Prevention and treatment of bacterial angular spot of cucumber

Bacterial angular leaf spot of cucumber is the most common disease of cucumber in daily life. It often occurs simultaneously with downy mildew of cucumber. Because the two diseases are very similar, it is easy to confuse the two diseases if you are not an experienced person. When symptoms appear, you must carefully distinguish them. Otherwise, using the wrong medicine will not only fail to cure the disease, but also cause great harm to the cucumber strips, and even make the cucumber strips moldy and smelly.

In the early stage of cucumber downy mildew, several polygonal water-soaked spots appear on the back of the leaves, while cucumber bacterial angular leaf spot appears on the back of the leaves in the form of needle-shaped water-soaked spots, often with dozens of spots occurring at the same time. The disease development trend is not as rapid as downy mildew, and its impact on cucumber growth is not as serious as downy mildew.

Bacterial angular leaf spot of cucumber is one of the important diseases of cucumber.

Melon strips are often infected by soft rot bacteria, and become yellow-brown, water-soaked and rotten. Angular leaf spot is easily confused with downy mildew, which leads to the wrong medicine being used, making the disease difficult to cure. Generally, there is a black or purple mold layer on the back of the spots on the leaves with downy mildew. The spots do not perforate in the later stage and the melons are not harmed. The spots on the back of the leaves with angular spot disease overflow with pus and perforate, and the melons are harmed and have a foul odor.

The disease is caused by infection with the bacterium Pseudomonas syringae pv. lachrymans. The pathogen overwinters in the soil with diseased remains or in the form of infected seeds, and serves as the source of initial infection the following year. The pathogen on the seeds can survive in the seed coat and inside the seeds for 1 to 2 years. After sowing, it directly infects the cotyledons. The pathogen multiplies between cells and spreads through rain splashes, water droplets falling from the roof, insects, etc. It invades the host through natural openings and wounds. After 7 to 10 days of incubation, lesions appear, and pus is produced when it is humid.

Cucumber bacterial angular spot disease--chemical control:

1. Prevention plan: Add 30ml of "Fine Cut" to 15kg of water and spray evenly on the whole plant. Spray twice every 3 days for the best effect. Dilute and spray, use once every 7 days. When bacterial angular leaf spot and downy mildew occur at the same time, pay attention to the safe interval between the pesticides used.

2. Treatment plan: Add 50ml of "Xijie" + 40ml of "Jinbei" + 5ml of silicone to 15kg of water. In the early stage of the disease, the following pesticides can also be used to treat downy mildew. The above agents can be added and used alternately. Spray once every 7-10 days, and spray 3-4 times in succession. Excessive use of copper preparations can easily cause phytotoxicity and should generally not exceed three times. The spray must be carefully sprayed on the front and back of the leaves to improve the control effect.