Causes and control methods of yellow leaves and dead seedlings of soybean

Farmers often encounter yellow leaves and dead seedlings in the process of planting soybeans, which seriously affect the yield of soybeans and cause huge economic benefits to growers. So what is the reason for soybean yellow leaves and dead seedlings? How to prevent it? Let's take a look at the detailed introduction.

1. Disease

In the seedling stage of soybean infected with top blight disease, its cotyledons will appear brown ring spots, growth node necrosis, in serious cases will die the whole plant; pre-flowering infected planting, its internodes will be extended, the terminal bud will turn brown, the plant will become fragile and easy to fold; post-flowering infected plants, leaves easy to fall off, fewer pods, poor development of pods, delayed maturity, will remain green before harvest.

Prevention and control measures: when the plant is infected, the diseased plant is removed in time to avoid the spread of the disease. For the planting with light disease, the disinfectant alum and chlorothalonil can be sprayed, and the effect is better.

2. Insect pests

Soybean cyst nematode can cause dead seedlings. When seedlings are damaged, leaves will change and develop slowly. In severe cases, plants will wither and die. Adult plants will occur, plants will grow poorly and dwarf, leaves will turn yellow from bottom to top, flowering period will be delayed, pods will not grow full and dark. When the diseased plants are pulled out, soybean cyst nematodes with underdeveloped root system, few nodules and many attached roots will be found.

Control method: increase organic fertilizer, improve soil fertility, promote soybean growth, water timely, keep soil moist, dry soil environment is extremely beneficial to soybean cyst nematode reproduction, low concentration omethoate emulsion can be sprayed on the stem base of the diseased field.

3. Malnutrition

In the lack of fertilizer or partial application of a certain fertilizer plot, or severe drought plot, the plant leaves will appear different yellowing, shrinkage phenomenon, but also to plant growth slow, serious will die because of de-fertilization.

Control methods: scientific and reasonable fertilization to ensure adequate soil fertility, promote soybean growth, for the lack of fertilizer field, can spray low concentration of potassium dihydrogen phosphate solution, can alleviate symptoms or disappear, so that soybean normal growth.

4. Herbicide toxicity

When weeding, if the herbicide is not used properly, the dosage is too high, the herbicide is not matched properly, repeated spraying and other problems, it will cause herbicide phytotoxicity, resulting in yellow leaves of soybean plants, and death seedlings in serious cases.

Control methods: the use of herbicides must be strict scale, found after the phytotoxicity should be timely watering, reduce the concentration of chemicals, spraying foliar fertilizer and plant growth regulators, alleviate phytotoxicity.

The above is the introduction of soybean yellow leaves, dead seedlings and prevention methods, I hope to help you, want to know more related knowledge, please pay attention to us.