In the growing season of leeks, leaf dryness often occurs. Farmers often spray insecticides on the shoots of plants. Because the objects are blind, the general control effect is not good. Because the leek leaves are caused by the disease, gray mold, and some are caused by physiological diseases, spraying insecticide is undoubtedly the "north of the north." On the other hand, dry leaves caused by underground larvae such as the onion fly and the late-to-earth gnat-spotted mosquitoes are sprayed with medicaments on the ground, and there are also problems in the prevention and control. The prevention and treatment of leeks and leaves is still a good choice for the right medicine.
I. 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 excess manganese also cause tip yellow. Can take targeted preventive measures.
Second, the disease caused by dead leaves
The disease is the main disease of leeks. 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 EB 200-300. Doubling fluid per acre 40 to 50 kg, 7 to 10 days once.
Third, the root cause of the 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 sucked 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, and can be controlled by irrigating. It can be used 75% phoxim EC 500 times solution or 25% quizal EC 1000 times solution, breaking the rhizosphere top soil, to the root Sprinkler irrigation, covering the soil at any time, spraying the best results from 9 to 10 am In the adult emergence period (in late-April, mid-June, late July and mid-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. Between summer and autumn, the ventilation of the leaves can be reduced, and the light tends to be polarized. They can also be trapped with frequency-vibration insecticidal lamps.
IV. Dry 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.
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