Tomato Disease Control Methods and Key Points for Identifying Common Diseases

Tomatoes are susceptible to infection by a variety of pathogens during their growth, and disease control runs through the entire process from seedling raising and transplanting to harvest. Common diseases can be divided by pathogen into three major categories: fungal, bacterial and viral. Among them, early blight, late blight, gray mold and leaf mold mostly occur in rainy, high-humidity environments, bacterial wilt and canker are caused by bacteria, and viral diseases are often spread by insect vectors such as aphids and whiteflies.

Prevention is often more effective than treatment. Before planting, choose varieties with better disease resistance and carry out seed disinfection and soil treatment; during cultivation, practice crop rotation, avoid continuous cropping with solanaceous crops, and maintain reasonable plant and row spacing so the plants get good ventilation and light. For watering, use drip irrigation under plastic film or furrow irrigation as much as possible to reduce prolonged water on the leaf surface; for greenhouse cultivation, also pay attention to timely ventilation and dehumidification.

Field management is equally crucial. Timely pruning and removal of side shoots, removal of old and diseased leaves, and carrying diseased plant residues out of the field for disposal can significantly reduce sources of pathogens. Once a primary diseased plant is found, first make a rough judgment of the disease type, then choose the right pesticide for the symptoms; the direction of medication for fungal, bacterial and viral diseases differs, and blind mixing tends to waste the window for control.

It should also be noted that blossom-end rot is mostly caused by calcium deficiency or water imbalance and is a physiological problem; spraying fungicides alone has no effect, and it should be improved through water and fertilizer management. High temperature and high humidity after rain are a period of high disease incidence, so field inspections should be strengthened, medication should be applied promptly at the early stage of disease onset, and pesticides should be rotated to delay the development of resistance, so that losses can be kept to a relatively low level.