In the storage of oranges, more than 20 different diseases can occur, with infectious diseases being the most common. The primary ones include *Penicillium*, followed by green molds, while anthrax, peduncle rot, and black rot tend to appear in the middle and later stages. On the physiological side, edema disease and brown spot disease (also known as cockroach disease) are also significant concerns. Managing citrus rot is a critical challenge during storage and transportation. Based on the main diseases that occur during the storage period, comprehensive prevention and treatment strategies have been developed to help farmers effectively manage mandarin oranges after they’ve undergone anti-corrosion preservation.
Pre-harvest spraying is an essential step. A fungicide should be applied 1-2 times approximately 10 days before harvest to reduce the risk of infection. Common options include 70% thiophanate-methyl wettable powder diluted at 1200-1500 times or 50% carbendazim wettable powder at 1000 times. This helps lower the pathogen load before the fruit is picked.
Timely harvesting is crucial. Oranges should be harvested when they are about 80% mature, depending on the desired storage duration. Harvesting too early or too late can lead to poor storage performance and increased spoilage.
Proper harvesting techniques are equally important. Farmers must follow the "Ten Rules for Harvesting," such as avoiding harvesting during frost, dew, or rain, selecting only healthy fruits, and using gloves or cutting tools to prevent damage. Fruits should be handled gently, avoiding bruising or cuts, which can create entry points for pathogens. Any damaged, fallen, or infested fruits should be separated to avoid contamination.
After harvest, a post-treatment soaking process is recommended. Soaking the fruit in a solution is best done immediately, and the process should not exceed 24 hours. This helps protect the fruit from fungal infections during storage.
Before long-term storage, it’s advisable to ventilate the fruit for 5-7 days. In rainy conditions, this period can be extended to 10-12 days. During this time, the fruit will lose about 3-5% of its weight due to drying, which is normal and beneficial for storage.
Before placing the fruit in the warehouse, the storage area must be disinfected. Sulfur fumigation at 5-10 grams per cubic meter for 1-2 days, or formalin at 30-50 ml per cubic meter for 3-4 days, is effective. The temperature should be maintained between 3-4°C, with humidity around 80-85%, and proper ventilation is essential.
Each fruit should be individually wrapped in agricultural polyvinyl chloride film to provide additional protection against moisture and microbial growth.
Common preservatives include carbendazim (available in 10%, 25%, and 50% concentrations), thiophanate-methyl (in 25%, 50%, and 70% forms), and plant growth regulators like 2,4-D. These agents help extend shelf life but are only effective for short periods, typically until the Spring Festival or when the fruit is consumed.
For sweet oranges, a typical solution might be 25% carbendazim at 500-1000 times dilution, commonly used at 500 times. For 70% thiophanate-methyl, the dilution is usually 700-1000 times, often used at 800 times. 72% 2,4-D butyl ester is typically used at 200-250 ppm. A sample formula could be 50 kg water + 1.2 L of 70% thiophanate-methyl + 18-20 ml of 72% 2,4-D butyl ester.
If 2,4-D butyl ester is unavailable, 2,4-D sodium salt can be used instead. Dissolve 1 g of 85% 2,4-D sodium salt in 80°C hot water, then mix with 4 kg water and 5 g of 70% Topoxine (or 8 g of 25% carbendazim).
For wide-skinned varieties, a solution of 2.5% sodium bicarbonate (NaHCO3) at 40-50 times dilution combined with 200 ppm 2,4-D for 5-10 minutes is effective. A formula could be 50 kg water + 1 kg of 2.5% NaHCO3 + 13 ml of 72% 2,4-D butyl ester. Alternatively, 25% carbendazim at 500 times plus 72% 2,4-D butyl ester at 50-100 ppm can be used.
It's important to use the correct application methods and to prepare fresh solutions daily. If the solution becomes dirty, it should be replaced. Always follow safety guidelines when handling these chemicals. (Yuechi County Bureau of Agriculture)
Health Pills,Sugar Free Chewable Vitamin C,Enervon Sugar Coated Tablet,Flavettes Vitamin C Sugar Free
Jilin Manyitang Pharmaceutical Co., Ltd , https://www.likangpharmaceutical.com