Papaya plants are bearing fruits, but after four or five fruits, the leaves turn pale and shrink as they go up. Does your plant have the same problem? Why is this happening?
Just like us human beings, papayas are also being susceptible to diseases caused by viruses and the COVID-19 among them is ringspot virus.
What is this Ringspot Virus?
Papaya ringspot virus (PRSV) is a pathogenic plant virus which primarily infects the papaya tree. It was first detected in 1937 and commercial papaya production got twice attacked by PRSV in Hawaii.
How does this spread?
Planting of diseased seedlings or sucking pests can spread this disease. The disease is said to be transmitted from plant to plant by aphids. White flies are also carriers of the virus. Watermelon, Musk melon, Ridge gourd, Bottle gourd, snake gourd can act as the collateral hosts for the virus if grown closer to papaya trees.
What are the symptoms?
- Top leaves begin to have yellow mosaic in the leaf blade.
- Green oily streaks appear on the stem and petiole of younger leaves.
- These ring spots appear on flowers and fruits.
- Can cause production loss between 5-100% depending on the age in which the plant is affected.
How to manage the spread of PRSV?
- Thoroughly screen the nursery bed for the infected seedlings and remove them carefully.
- Transplant only healthy seedlings and remove the diseased plants in the main field.
- Weeds should be removed which may act as an additional hosts for the virus.
- Spray neem oil-soap mixture (5 ml neem oil, one liter of water, 10 g of soap) mixed with Pseudomonas solution (20 g of Pseudomonas in one liter of water).
- Or spray 2 ml of Nimbicidin mixed with one liter of water followed by the spraying of 20 g of Verticillium mixed in one liter of water.
- If the infection is severe, spray 5 g of Thiomethoxam diluted in 20 liters of water.
- In addition to this, 10 g of magnesium sulphate solution can be sprayed on the fruit bearing trees to maintain the health of the leaves.