Greenhouse tomatoes should be careful to prevent navel rot. Matters needing attention in greenhouse tomato planting

Tomato navel rot is the biggest headache for tomato growers. How to prevent and control it to make tomatoes grow better?

1. Symptom Identification

Navel rot can occur in tomatoes from the size of a thumb to before they are ripe. The lesions only occur at the navel of the top of the fruit. The lesions are initially water-soaked dark green, and soon turn into dark brown or black necrotic spots with a diameter of 1 to 2 cm or more. The flesh below rots and shrinks, the navel is sunken, and sometimes cracks. The fruit becomes flat and the flesh becomes sweet. In severe cases, the lesions expand to half of the fruit surface, the fruit stops expanding, turns red early, the skin is soft and dull, and loses its edible value.

2. Causes of navel rot

First, during the fruit expansion period, the water supply is unbalanced, especially in drought conditions, or when the root system's water absorption capacity is weak, the water supply is unbalanced, and the navel of the fruit cannot compete for water, so its growth and development are hindered, forming navel rot; second, calcium deficiency causes physiological disorders in the navel cells, leading to the disease.

3. Conditions that affect the occurrence of navel rot

1. Soil texture: The disease is more serious in areas with strong sandiness, serious water and fertilizer leakage, and heavy salinity.

2. Soil calcium content: The soil contains less calcium and organic acid, especially when the soluble calcium is insufficient, the disease is prone to occur.

3. Growth stage: If there is insufficient water supply during the tomato flowering and fruiting period, or if fertilizer is applied too late, the concentration of soil solution will suddenly increase, and the disease will be more serious.

4. Prevention and control methods: Controlling nitrogen application, balanced fertilization of nitrogen, phosphorus and potassium, and spraying appropriate amounts of calcium on the leaves are all helpful in preventing and controlling the occurrence of navel rot.

1. Apply sufficient base fertilizer when leveling the ground. Add decomposed organic fertilizer and phosphorus and potassium fertilizers to the tomato base fertilizer, such as ordinary calcium and potassium sulfate, or medium-nitrogen, medium-phosphorus and potassium-rich compound fertilizer as base fertilizer.

2. Water at the right time to prevent the soil from being wet or dry, especially avoid excessive drought. Water the first time when planting and the second time when the flowers begin to set fruits. The amount of water should not be too large. Water heavily after the third inflorescence has opened and the first ear of fruit is the size of an egg.

3. Use a combination of foliar and root methods to supplement calcium. Apply calcium fertilizer to the foliage. The 30 days after tomato fruit setting is a critical period for calcium absorption, so spray 1% superphosphate or 0.1% calcium chloride or calcium-containing compound fertilizer on the leaves starting from the early flowering period, spray once every 15 days, and spray 2 to 3 times in succession.