Causes of jaundice in corn seedlings

Sowing too deep sowing is not easy to emerge, too deep will appear weak seedlings, yellow seedlings, sowing depth should be controlled at 3 ~ 5 cm; while planting, a certain amount of fertilizer can be applied to promote seedling growth.

After the emergence of seedlings and seedlings, the corn should be seeded in 3~4 leaves, and the seedlings should be planted in 6~7 leaves to avoid crowding, competing for water, vying for water, forming weak seedlings, sickness and yellow. Miao; the number of seedlings per mu should be flexibly controlled according to the variety, and the seedlings should be fixed according to the density required by the cultivars.

Insufficient watering before or after sowing, the seeds are not watered enough, and the seeds do not get enough water, which affects the normal germination and emergence. The unearthed time is too long, resulting in weak seedlings and yellowing at the seedling stage.

The water-stained seedlings and water-stained seedlings are often in the rainy season, and the low-lying land is poorly drained or the water is accumulated at the time of wheat harvesting, resulting in yellowing.

Diseases If the seedlings encounter long-term low temperature and rainy weather, it will cause the occurrence and prevalence of corn seedling blight. The seedling blight began to develop in the second and third leaves. The leaves of the seedlings were yellow and dry, and the edges were scorched. The leaves gradually turned yellow and dry from bottom to top; the root hairs were less, and the roots became brown and poorly developed, resulting in weak seedlings. Note that the base of the corn is sprayed with the carbendazim + foliar fertilizer at the beginning of the disease.

Insect pests of maize seedlings mainly include cotton bollworm, golden worm, aphid, armyworm, thrips, swiss squid, ground tiger, plucking sunflower scorpion, etc. The nymphs and female adults are concentrated in the near-surface stalk of corn seedlings. In the base, roots and sheath, the juice is absorbed, so that the damaged corn leaf sheath first turns yellow and dry. Spray with 500~1000 times of 40% phoxim emulsifiable concentrate or 500~1000 times of other systemic insecticides in the base of the stem of corn seedlings or roots; (may also rotate or smash, because ploughing sunflower It only harms gramineous plants.) Other pests can be used with generally high-efficiency and low-toxic insecticides.

Herbicide harms the use of herbicides. A small number of farmers increase the amount of herbicides at will; blindly mix with other pesticides; the concentration of the drug is too high; the sprayers use each other; the effects of counterfeit and herbicides on the post-production will cause corn yellow seedlings.

The deficiency of corn is a zinc-sensitive crop, and white zinc seedlings appear in zinc deficiency, which looks like corn seedling yellow. Generally, zinc fertilizer is better for base application; if zinc deficiency is found during the growth period, it can be used in the seedling stage with 1~2 kg of zinc sulfate mixed with fine soil 10~15 kg, strip application or hole application; or 0.1% zinc sulfate solution ( Note: The concentration should not exceed 0.4%, so as not to cause fat damage. It should be sprayed twice in the interval from the seedling stage to the jointing stage for 7 days, and the fertilizer solution is 60 kg.