Co2 Fire Extinguisher,Co2 Powder Fire Extinguisher,Carbon Dioxide Extinguisher,A Carbon Dioxide Extinguisher JIANGSU NEW FIRE FIGHTING TECHNOLOGY CO.,LTD , https://www.newayfire.com
Bacterial blight is a severe disease that affects both spring and summer sowing cucumbers. It primarily targets the stems and leaves, causing significant damage to the crop. On the stems and lower parts, small, round or elongated yellow-brown lesions appear, which are oily in appearance and slightly sunken. These lesions exude amber-colored gum, and black spots can be seen on their surface. When the disease affects the leaves, large, irregular brown spots develop. Some of these lesions start from the leaf edges and spread inward, forming V-shaped or semi-circular patterns. As the disease progresses, the lesions become brittle and may break apart. Black dots are often found within the affected areas. The size of the leaf lesions varies, ranging from 10 to 35 cm in diameter, with some being even larger. Affected leaves turn yellow from the bottom but do not fall off easily. In severe cases, only the top 1–2 leaves remain. Unlike wilt diseases, bacterial blight does not cause discoloration of the vascular bundles, nor does it kill the entire plant, making this an important distinguishing feature.
The disease is caused by various bacterial pathogens, including spores and ascospores of winter wheat. These pathogens overwinter in infected plant debris and soil, and are mainly spread through irrigation water and wind. They enter the plant through stomata, lenticels, or wounds. Infected seeds can also lead to cotyledon infection. Factors such as high temperature and humidity, poor ventilation, excessive nitrogen fertilizer use, flat vine growth, flood irrigation, heavy rainfall, weak plant growth, and repeated cultivation in the same area increase the risk of infection.
To prevent bacterial blight, several measures can be taken. First, practice crop rotation for at least 2–3 years and select disease-free seeds or plants. Second, focus on cultivating strong seedlings by increasing phosphorus and potassium fertilizers to boost plant resistance. Improve air circulation and light exposure, reduce temperature and humidity, and enhance the overall field microclimate. Third, apply chemical treatments early in the disease cycle. Options include 75% chlorothalonil wettable powder diluted at 600 times, 70% thiophanate methyl wettable powder at 800 times, 50% carbendazim wettable powder at 1500 times, or 45% chlorothalonil smoke agent at 250 grams per acre. Another option is 40% Fuxing Star emulsifiable concentrate diluted at 800 times. Apply these treatments every 7–10 days, repeating the process 3–4 times for effective control.