When do bananas in Guangdong ripen, and how do you prevent and control diseases after harvest?

Guangdong is one of the main banana-producing regions in China. Specifically, when is the banana ripening time? In addition, many bananas develop some diseases after harvest, affecting the growth of the banana plants. So, how do you prevent and control diseases after banana harvest?

1. When do bananas in Guangdong ripen?

Bananas are tropical plants. In subtropical and tropical regions, they can have a ripening period throughout the year. Bananas ripen on any day of the year, meaning they can be “harvested all year round.” Ripening times differ by region. In China, bananas in Guangdong generally ripen in autumn, while in Hainan they can ripen from February to June each year.

However, special cases cannot be ruled out. Depending on the variety and modern cultivation techniques, there can be multi-season and off-season ripening and harvest.

2. How do you prevent and control diseases after banana harvest?

1. Banana anthracnose

This disease is severe during the yellow-ripe stage of bananas and rarely occurs during the green fruit stage. On infected fruit, just as it turns yellow-ripe, light brown spots the size of mung beans appear on the peel, commonly known as “plum blossom spots.” After 2 days they expand and merge into dark brown spindle-shaped or irregular patches. When humid, many sticky vermilion dots appear on the lesions, and then the entire fruit becomes dark brown and rots. When the stalk is affected, it causes fruit drop, commonly known as “firecracker burn.” This disease is severe on yellow-ripe fruit when summer and autumn temperatures are 25°C to 35°C, and is milder during low-temperature periods in winter and spring. Under conditions of high humidity (above 95%), low O2, and high CO2, it does not develop.

Control method: After budding, spray with a mixed solution of carbendazim at a concentration of one part per thousand and a 200-fold dilution of high-lipid film water emulsion. Apply once every 10 days, 4 times in a row. During the shelf life of 5 days, 90.2% remained disease-free.

2. Banana crown rot

After banana harvest, when stored sealed at 25°C to 33°C for 7 to 10 days, white cotton-like matter appears at the cut surfaces of the hands, causing crown rot. In severe cases, the stalk is also infected, the diseased area turns dark brown, and the fingers fall apart. After 20 to 25 days, the fruit body becomes diseased, the peel splits, and it is covered with white mycelium and Fusarium conidia. The banana flesh becomes hard and is not easy to ripen and turn yellow. The central placenta of green soft bananas is hard, and eating it gives a starchy taste. This disease often occurs in bananas transported north, with severe crown rot rates of 70% to 100% and fruit rot rates of 18.3%. The infection route is through the fruit, mechanical wounds, the fruit axis, and the cut surfaces of the hands. During transport, high temperature and high humidity inside the carriage make the disease develop extremely rapidly.

The preventive method is, after de-handing and washing, to soak the fruit in carbendazim at a concentration of five parts per ten thousand plus a 200-fold high-ester film water emulsion. The preventive effect is above 90%.

3. Banana black spot

Banana black spot is called banana freckle abroad. On infected peel, many raised small black dots are initially scattered or clustered. In severe cases, the fruit axis and fingers are covered with dirty spots and patches. Where the pathogen flows along with water, the disease appears as “old trace bands.” When humid, conidia appear on the small black dots, which appear gray on the outside. After bananas turn yellow-ripe, the small black dots become dark brown, affecting appearance and reducing commercial value.

4. Banana black rot

This disease already occurs in the field. It mostly infects from the fruit stalk or fruit tip. In the early stage the diseased part is black, and in the later stage the whole fruit turns black. When humid, gray-green mycelium appears on the diseased part, the peel becomes leathery, and the rotting flesh gives off a fragrant odor. This disease often occurs during low-temperature periods in winter and spring.

5. Banana sour rot

An occasional disease, often occurring together with freezing injury or CO2 poisoning during storage and transport. Diseased bananas become sour, rot and produce dripping liquid, and a layer of white coarse powdery matter appears on the peel. Liquid from diseased fruit contaminating healthy fruit can transmit the disease. Before harvest, this disease is spread by insects.