Disease caused by dead leaves
The disease is the main disease of the leeks in the protected areas. The affected areas were water-stained. The diseased parts of leaves and floral moss were dark green, but the roots and bulbs were light brown. The diseased parts had no obvious edges. The diseased part produces white sparse mildew when it is wet, and the diseased leaves become dry yellow when dry. The soft rot of the infected plant's roots and stems cannot normally absorb water and nutrients, resulting in the overlying or dry parts of the ground. The occurrence of the disease is related to drainage. During the prevention and treatment, attention should be paid to drainage, dehumidification, and rotation. In the early stage of disease, 25% of thioredox may be used 600 times, or 58% of metalaxyl MnZn may be 500 times or 40% of EDP 200-300. Doubling liquid 40 ~ 50 kg per mu, 7 to 10 days once.
Dead leaves caused by gray mold
At the time of onset, the tip of the blade first developed downwards, and white or light brown spots appeared on the front and back of the blade at the onset of the disease. As the disease progresses, the lesion expands into a fusiform or elliptical shape, and finally the lesions are flaky and the diseased leaves are dry. When wet, the diseased leaves produce a layer of gray to gray-green and dense mold. In addition to control and drainage in addition to wet down, available 50% speed Keling 1000 ~ 1500 times liquid, spray once in 20 days, 20% Triadimefon 800 ~ 1000 times liquid or 50% carbendazim 600 times liquid, after the leek harvest and seedling height Spray 2 times when 5-8 cm.
Dead leaves caused by dead leaves
Root lice are the most recent pests, mainly onion fly and late-wing gnat mosquitoes. As the roots penetrate into the bulbs, they often have more than a dozen or dozens of larvae. The victim's bulbs are eaten into empty holes, causing the decayed leaves to turn brown and fade to death. Control can be used on the sun root, apply grass ash or 5% phoxim granules per acre 2 kg mixed with fine soil sprinkled near the leeks and then covered with soil. During the period of larvae damage, it was found that the tip of the leaf began to yellow and become soft and lodging on the ground. It can be controlled by irrigating, and 75% phoxim EC can be used 500 times or 25% quizopriosin EC 1000 times to break open the topsoil of the rhizosphere. Sprinkler irrigation, covering the soil at any time, spraying at 9 to 10 am is best. In the adult emergence period (in late April, mid June, late July, mid 10 October), spray 10% osmium (also known as once-in-a-time, Kangfu-do, imidacloprid, Dagong et al) from 2000 to 2500 times , Or 75% of phoxim 1000 times or 2.5% of cyanuric chloride vinegar 3000 times, 9 to 10 am spray effect. Late-infested adult mosquitoes live in multiple shades, damp, and humus habitats. During the summer and autumn, the ventilation of the leaves can be reduced. The light tends to be polarized and can also be trapped and killed by frequency-vibration insecticidal lamps.
Dead leaves caused by physiological diseases
The phenomenon of dry tip, leaf dry, and dead plant occurs in leek, and sometimes it is related to soil acidification, ammonia poisoning, high temperature (above 35°C) and low temperature causing white tip and rotten leaves. The lack of calcium, lack of boron, and excessive manganese may also cause tip yellow. Can take targeted preventive measures.
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