Why Do Tomato Leaves Turn Yellow? Latest Causes and Prevention Measures
During tomato cultivation, yellowing leaves are a common phenomenon, sometimes on old leaves, sometimes on young leaves, functional leaves, and heart leaves, and this has a certain impact on tomato yield. So what are the causes of yellow tomato leaves? Let's find out together.
1. Fertilizer and water causes
In daily management, excessive fertilization damages the root system, making it unable to absorb enough nutrients and water to supply plant growth, thus causing leaf yellowing. Improper watering, with a single excessive watering causing waterlogging in the field, very easily leads to root rot and can also cause yellow leaves in tomato plants.
Prevention measures: Watering and fertilization should be reasonable and scientific, watering and fertilizing according to the different growth stages of the plant. Fertilization should pay attention to the balance of nitrogen, phosphorus, and potassium, and excessive application of nitrogen fertilizer should be avoided. At the same time, attention should also be paid to supplementing trace elements to promote normal tomato growth. When watering, avoid flood irrigation, and drain promptly after rain to prevent waterlogging and root rot.
2. Nutrient deficiency
The growth and development of tomatoes cannot do without a variety of trace elements. When the plant lacks trace elements, it will cause physiological diseases. For example, magnesium deficiency causes old leaves to turn yellow; zinc deficiency causes the veins of middle leaves to remain green while the leaf flesh turns yellow; manganese deficiency causes green veins with yellow patches on the leaf flesh; sulfur deficiency causes young leaves to turn yellow.
Prevention measures: In tomato planting management, in addition to applying trace elements in the base fertilizer, foliar fertilizer should also be sprayed in time during the middle and late stages of planting growth to supplement trace elements and reduce the occurrence of physiological diseases.
3. Soil salinization
When tomatoes are cultivated year after year in greenhouses, the base fertilizer is mostly chicken and duck manure plus chemical fertilizers. Over time, this leads to soil salinization, causing the tomato root system growth to be inhibited, and in severe cases may even cause root death, so yellow leaves are actually a relatively mild symptom.
Prevention measures: During the idle period of the greenhouse, remove the film and let heavy rain wash the soil, or use river water and well water for multiple irrigations to press down the salt. When fertilizing, add microbial bacterial fertilizer to regulate the activity of beneficial bacteria in the soil, or apply acidic fertilizer to adjust the pH value.
4. Pests and diseases
Some diseases can also cause yellow tomato leaves, such as some soil-borne diseases and aboveground diseases. Early blight, brown spot disease, and others can all cause yellow leaves. The same is true for pests. When pest damage is severe, it causes leaves to turn yellow. Pests that cause yellow leaves include whiteflies, mites, leafminers, and others.
Prevention measures: For root soil-borne diseases, during the high-temperature crop rotation stage, chemicals can be used to seal the greenhouse at high temperature to treat the soil. For aboveground diseases, spray chemicals in time and treat the specific disease to reduce the incidence rate. For pests, physical control and chemical control can be combined, keeping them within a range that does not affect normal tomato growth.
The above is an introduction to the causes of yellow tomato leaves and prevention measures. We hope it can help you. To learn more related knowledge, please stay tuned to us.