Causes and control of the latest dead seedlings of rapeseed

Rape is the main oil crop, which is widely cultivated in the south and north, and a variety of diseases will occur in the planting process. But at the same time, the lack of rape plants is not caused by the same harm, such as the death of rape seedlings, it may be because of disease, but also because of disease. It may also be due to the physical harm caused by the weather. Now why not take a look at what caused the death of rape seedlings and how to deal with them.

I. the cause of occurrence

1. Insect pest

Aphids eat leaf sap and cause leaf withering and yellowing. In serious cases, the death of seedlings or the serious harm of Pieris rapae and jumping beetles will cause dead seedlings. High temperature, rainy humidity, major virus disease, downy mildew and other diseases will occur in large numbers.

two。 Moisture content

Serious drought in the sowing period, or days of overcast and rain will make the seeds die, and no seedlings will emerge, which is equal to the death of the seedlings. After the seedlings are unearthed, heavy rain or low-lying water will cause stagnant water, which will cause the roots to rot, unable to breathe and die the seedlings. If drought irrigation is not timely, it will cause irreversible loss of water and die, or water at noon on a sunny day during drought, resulting in the phenomenon of boiling seedlings.

3. Density

The planting density is too dense, the growth space of the seedlings is insufficient, the light is not enough, and the underground needs to grab water and nutrition, so some seedlings will appear weak and die gradually for a long time. Or the sowing time is too early, the seeds do not adapt to the temperature after emergence and die suddenly.

II. Preventive measures

1. Prevention of diseases and insect pests

It is found that aphids are sprayed to control, prevent it from sucking leaves, and spread viral diseases. Once a small number of seedlings are found to have downy mildew in the field, we must pay close attention to spraying chemicals to control the occurrence and prevent a large number of germs from multiplying and aggravating the disease.

two。 Water control

Before sowing, take a look at the weather in the recent period of time, and then if you encounter a drought at the seedling stage, be sure to water and flood every evening shortly after the drought to restore growth. In case of heavy rain or continuous rain, it is necessary to check the ditch, timely drainage, prevent stagnant water, sprinkle a certain amount of plant ash moisture absorption to prevent humidity illness.

3. Seedling management

Rape is generally employed in November, so it is OK to raise seedlings in October in advance, do not plant prematurely, and then plant at the growth temperature. When sowing and raising seedlings, we must use seedling trays with well-divided specifications to ensure that each seedling has enough growth space and is not competing for nutrition with each other. Or nursery bed seedlings after the emergence of seedlings and time seedlings, seedlings.

The seedling management from sowing to emergence and then to the seedling stage after transplanting is a fragile period of rape growth, which requires careful management, otherwise the direct death of rape seedlings will consume a lot of time to replenish seedlings and waste manpower and material resources. Generally speaking, prevention should be given priority to, and treatment should be supplemented by good treatment.