Causes of Rotten Apples and the Latest Prevention and Control Methods
Apple is a common fruit, and China is the world's largest apple producer and consumer, with a planting area accounting for more than 40% of the world's total. The larger the planting area, the more problems arise, and rotten apples are one of the more common phenomena, affecting apple yield and quality. So what causes rotten apples? Let's take a look.
1. Diseases
The main cause of rotten apples is disease, and many diseases can cause fruit rot, mainly ring rot, black rot, anthracnose, brown rot, and phytophthora rot. The symptoms of rotten fruit caused by these diseases also differ. For example, ring rot causes ring-shaped lesions on the fruit surface, and as the disease progresses, the lesions expand and cause rot. Black rot causes the rotten area to appear black.
Prevention and control methods: Orchard management should be strengthened. Many diseases continue to cause damage the following year after the pathogens overwinter, so the diseases occur year after year. After harvest, thoroughly clean the orchard, collect weeds, debris, fallen leaves, and residual branches and burn or bury them deeply, then remove diseased and pest-infested branches, broken branches, and withered branches from the trees and take them outside the orchard to burn, reducing the pathogens. When disease is found, remove the diseased fruit promptly to prevent it from spreading to other healthy fruit, and spray chemicals for control.
2. Excessive or too severe girdling
Many fruit growers mistakenly believe that apples cannot achieve high yields without girdling, so they girdle the trees multiple times, not only the main branches but also the auxiliary branches. Combined with failure to apply additional fertilizer in time and improper fertilization, this weakens the trees and gives bacteria and microorganisms an opportunity, causing fruit rot and drop. According to practical production experience, the rotten fruit rate of weak trees can reach 50%, while the rotten fruit rate of robustly growing trees is only within 10%.
Prevention and control methods: During management, excessive girdling should be avoided. Girdling should be done reasonably according to tree vigor and fruit load. After girdling, organic fertilizer and other nutrients should be applied promptly to supplement the plant's nutrition, improve disease resistance, and avoid giving diseases an opportunity. Strong trees should also be cultivated to reduce the fruit cracking rate.
3. High planting density
Rotten fruit mainly occurs because bacteria invade through lenticels, wounds, and other openings. Some fruit growers pursue higher yields, resulting in high planting density, poor air circulation between plants, large branch numbers, and canopy closure between rows and plants. This environment is extremely conducive to the survival and reproduction of bacteria and microorganisms. In addition, spray treatment in this environment is poor, and the fruit surface cannot be evenly covered with chemicals, leaving opportunities for bacterial and microbial infection, thus causing rotten fruit.
Prevention and control methods: Plant reasonably. When canopy closure occurs between plants, prune promptly, removing weak branches, diseased branches, and dense branches to increase air circulation between plants, and spray chemicals to inhibit the growth of bacteria and microorganisms.
4. Long periods of rainy weather
If long periods of rainy weather occur during the fruit expansion stage, the root system absorbs a large amount of water and transports it to the fruit, causing the fruit to expand rapidly and crack. With rain intrusion and bacterial invasion, cracked fruit will turn into rotten fruit. Moreover, after apples are bagged, this phenomenon cannot be avoided either.
Prevention and control methods: During rainy weather, drainage and waterlogging prevention measures should be taken to avoid excessive water absorption by the plants. When bagging, choose high-quality bags with good water repellency and air permeability.
The above are the causes of rotten apples and the prevention and control methods. We hope this helps you. To learn more about apple cultivation, please stay tuned to us.