What are the latest control methods for papaya mosaic virus disease?
The whole papaya plant is a treasure, with high nutritional value, but when growing papaya, special attention must be paid to the harm of pests and diseases, especially the harm of papaya mosaic virus disease, which has a huge impact on yield and quality. Below, the editor will introduce the control methods for mosaic virus disease, hoping to help everyone.
1. Disease symptoms
Mosaic virus disease generally appears after papaya has been grown for 2-3 years. The disease is transmitted by aphids, and the incubation period can last as long as half a month. Disease symptoms appear on all parts of the papaya plant. When leaves are affected, the veins of young leaves become wrinkled, the leaf margins and tips curl downward, and the base of the petiole develops dot-like or streak-like water-soaked lesions. In the middle stage of the disease, yellow spots appear at the top, and the veins lose their green color and appear as transparent dots. In the late stage of the disease, the upper young leaves become transparent, the middle leaves show mottling, the veins have water-soaked net-like patterns, and the entire leaf becomes uneven and bumpy, with the growth of the terminal leaves inhibited. When the stem is affected, the young stem at the top shows streak-like or block-like water-soaked areas; after flowers and fruits are infected, the petals develop water-soaked lesions, and in severe cases the normal petals become deformed. Lesions on the fruit are gradually seen only after the fruit expands, appearing as round or oval concentric rings, and in severe cases irregular tumor-like growths appear on the fruit surface.
2. Control methods
1. Shorten the growing period
Papaya is a perennial fruit tree, and mosaic virus disease generally appears only after 2-3 years of planting. If annual cultivation is practiced, the occurrence of this disease can be avoided.
2. Strengthen orchard management
It is best to practice crop rotation in papaya plantations, open up new orchards as much as possible, strengthen fertilizer and water management in the orchard, drain standing water promptly in summer, and provide appropriate drought resistance during dry periods. At the same time, appropriately increase the application of phosphorus and potassium fertilizers and farmyard manure to improve the disease resistance of the plants, encourage early flowering and fruiting, and early harvest, so as to achieve harvest in the same year as planting and reduce the harm of mosaic virus disease.
3. Clean the orchard
Plant in spring and harvest in autumn. After harvest, cut down the plants immediately. When cleaning the orchard in winter, spread a layer of lime powder over the whole orchard or spray once with lime sulfur mixture, which can prevent the reproduction of pathogens.
4. Control
Controlling aphids in a timely manner can reduce the spread of this disease. When aphids are found, they can be killed by spraying dimethoate emulsifiable concentrate. In the early stage of the disease, promptly prune off diseased leaves and diseased fruits to reduce the spread of the disease. Apply pesticides promptly in the early stage of the disease, generally spraying once every 5-7 days for 3-4 consecutive applications. Commonly used agents include ningnanmycin aqueous solution, mixed fatty acid aqueous emulsion, and moroxydine hydrochloride · copper acetate.
The above is an introduction to the control methods for papaya mosaic virus disease. We hope it can help you. If you want to learn more related knowledge, please follow us.