Symptoms and Prevention Measures of Bacterial Wilt, a Common Disease of Tomatoes

In recent years, bacterial wilt has become a major disease causing tomato plant death, especially severe in continuous cropping and replanted plots. Bacterial wilt is not easy to detect in its early stages; once symptoms appear, the plant quickly wilts and soon dies, causing yield reduction or even total crop failure for growers. Therefore, many growers are quite troubled by it, “turning pale at the mention of bacterial wilt.” So, what symptoms does bacterial wilt, a common disease of tomatoes have? What are the specific prevention measures?

I. Symptoms of Tomato Bacterial Wilt

Tomato bacterial wilt usually occurs when the plant is flowering and setting fruit. First, the top leaves wilt and droop, then the lower leaves wilt, and the middle leaves wilt last; in some cases, the leaves on one side or the entire plant wilt simultaneously. In the early stage of the disease, diseased plants wilt during the day and recover in the evening. The disease progresses rapidly, and severely affected plants wither and die within 7-8 days.

The pathogen can develop at temperatures of 10-40°C, with the optimum temperature being 30-37°C. The disease is prone to occur under conditions of slightly acidic soil, high temperature and high humidity, continuous cropping, low-lying terrain, poor drainage, potassium fertilizer deficiency, and root damage.

The pathogen spreads through rainwater, irrigation water, underground pests, and farming operations. It invades through the lenticels or wounds on the host's roots or stem base, and spreads upward along the vascular bundles, causing blockage of the vessels. The entire tissue is destroyed and thus loses its transport function. The stems and leaves wilt due to water imbalance.

II. Prevention Measures for Tomato Bacterial Wilt

In essence, tomato bacterial wilt is caused by copper deficiency, so the key to prevention and control is to supplement copper. Secondly, the management of bacterial wilt should prevent spread through flowing water. If there are plants with bacterial wilt, remember not to flood-irrigate; first remove the infected plants from the greenhouse and bury them deeply or burn them. Also note that root drenching should be done before watering.

1. The primary task in treating bacterial wilt is to solve the problem of copper deficiency in the plants. The first watering is the planting water, and the second watering should appropriately add copper-ammonia mixture. A soil pH of 7 is most suitable.

2. A relatively effective method for preventing and controlling bacterial wilt is root drenching with chemicals, but emphasis should be placed on prevention. When choosing chemicals, it is best to choose those with strong systemic activity, such as chlorobromoisocyanuric acid and similar chemicals. For tomatoes that have not yet developed the disease, protective sprays with chemicals such as streptomycin and Kocide 3000 can be used to prevent bacterial wilt.

3. Tomato plants that have already developed the disease and died must not be left in the greenhouse; they should be taken outside and buried deeply. At the same time, the soil should be disinfected (by spreading quicklime powder or plant ash, or by pouring 2% formalin or 20% lime water into the diseased planting holes).

4. In terms of fertilization, pay attention to the rational application of nitrogen fertilizer, and apply more organic fertilizer and phosphorus-potassium fertilizer to enhance the disease resistance of the plants. At the same time, pay attention to cultivating a strong root system in the plants.