What causes spinach leaves to turn yellow, and what are the prevention and control methods?

Spinach is one of the most common vegetables, native to Iran, and is rich in carotene, vitamins and various other nutrients, with high nutritional value. Spinach is grown in most parts of China; it is fairly cold-tolerant and highly adaptable, but many farmers who have grown spinach have encountered the sight of leaves starting to turn yellow as the crop grows. What is going on here? Below, Qinnong Web introduces the causes of yellowing spinach leaves and the corresponding prevention and control measures.

I. Causes of Yellowing Spinach Leaves

There are mainly four causes of yellowing spinach leaves, including normal metabolism, soil problems, fertilizer problems and water problems. Below, Qinnong Web introduces them in detail:

1. Judging normal growth: if new roots grow from the leaf axils of the lower spinach leaves, then the yellowing of the leaves is a normal phenomenon, as this is the spinach's own metabolism.

2. Soil problems: if no new roots grow from the leaf axils of the spinach and the leaves turn yellow, it is mostly due to raw soil, poor air permeability and so on, which cause poor growth of the spinach and yellow leaves. At this time, the soil should be turned over to increase air permeability.

3. Fertilization problems: spinach itself has a ratio of 2:1:3 for the three major elements nitrogen, phosphorus and potassium, which shows that it needs more nitrogen fertilizer and potassium fertilizer, but the amount cannot be increased at will for high yields, nor should a certain fertilizer be applied in a one-sided way. In addition, on soil lacking trace elements such as iron, zinc, manganese and boron, yellow leaves, small leaves, soft rot and other phenomena will also occur, and these can be solved by spraying spinach foliar fertilizer in the later period.

4. Excessive water: watering spinach too much will cause root hypoxia, leading to poor growth and yellow leaves. Generally, for watering, a chopstick can be inserted into the soil to see whether the root area of the spinach is short of water; as long as it is moist, there is no need to water again.

II. Prevention and Control Measures for Yellowing Spinach Leaves

There are mainly two preventive measures for yellowing spinach leaves. Here, Qinnong Web gives everyone a brief introduction from the agricultural and pesticide aspects respectively.

1. Agricultural measures: use seeds harvested from disease-free plants. Lay or hang silver-gray film strips in the field to repel aphids. Clean the field in time, eradicate field weeds, and pull out diseased plants promptly. Choose plots with good ventilation, far from radishes and cucumbers, for planting. Sow at the proper time and avoid sowing too early. In case of spring drought or autumn drought, water more, which can reduce disease incidence. Apply sufficient organic fertilizer and increase phosphorus and potassium fertilizer to enhance the host's disease resistance. For aphid control, aphids must be controlled at the seedling stage, and it is especially necessary before winter.

2. Pesticide control: at the early stage of disease, spray 1.5% Zhibingling emulsion at 1000 times dilution, or 0.5% Kangduji No. 1 aqueous solution at 300 times dilution and other pesticides. For downy mildew and anthracnose, at the early stage of disease, spray 75% chlorothalonil at 600 times dilution, 25% metalaxyl at 700 times dilution, 40% fosetyl-aluminum wettable powder at 300 times dilution and so on for control. For viral diseases, in addition to carrying out crop rotation, aphids and other virus-transmitting vectors should also be controlled in time; during the peak aphid period, 10% imidacloprid at 2000 times dilution or 10% nitenpyram at 3000 times dilution can be sprayed for control.

The above are the causes of yellowing spinach leaves and the related prevention and control methods. After discovering yellowing spinach leaves, everyone should take the initiative to find the cause, then adopt the corresponding prevention and control measures, implement the concept of "prevention first, treatment as supplementary", and produce healthy and high-quality spinach varieties.