How to Control Tomato Diseases

In fact, when we grow tomatoes, various diseases will appear, which is really a headache. So how can we better prevent and control them?

1. Large deformed fruit

Large deformed fruits are mainly produced during the differentiation and development period of flower buds, that is, under the conditions of low temperature, high fertilizer, especially excessive nitrogen nutrition, and sufficient light, the growth point accumulates too much nutrition, the developing flower bud cells divide too vigorously, the number of carpels is too large, and after flowering, due to the uneven development of each carpel, multi-chambered deformed fruits are formed. Therefore, in production, it is advisable to choose varieties that are not easy to produce deformed fruits, remove deformed fruits in time, the temperature should not be controlled too low during seedling cultivation, and the water and nutrition should also be adjusted appropriately.

2. Tomato navel rot

The top of the fruit rots, turns dark brown, and the tissue is sunken. When the humidity is high, black mold appears on the lesions, and the diseased fruit turns red early, but has no commercial value. The main reason for the occurrence is calcium deficiency. Abnormal water supply during the growth period can also cause navel rot. Measures to prevent navel rot are: apply lime to adjust acidic soil, pay attention to maintaining the appropriate soil concentration when fertilizing, do not apply excessive chemical fertilizers, and increase the application of organic fertilizers to improve the physical and chemical properties of the soil; try to avoid drastic changes in soil temperature and humidity; after fruit setting, spray the leaves with 0.4-0.5% calcium chloride or 1% superphosphate, 0.1% calcium nitrate and 6000 times of Aiduoshou liquid in plots prone to navel rot, starting from the initial flowering period, once every half a month, and spray twice in a row.

3. Tomato hollow fruit

Hollow fruit is a fruit with a hollow between the peel and the jelly-like pulp. There are two main reasons for the occurrence of hollow fruit: one is that when flowering, it encounters low temperature, which cannot be fertilized normally, forming hollow fruit. The other is that when growth hormone is used, hollow fruit is formed due to excessive concentration or improper treatment during the bud stage. In addition, hollow fruit will also appear due to insufficient light, excessive temperature during the young fruit stage, insufficient nutrition in the later stage, and improper watering during the fruiting period. The prevention and control measures are: strictly control the temperature during the flowering period of tomatoes, the suitable temperature during the day is 20-30℃, and 15-20℃ at night. Reasonable use of growth regulators, that is, the method and concentration of hormone treatment should be appropriate. Generally, 15-20 mg/kg of anti-drop agent is sprayed during the flowering period to prevent flower drop. After hormone treatment, fertilizer and water management should be strengthened. Use formula fertilization technology to reasonably increase the application of nitrogen, phosphorus and potassium fertilizers.

4. Dead Fruit

Dead fruit is also called bean fruit. After fruiting, it basically does not develop. It is as small as a bean or as big as a thumb. It is dead and seedless. The main reasons for its occurrence are too high or too low temperature, poor pollination and fertilization, insufficient light, insufficient supply of nutrients required for fruit expansion, or many external conditions and internal factors that make the fruit unable to absorb and utilize nutrients and show symptoms. The prevention and control measures are: ① Carry out artificial assisted pollination. ② Use tomato spirit to dip the flowers. It has been observed that in greenhouse cultivation in severe winter, dead fruit is prone to occur in the late stage of fruit growth, especially in long-term cloudy and snowy weather, weak light, high night temperature, less nutrients produced by leaves during the day, and large consumption at night, which is also easy to form dead fruit. In this case, light can be supplemented at night to reduce the night temperature to 7-10℃, maintain the minimum growth temperature, reduce consumption, and reduce dead fruit.

5. Fruit cracking

Some cracked fruits are centered on the fruit stem and split in concentric circles, some crack radially with the fruit stem as the center, and some crack sideways and crack the skin irregularly. The physiological reason for cracking is that the fruit skin lacks elasticity and cannot withstand the strong turgor pressure from the inside of the fruit. Especially under the conditions of high temperature, strong light and dry soil at the early stage of fruit expansion, the fruit expands rapidly and cracks occur. For prevention and control, it is advisable to select crack-resistant varieties, prevent the soil from getting wet suddenly after drying; avoid direct strong light exposure to the fruit; increase the application of boron fertilizer to enhance the reversibility of the fruit skin.

6. Tomato sunburn

In hot seasons or under high temperature conditions, due to strong direct sunlight, the temperature of the fruit shoulder rises, some tissues are scalded and die, and sunburn occurs. The prevention and control measures are: use cone racks or herringbone racks, move the fruit ears to the shade of leaves inside the racks when tying seedlings, prune branches in time to ensure that the plant leaves are lush, and prevent strong sunlight from directly hitting the fruit. Appropriate potassium fertilizers are applied to enhance its resistance.