Corrosion control of peppers should be the right medicine
JIANGSU ARTSTYLE DECORATION MATERIALS CO..LTD , https://www.artstyledecor.com
July 25 09:57:07, 2025
After entering the rainy season, the high temperature and humidity have created ideal conditions for various diseases to affect pepper crops—both those grown in sheds and those in open fields. As a result, many farmers are facing serious issues such as fruit rot and premature fruit drop, leaving them with few options to manage the problem. According to the **Pesticide Network**, fruit rot in sweet or hot peppers is a common symptom of multiple diseases, but the causes, symptoms, and control methods vary significantly. Below are the main causes and prevention strategies for fruit rot in peppers:
One of the most common issues is sunburn, which occurs when fruits are exposed to direct sunlight. The affected areas turn pale, hard, and develop gray-white leathery spots. Over time, the skin thins, and the flesh becomes necrotic and hard. This damage makes the fruit more susceptible to secondary infections, leading to black mold and eventual rot. To prevent this, timely watering is essential to maintain moisture levels and improve the microclimate. Farmers are also advised to prune by leaving two leaves before removing the growing tip, which helps provide shade and reduce the risk of sunburn.
Another issue is blossom-end rot, which starts as a dark green, water-soaked spot at the base of the fruit. It rapidly expands, causing the area to shrink and sink. The fruit may turn black or become infected with other bacteria, leading to rot. This condition is often caused by high temperatures, drought, and calcium deficiency in the plant. Excessive nitrogen application can further hinder calcium uptake. Studies show that soil with less than 0.2% calcium increases the likelihood of this disease. To manage it, farmers can spray a 1% calcium superphosphate solution or 0.1% calcium chloride solution. If black mold or soft rot develops, additional treatments may be necessary.
Soft rot begins with a dark green, water-soaked spot on the fruit, which eventually leads to complete softening and a foul odor. The internal flesh rots, and the outer layer turns white. The fruit may remain attached to the plant until disturbed. Control measures include spraying 72% streptomycin, 50% DT bactericide, or 40% streptomycin sulfate. Applications should be made every 7 days, up to 2–3 times. Insects like cotton bollworms and tobacco budworm, along with wind and rain, can spread the disease, so it's important to control pests using pyrethroid-based pesticides and protect crops from excessive moisture.
Fruit rot can also start from the stem end, appearing as a water-soaked, gray-green lesion that quickly turns brown and soft. In wet conditions, a white mold may form on the surface, and the fruit may not fall off easily. Other parts of the plant, like stems and leaves, may show similar symptoms. Prevention is key, especially during the seedling stage. Spraying mixtures like 64% anti-virus cockroach and 55% toxic mycorrhizal mixture (30g each per 15L water) or 58% metalaxyl manganese zinc can help. Reapplication every 7 days, up to 2–3 times, is recommended.
Gray mold caused by *Botrytis cinerea* and *Sclerotinia sclerotiorum* is another major concern. These diseases typically appear on young fruits, starting with brown, water-soaked lesions that darken and rot. A gray mold layer forms on the surface. Sclerotinia spreads from the stem to the entire fruit, causing it to soften and turn light gray-brown. These diseases are more common in cold, humid conditions, but can occasionally occur in summer under cloudy weather. The **China Pesticide Network** recommends using products like speed Klein, sclerotium net, or a mixture of 50% keeling and 70% methyl thiophanate (15g each per 15L water). Spraying every 5 days, up to 2–3 times, is effective during outbreaks.
Anthracnose appears when peppers turn red, starting with yellow-brown, water-soaked spots that develop a central gray-brown area with concentric rings. Small black dots may appear, and under wet conditions, a red sticky substance oozes from the lesion. On leaves, the spots start green and later turn brown with a gray center. Control includes spraying chlorothalonil or new Wansheng every 7 days, up to 2–3 times.
Cotton rot causes white mold growth when humidity is high. The fruit rots, and the mold becomes visible. Spraying 50% DT bactericide or 14% lycopene copper water every 7 days can help control it.
Lastly, black mold disease usually affects the top of the fruit first, starting with a lighter color. The fruit shrinks and develops a black-green mold layer, often occurring near maturity. To manage it, spraying 50% DT bactericide diluted 500 times or 58% metalaxyl manganese Zn diluted 400 times, every 7 days, up to 2–3 times, is effective.
By understanding these different types of fruit rot and implementing proper management practices, farmers can better protect their pepper crops and reduce losses.