Diseases of Papaya

Diseases of Papaya

Our discussion for today is all about the most common diseases of papaya. I have taken note things to remember about papaya. And here it is first the powdery mildew the infection is first apparent on the leaves as small slightly darkened areas, which later become white powdery spots and affected fruits are small in size and malformed to control this disease is as soon as the disease symptoms are observed dusting Sulphur (30 g/10 litres of water) or spraying Calixin 75 EC (5 ml/10 litres of water) at 15 days interval helps to control the disease. Then the leaf blight it causes severe damage to leaves. First appears as small, discolored lesions, which are irregularly scattered on the leaves which become irregular in shape, then increase in size, and appear brown to grey in color. To control this disease is to by spraying of Dithane M-45 (0.2%) starting from the appearance of the disease symptoms. The next disease is damping off this disease affect young seedlings and the lesions are seen on the stem at or just above soil level the stem becomes watery and shrinks, followed by death of the plant. Ways to control this disease well-drained soil should be used for planting and the crop should not be excessively irrigated. Before sowing the seeds should be treated with fungal culture of Trichoderma viride (3-4 g/kg of seed) or Captan (3 g/kg of seed) to protect the newly emerging seedlings. Next is the foot rot this is a severe disease of papaya it is characterized by the appearance of water-soaked patches on the stem near the ground level causing rotting of the tissues, which then turn dark brown or black and the fruit if formed are shriveled and malformed. Ways to control is to application of Trichoderma viride (15 g/plant) mixed in well-decomposed FYM should be applied around the root zone of the plants at the time of planting. The crop should be irrigated by adopting the ring method of irrigation so that the water does not come in direct contact with the stem. Anthracnose it appears on green immature fruits. The symptoms are in the form of brown to black depressed spots on the fruits. And the initial symptoms are water-soaked, sunken spots on the fruit. To control the affected fruits should be remove and destroyed. The fruits should be harvested as soon as they mature. 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. Fruits for exports should be subjected to hot water treatment or a fungicidal wax treatment. And the papaya mosaic this disease attacks the papaya plants of all age groups, but is most serious on young plants. Aphids are responsible for transmitting the disease. And the symptoms appear on the top young leaves of the plants the leaves are reduced in size and show blister like patches of dark-green tissue, alternating with yellowish-green lamina. Infected plants show a marked reduction in growth and the fruits are elongated and reduced in size. Ways to control good field sanitation such as removal and destruction of affected plant reduce the spread of the disease. Also, losses can be minimised controlling the population of aphid. Application of Carbofuran (1 kg a.i./ha) at the time of sowing seeds followed by 2-3 foliar sprays of Phosphamidon (0.05%) at an interval of 10 days starting from 15-20 days after sowing effectively checks the population of aphids. And the leaf curl of papaya this disease is transmitted by the vector white fly (Bemisia tabaci). And severe curling, crinkling and deformation of the leaves characterize the disease, young leaves are affected. It also exhibit vein clearing and thickening of the veins, sometimes petioles are twisted, severe cases complete defoliation of the affected plant is observed, affected plants show a stunted growth with reduce fruit yield.