Why does fruit rot easily after grapes are bagged?
Bagging grapes is an important step in grape growing. But many grower friends report that grapes rot easily after bagging. What exactly is the reason? Below, the editors of Tuliu Network will walk you through an analysis~
1. Wrong bagging time
Relatively speaking, bagging grapes earlier is better, but too early is also not good. Generally, bagging is done during the swelling stage. If bagging is late, some grapes have already been infected with pathogens, and spraying medicine will find it hard to kill the pathogens. According to experiments, bagging during the swelling stage resulted in a grape rot rate of only 2.5%, while grapes bagged 20 days later had a rot rate as high as 17.8%.
2. Wrong bagging method
Practice has proven that after spraying grapes with medicine, you should wait for the liquid to dry and then promptly finish bagging, preferably all on the same day. If there is no rain and no dew at night, finishing within two days is also acceptable, but it is not as good as finishing on the same day. If the grape area is large, it can be divided into blocks, and based on labor and bagging speed, calculate the number of bags that can be done in 1 day; spray only as much medicine as you can bag. Do not spray medicine and then bag immediately without waiting for the liquid to dry, because this easily causes fruit rot. You must also note that when bagging, try to avoid touching the berries with your hands, and be sure to tie the upper opening of the bag tightly to prevent rainwater from leaking in.
3. Improper spraying method
First, the spraying time is wrong. Do not spray when strong winds are blowing. It is best to spray between 7 and 10 a.m., which avoids dew and strong light exposure and helps finish bagging on the same day. Second, spraying is uneven. When spraying, do not spray too much medicine, and even more so do not miss spraying. For trellised grapes, both sides must be sprayed, and for overhead trellises, both sides of the clusters must also be sprayed. Third, there is the issue of choosing medicine. You should choose good-quality medicines, such as mancozeb, thiophanate-methyl, DuPont Fuxing, etc. In addition, the sprayer nozzle should use a fine swirl plate to help make the spray fine and even.
4. Paper bag quality issues
Paper bags produced by some informal manufacturers using inferior raw materials, paper bags made at home from newspaper, and paper bags that have been used once will all cause fruit rot inside the bag. You should buy standard qualified wood pulp paper bags. Although they are a bit more expensive, they are safe and reliable.
Alright, the above are the reasons for fruit rot after bagging grapes brought to you by the editors of Tuliu Network. We hope it is helpful to everyone. That is all for today, and we will see you next time.