, circular concentric rings are produced.If affected earlier no fruit formation.
- Vectored by aphids Aphis gossypii, A. craccivora and also spreads to cucurbits, not through seeds.
- Raise papaya seedlings under insect-proof conditions.
- Plant disease free seedlings.
- Raise sorghum/maize as barrier crop before planting papaya.
- Rogue out affected plants immediately on noticing symptoms.
- Do not raise cucurbits around the field.
4.Papaya Leaf curl: Papaya leaf curl virus
- Curling, crinkling and distortion of leaves, reduction of leaf lamina, rolling of leaf margins inward and downward, thickening of veins.
- Leaves become leathery, brittle and distorted.Plants stunted.Affected plants does not produce flowers and fruits.
- Spread by whitefly Bemisia tabaci.
- Uproot affected plants.
- Avoid growing tomato, tobacco near papaya.
- Spraying with systemic insecticides to control the vector.
5.Papaya Anthracnose: Colletotrichum gloeosporioides
- If affect leaf and stem on erotic spots are produced.On fruit initially, brown superficial discoloration of the skin develops which is circular and slightly sunken.
- Then they coalesce in which sparse mycelial growth appear on the margins of a spot.
- Under the humid condition, salmon pink spores are released.Fruits mummified and deformed.
- Infection is caused by fruit from the field. Secondary spread by conidia by rain splashes.
- TamilNadu Agritech Portal