Causes, symptoms and control methods of pepper blight

Pepper blight is the most important fungal disease of pepper, which not only harms the roots, stems, branches, leaves and fruits of pepper, but also harms tomato, eggplant, cucumber, melon and other crops, often causing large area plant death, the general field death rate is 20%-30%, serious more than 90%. The following are the symptoms, incidence regularity and control methods of pepper blight:

Chili peppers with blight

1. Symptoms. The blight can occur in the seedling stage and adult stage of pepper, and the stem, leaf and fruit can be infected. When the disease occurs in the seedling stage, the stem base of pepper shows dark green water-immersed soft rot or quenching, which is also called seedling quenching disease. Pepper infection starts from the pedicel, the primary color is dark green water-soaked spots, quickly turn brown and soft rot, when the humidity is high, the infected pepper grows a white mildew layer, and it is a dark brown fruit left on the branch after drying. When the stem is infected, the most common disease is that the plant turns black-brown or black, and the damage to the base of the stem is the most serious. the disease spot is water-immersed at first, and then the brown or black spots expand around the epidermis, and the disease part constricts obviously, resulting in aboveground collapse. It is mainly harmful to adult plants, and the plants wither rapidly.

2. The regularity of the disease. Pepper blight is a fungal soil-borne disease. 30 ℃ is the suitable temperature for the growth and development of Phytophthora blight. The disease is easy to occur after rainy days, with short disease cycle, heavy clay, poor drainage in the field and easy to accumulate water. The land with too much watering and too much watering is also prone to disease. in addition, the planting of pepper plants is too dense, poor ventilation and light transmission, and the disease is serious.

3. Prevention and control measures. Cultivate strong seedlings and reasonably close planting. Strengthen ventilation and dehumidification and reduce the humidity in the shed. Attach importance to the application of organic fertilizer, increase the application of phosphorus and potassium fertilizer, and less nitrogen fertilizer. When a diseased plant of pepper blight is found in the field, it can be sprayed with 72.2% 600-800 times Purek water agent, 64% 500 times antiseptic alum wettable powder solution, or 77% 400-500 times killing wettable powder solution. Prevention and treatment for 4 times in a row. Try to use smoking method or powder spraying method in continuous overcast days, fumigation with 45% chlorothalonil aerosol of 250-300g per mu, and spraying 5% chlorothalonil dust agent of 1kg per mu each time to reduce the humidity in the shed and reduce the further spread and infection of pepper blight.