10-24℃ (optimal temperature range)
The temperature at which herbicides are used should be determined based on the type, season and environmental conditions. The following are the key points:
Optimal temperature range: The suitable spraying temperature for most herbicides (such as those commonly used in wheat and corn fields) is 10-24℃. At this time, weeds have a strong ability to absorb and transport the agent, and the volatilization of the agent is moderate. Some special agents (such as glyphosate) require a higher temperature (24-30℃) to achieve the best effect.
Low temperature limit:
The average temperature must be ≥6℃ (the daily average calculation method is the average of 2 o'clock, 8 o'clock, 14 o'clock and 20 o'clock). Temperatures below this level are prone to cause pesticide damage or ineffectiveness.
Single spraying requirements: In actual operation, it is necessary to ensure that the instantaneous temperature during spraying is ≥10℃, especially avoid using it in a low temperature environment below 0℃ or 0-7℃.
High temperature limit:
It is not suitable to spray pesticides when the temperature exceeds 28℃, as high temperature will accelerate the evaporation of the pesticide solution, resulting in increased concentration and possibly causing crop damage.
Summer adjustment: It is recommended to spray pesticides before 10 am or after 4 pm to avoid the high temperature at noon.
Season and time period recommendations:
Spring and autumn: Choose 10 am to 3 pm, when the temperature is stable within the appropriate range.
Winter: Spray pesticides only when the temperature reaches the standard at noon.
Dew effect: Spray pesticides after the dew on the leaves is dry to avoid diluting the pesticide.
Other precautions:
Wind speed: It is necessary to operate in a breeze below level 3 to avoid pesticide drift.
Rainfall: No rain within 6 hours after spraying, otherwise re-spraying is required.
Weed growth period: The 2-4 leaf stage is most sensitive to the pesticide and has the best effect.
