Why not use pesticides in high humidity weather?

High humidity is different from the scouring effect of rain, which mainly causes the mechanical loss of chemicals, while humidity mainly causes the chemical decomposition of chemicals, making chemicals ineffective or causing phytotoxicity. For example, when the air is humid, foggy and dewy, don't use Bordeaux mixture. Due to the contact of these chemicals with high humidity air and the action of carbonic acid gas, it is easy to increase the water-soluble dosage and increase the phytotoxicity. Moreover, humidity is often related to temperature. Many pesticides decompose at high temperature, which can catalyze decomposition (while microbial pesticides can exert their efficacy better at high temperature).