First, yellow leaf disease Symptoms: Cabbage, yellow bud and other Chinese cabbage, Chinese cabbage yellow leaf disease occur from north to south. See the onset of disease at the seedling stage. After planting or planting, the growth is slow, and the leaves are chlorotic, causing half or whole leaves to wilting, which seems to be lack of water. The diseased plant is pulled up, the roots are small, the main root is cut, the vascular bundle is browned, and the leaves are replaced by the leaves after the rosette. Beginning of yellowing, entering the middle of the core, the leaves of the old leaves fade and turn yellow, the leaves around the veins remain dark green, the back leaf leaves shrink and shrink inward, causing the plants to shrink or die. Control method: It can be mixed with 800 times of mycobacteria and 600 times of mixed solution, and then sprayed with 450 times of cupidin. Second, downy mildew Symptoms: It can occur from the seedling stage to the mature stage and even the seed collection. Most of the leaves begin to develop from the lower leaves, and the chlorotic spots of the shape begin to appear in the front of the leaves, gradually expanding, and the polygons are polygonal due to the limitation of the veins. When wet, the surface of the lesion will grow loose and white mold layer on both sides. When many lesions are connected, the leaves will fall off early. This develops from the lower leaves to the middle and upper leaves. Irregular black-brown spots appear on the stems, and white mold layers are also present. The pedicels and seed pods of the seedlings also produce dark brown spots like stems, which can cause swelling and distortion of the diseased parts, and the petals turn green. The seed pods are thin and thin, and the diseased part also grows white mildew. Prevention: 1. Seeds or disease-free seedlings are selected from disease-free or disease-free plants; 2. Rotating with non-cruciferous vegetables for more than 2 years; 3, remove the diseased plant residues, centralized treatment; timely topdressing, watering, to enhance resistance; 4, the initial stage of the disease with 72.2% Plex water 600 ~ 800 times solution, or 75% chlorothalonil WP 500 times solution, or 64% anti-virus 矾 500 times liquid spray control, spray every 7 to 10 days , even spray 2 to 3 times. Third, black rot Symptoms: Black rot is mainly cruciferous vegetables such as cabbage, cabbage, broccoli and radish. Typical symptoms are caused by vascular bundle necrosis and blackening, but the diseased part does not soften, does not emit malodor, and is different from soft rot. Seedlings and adult plants can be affected, and the radish seedlings can occur at the seedling stage, showing cotyledons, and the heart leaves withered and dried. When the adult plants are affected, the lesions form V-shaped or irregular yellow-brown lesions from the leaf margins, and then the bacteria spread along the petiole to the roots and roots, so that the vascular bundles of the rhizomes become black and the leaves die. The external symptoms of the fleshy roots are not obvious, and the internal vascular bundles turn black. In severe cases, the meat is dry and rot, forming a black hollow and hollow. Control method: use disease-free seeds or resistant and disease-resistant varieties. Seeds should be planted from disease-free or disease-free plants. Carry out rotations and intercropping. Cruciferous vegetables should be rotated with legume vegetables, solanaceous vegetables and food crops, or with garlic. Strengthen field management: 1 timely control of pests and reduce plant wounds. 2 Protected cultivation should avoid excessive humidity in the shed to prevent dripping and condensation. 3 Remove the diseased plant and remove the diseased fruit. When the soft rot disease plant is first seen in the field, it should be removed in time, and the litter is sprayed with lime. Chemical control: 72% agricultural streptomycin sulfate soluble powder 3000 ~ 4000 times liquid, or 1 million units of neo-phytomycin powder 3000 ~ 4000 times liquid spray or root irrigation control. 50% succinic acid copper WP WP 500-700 times solution, or 14% lycopene copper water 300-400 times solution, or 77% can kill WP WP 400-500 times. Fourth, gray mold Symptoms: The cabbage seedlings were killed, initially watery, and then rotted. When wet, there was a gray mold layer on the diseased part. In the adult stage, the leaves that are generally close to the ground first develop, and begin to be water-stained. Later, the lesions are brownish and develop to the base of the stem, and finally rot, causing the upper leaves to wilting; or the leaves extending from the outer leaves to the inner leaves. On, later rotted, and produced a gray mold layer, and sometimes produced a black sclerotia like a rat feces. Cauliflower was killed, mostly from the outer leaves of the yellow or near the lower petiole, and began to appear water-stained. Later, the lesions expanded, and the lesions on the leaves often showed a "V" shape, and finally developed to the leaf or petiole rot. . When the humidity is high, there is a gray mold layer on the diseased part. Control method: 1 Use disease-free seeds and seed hair treatment: use resistant varieties. If the seed is contaminated, it can be soaked in warm soup; 2. Reasonable rotation: Tomato should be implemented with other vegetables such as melons and beans for three years; 3 Strengthen management: remove the residuals of diseased plants and concentrate on treatment; timely topdressing and watering to enhance resistance; 4 chemical control: in the early stage of the disease, timely spraying and prevention. Mechanic Socket Set,Professional Mechanic Socket Set,Mechanic Tool Set Box,Mechanic Tool Chest Set SUZHOU NEWSTAR HARDWARE CO.,LTD. , https://www.hardwarenewstar.com
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