Tomato bacterial spot disease symptoms and prevention methods

In fact, when we grow tomatoes, we often have tomato bacterial spot disease. So how should we better prevent and control it at this time?

pathogen

Pseudomonas syringae pv. tomato

symptom

Tomato bacterial spot mainly harms leaves, stems, flowers, petioles and fruits, especially leaf edges and immature fruits.

The disease is obvious. The leaves are infected, producing dark brown to black spots, often surrounded by yellow halos. The petioles and stems are infected, producing black spots. When young green fruits are infected, small slightly raised spots appear at first. When the fruit is nearly ripe, the tissues surrounding the spots remain green for a long time, which is different from other bacterial spot diseases.

Disease pattern: The pathogen can overwinter in seeds, diseased remains and soil, and spread in the field through rain splash, insects or farming operations such as pruning, forking and harvesting. Multiple reinfections can occur in the field. Seeds with bacteria can also cause long-distance transmission. Wet, cold conditions, low temperature and heavy rain, and sprinkler irrigation are conducive to the disease. Generally, areas with sprinkler irrigation have more severe disease than those with drip irrigation or furrow irrigation.

Prevention and treatment methods

① Agricultural measures: Select disease-resistant varieties. Use drip irrigation in arid areas and avoid using sprinkler irrigation. After harvesting in the field, remove diseased and residual plants in a timely manner, destroy them in a centralized manner, and deep-plow the soil to reduce the source of initial infection.

② Seed disinfection can be carried out by soaking seeds in warm water. Soak the seeds in 55℃ warm water for 30 minutes, then germinate and sow.

③ For chemical control, spray 72% agricultural streptomycin sulfate soluble powder or 4000 times diluted phytosporin, or 400-500 times diluted 77% chloramphenicol wettable powder, or 300 times diluted 14% copper chelate aqueous solution, or 500 times diluted 50% copper succinate wettable powder in the early stage of the disease. Spray once every 7-10 days, and spray 2-3 times in a row.