Leek grub: mainly larvae in the ground hazards, grubs eat germinated seeds underground, bite off the rhizome of seedlings, resulting in the death of the whole plant, serious caused by lack of seedlings and ridges.
Control measures: In the plot where grubs occur heavily, irrigate the roots with 80% dimethoate soluble powder and 25% cilvine wettable powder 800 times each, and irrigate 150 to 250 grams per plant, which can kill the larvae near the rhizosphere.
Control of leek maggot larvae: 50% octyl thiophos emulsion 1000 times liquid, 48% Lesben emulsion 500 times liquid, 1.1% matrine powder 500 times liquid root irrigation, once a month. When larval infestation occurs in the field, combined with watering, 15 to 20 kg of ammonium bicarbonate are applied with water per acre of land, which is said to kill the larvae.
Leek leek maggots: the bulbs and tender stems where larvae gather in the underground leek. It usually occurs in four generations a year, in early May, mid-June, early August, and late September. Adults lay eggs in the soil cracks or soil blocks around the leek plant, and after the larvae hatch, the bulbs and tender stems gathered in the underground part of the leek are harmed, causing the young stems to rot, making the leek leaves wither and yellow, until they rot and die, and in severe cases, the whole leek plant dies.
Leek jumping blind bug: Adult and nymphs suck leeks, producing white to light brown spots, and severe insects per square meter nearly a thousand. Causes the leaves of the whole plant to turn yellow and wilt. Control methods: spray 2.5% cypermethrin emulsion or 20% cypermethrin emulsion 2000 times liquid, 10% imidacloprid wettable powder 2000 times liquid, 50% octathion emulsion 1500 times liquid, etc. Spray once every 6 to 8 days, 2-3 times.
Yellow leaf disease of leeks: at the beginning of the disease, from the leaf tip and leaf margin to the middle vein, half of the leaf (longitudinal) turns yellow or the whole leaf turns yellow, and the later lesion becomes a dark yellow water stain, gradually necrotic, resulting in the death of the whole leaf.
Leek blight: Dark green water-stained spots with inconspicuous edges appear in the leaf lesions, which can reach more than half (lateral) after enlargement. After the loss of water, the diseased tissue shrinks and is bee-waist-shaped, and the leaves are yellowed and wilted. The leaf sheath is damaged by brown water-soaked spots, soft rot, and leaf peeling. The flower stems are damaged and produce brown spots, which wither and droop in the later stages.