Prevention and treatment of Leaf withering of Chinese chives

Leaf dryness often occurs in leek during the growing period, and agricultural products are often sprayed with insecticides, but the control effect is not good because the control is blind. The withered leaves of leek are caused by blight and gray mold, and some are caused by physiological diseases. Spraying insecticides is undoubtedly "the opposite way". On the other hand, the withered leaves caused by underground larvae such as onion fly and late-eye mushroom mosquito sprayed on the aboveground, and the control site was wrong. It is necessary to "prescribe the right medicine" to control the withered leaves of leek.

Withered leaves of leek

Blight withered leaves: blight is the main disease of leek in protected field. The injured part appeared watery, the leaves and mosses were dark green, while the roots and bulbs were light brown, and there was no obvious edge in the diseased part. When wet, the diseased part has white sparse mold, when dry, the diseased leaves are withered and yellow. The roots and stems of infected leeks are so soft that they can not absorb water nutrients normally, causing the aboveground parts to collapse or dry up. The occurrence of the epidemic disease is related to drainage. During prevention and control, attention should be paid to drainage and crop rotation. At the initial stage of the disease, 25% Ruidu 600 times liquid or 58% metalaxyl manganese zinc 500 times solution or 40% ethyl phosphorus aluminum 200 times solution 40kg / mu can be used once every 10 days.

Botrytis cinerea withered leaves: when the disease occurs, it first develops downward from the leaf tip. At the initial stage of the disease, there are white or light brown spots on both sides of the leaves. With the development of the disease, the disease spot expanded into fusiform or oval shape, and finally the disease spot edge piece, the disease leaf withered. When wet, a gray to gray-green and dense mildew layer occurs on the diseased leaves. In addition to drainage and dampness reduction, 50% Sukeling 1000 × 1 500 times, 20% trimethoprim 800 × 1000 times or 50% carbendazim 600 times can be sprayed twice after Chinese chive harvest and seedling height 5~8cm.

Root maggots withered leaves: root maggots are mainly onion flies and late-eye mushroom mosquitoes. Root maggots drill into the leek bulbs to eat, there are often more than a dozen or dozens of larvae, the damaged bulbs are eaten, causing decay, leaves withered and withered to death. Root drying, grass ash application or fine soil mixed with 2 kg of 5% phoxim granules per mu can be used for prevention and control. When the larvae are harmful, when it is found that the leaf tip begins to turn yellow and soften to lodge to the ground, it can be treated with 1000 times of 75% phoxim EC or 25% quinathion EC, peel off the rhizosphere topsoil, spray irrigation on the roots and cover the soil at any time. The best effect is sprayed at 9: 10 in the morning. In the adult emergence period (mid-late April, mid-June, mid-July, mid-October), spray 10% aphid lice net (also known as Chuanjing, Kangfuduo, imidacloprid, Dagongchen, etc.) 2000 × 2500 times, or 75% phoxim 1000 times or 2.5% Deltamethrin vinegar 3000 times, the spray effect is good at 9: 10 a.m. The adults of Mushroom mosquitoes like to inhabit in shade, dampness and humus. Between summer and autumn, leaf thinning ventilation can reduce the occurrence, have a tendency to light, and can be trapped and killed by frequency vibration insecticidal lamps.

The phenomena of dry tip, leaf withering and plant death of leek caused by physiological diseases are also related to soil acidification, ammonia poisoning, high temperature (more than 35 ℃) and low temperature. Calcium deficiency, boron deficiency and manganese excess can also cause leek leaf tip yellowing.