Orchid fungicide-formalin (formaldehyde)

Formalin is colorless and transparent liquid, can be freely miscible with water and ethanol, its aqueous solution is weakly acidic reaction, formaldehyde aqueous solution is volatile at room temperature, and can corrode iron containers. It will aggregate into white precipitate when stored for a long time, which is toxic to humans and animals.

Formaldehyde has strong bactericidal effect and fumigation effect. It is mainly used to treat seedlings, soil and greenhouse disinfection. Generally, it cannot be used as foliar spray. To treat greenhouse soil of seedbed, 2kg of 50-fold liquid medicine or 4kg of 100-fold liquid medicine was used per square meter. When the soil is wet, use 50 times the solution. If the soil water absorption is not strong, can be divided into two applications to avoid loss, after application, the soil surface covered with straw or plastic film to maintain the efficacy. After 1~2 weeks, plant after formaldehyde volatilizes completely, so as not to hurt the roots.

When using, pay attention to: (1) formaldehyde white precipitation, easy to produce phytotoxicity to plants, precipitation after the bottle immersed in water for dozens of minutes, until the white precipitation disappeared;(2) formaldehyde vapor toxic to humans and animals, can not be inhaled, can not be used to clean the hands of liquid medicine wipe eyes. (Liu Zhongjian)