According to the inquiry of Agricultural Resources Network, the efficacy time of closed herbicides is generally related to the types of drugs, the related components of drugs, the quality of pyraclostrobin, water demand, soil moisture and other factors. Taking ipratropium as an example, it can be closed for one month after application, and it can be closed for two months if the soil seedlings are good.

Precautions for using enclosed herbicides are as follows:

(1) You can't take medicine in the high temperature interval at noon. Because people work in hot weather for a long time, it is very easy to take medicine halfway, and pesticides are easy to volatilize and spread rapidly after encountering high temperature, resulting in higher drug concentration in the air than usual, which invisibly enhances the risk of pesticide poisoning.

(2) It is not recommended to take medicine in rainy days. After the drug is mixed with precipitation, it will be diluted twice, which will reduce the concentration of the drug and reduce its efficacy.