Corrosion control of peppers should be the right medicine
July 25 10:02:39, 2025
After entering the rainy season, high temperatures and humidity have significantly impacted pepper crops—both those grown in sheds and those in open fields. As a result, many peppers are experiencing fruit rot and premature fruit drop, leaving farmers struggling to find effective solutions. According to the **Pesticide Network**, fruit rot in sweet and hot peppers is a common symptom of various diseases, but the causes, symptoms, and control methods vary depending on the specific pathogen involved. Below are the main causes of fruit rot and recommended prevention strategies for your reference:
One of the most common issues is sunburn disease, which occurs under intense sunlight. The exposed areas of the fruit develop pale, leathery spots that eventually become necrotic and prone to secondary infections. To prevent this, ensure consistent watering to maintain soil moisture and improve the field’s microclimate. Farmers should also prune plants by leaving two leaves before pinching out the growing tip, which helps provide shade and reduce sun damage.
Another condition is blossom end rot, which begins as a dark green, water-soaked spot at the base of the fruit. This area rapidly expands, becomes sunken, and may turn black or rot due to secondary bacterial infections. The primary cause is calcium deficiency, often linked to drought, inconsistent irrigation, or excessive nitrogen application. Soil with less than 0.2% calcium is particularly vulnerable. To manage this, apply 1% calcium superphosphate or 0.1% calcium chloride solution. If black mold or soft rot develops, additional treatments may be required.
Soft rot typically starts as a dark green, water-soaked lesion that spreads quickly, causing the fruit to soften and emit a foul odor. The peel turns white, and the fruit often falls off when touched. Control measures include spraying antibiotics such as 72% streptomycin or 50% DT bactericide, applied every seven days. It's also important to manage pests like cotton bollworms and tobacco budworms using pyrethroid insecticides and protect plants from heavy rain.
Fruit rot caused by infection at the stem end begins with a gray-green, water-soaked lesion that quickly turns brown and soft. In humid conditions, a thin layer of white mold may appear. Affected fruits may not fall off immediately, while other parts of the plant may show similar symptoms. Prevention involves regular applications of fungicides like 64% mancozeb or 58% metalaxyl-manganese, sprayed every seven days.
Gray mold (Botrytis cinerea) and white mold (Sclerotinia sclerotiorum) are also common, especially during cool, wet periods. Symptoms include brown, water-soaked lesions on young fruits, followed by a gray mold layer. These diseases can occur even in summer if conditions are favorable. Recommended treatments include sprays like speed Klein, sclerotium net, or a mixture of 50% carbendazim and 70% thiophanate-methyl. Apply every five days during the outbreak period.
Anthracnose appears when peppers turn red, starting with small yellow-brown spots that develop into gray-brown centers with concentric rings. Under wet conditions, a sticky red substance may ooze from the lesions. Leaves may show similar symptoms. Fungicides like chlorothalonil or new Wansheng are effective, applied every seven days.
Cotton rot causes white mold to appear on the fruit surface when humidity is high. Spraying 50% DT bactericide or 14% copper oxychloride is recommended, applied every seven days.
Black mold disease usually affects the top of the fruit first, leading to a shallow discolored area that gradually shrinks and develops a black-green mold layer. This occurs mainly in mature or nearly mature fruits. Control includes spraying 50% DT bactericide diluted 500 times or 58% metalaxyl-manganese zinc diluted 400 times, repeated every seven days.
By understanding these diseases and implementing timely preventive measures, farmers can significantly reduce losses and improve crop quality. Always follow label instructions when applying pesticides and consider integrating cultural practices to enhance plant health.