What to Do When Peppers Get Early Blight? Detailed Control Methods
Pepper early blight is caused by the fungus Alternaria solani of the Deuteromycota subphylum, which overwinters as mycelium or conidia in diseased plant debris or on seeds, and spreads through multiple repeated infections via airflow and rainwater. It is prone to outbreak and epidemic at high temperatures of 26-28°C with relative air humidity above 85%. The disease is severe in the hot, rainy summer season in northern regions and in protected cultivation with poor ventilation. Let's take a look at the control methods for pepper early blight below!
Damage Symptoms of Pepper Early Blight
After the pepper stems are affected, brown to dark brown irregular circular or elliptical lesions generally appear at the branching points, with grayish-black mold on the lesion surface. When fruits are affected, it mostly occurs near the calyx, initially appearing as elliptical or irregular brown or black spots that are noticeably sunken; in the later stages, the fruit cracks, the diseased part hardens, and under humid conditions black mold grows on the diseased area. It can also occur at the seedling stage, generally producing dark brown water-soaked lesions at the tips of old leaves or the terminal buds, causing the leaf tips and terminal buds to rot and forming seedlings without growing points; dark green mold layers can be seen on diseased seedlings in the later stage.
Causes of Pepper Early Blight
Pepper early blight is a fungal disease caused by infection with Alternaria solani of the Alternaria genus in the Deuteromycota subphylum. It overwinters as mycelium and conidia with diseased plant debris in the field or on seeds, and produces new conidia the following year, spreading via wind, rainwater, insects, and other means. The pathogen invades through stomata or wounds, and can also directly penetrate the epidermis. The incubation period is 3-4 days, and the diseased area produces large numbers of conidia for secondary infection. When seedlings age and weaken, are too densely planted, with excessive humidity, and poor ventilation and light transmission, the disease is likely to occur. Late transplanting, damp soil, and poor aeration will accelerate the spread of the disease.
Control Methods for Pepper Early Blight
1. Select good varieties: Choose excellent disease-resistant varieties such as Layou No. 4, Layou No. 9, Yuejiao No. 3, Xiangyan No. 9, Yujiao No. 5, etc. Do not grow the same variety year after year; rotate the varieties. At the same time, soak the seeds in warm water at 55°C for 15 minutes to achieve disinfection.
2. Reasonable management: Avoid excessive humidity in the seedbed, and ventilate promptly after watering the seedbed to reduce humidity. For field planting, carry out reasonable crop rotation, plant on high ridges, maintain reasonable planting density, pay attention to ditching and drainage, and prune in a timely manner to facilitate field ventilation, reduce humidity, prevent disease occurrence, and control disease spread. Apply more phosphorus and potassium fertilizers to promote healthy growth of the root system and stems, and enhance disease resistance.
3. Chemical control: In the early stage of the disease, use 75% chlorothalonil wettable powder at 600 times dilution, or 50% iprodione wettable powder at 1000 times dilution, or 64% oxadixyl mancozeb wettable powder at 600 times dilution, etc., used alternately, once every 7-10 days, spraying 2-3 times continuously.