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Fungicide determination method
Jul 09, 2018

The insecticidal or bactericidal virulence of the agent, commonly referred to as "lethal dose", means that the dose required to kill half (50%) of the biological population (median lethal dose, mg/kg) is often abbreviated as LD50. If the concentration represents a dose, it is "lethal concentration", abbreviated as LC50. The bactericide is expressed as ED50 or EC50, ie the dose or concentration required to inhibit 50% spore germination.

Spore germination assay

Different liquid medicines are sprayed on the surface of the slide or the plate, and the spore suspension is quantitatively added. After the liquid is contacted, the percentage of spore germination is examined by a certain culture time.

Inhibition zone

Mix the suspension of pathogen spores or hyphae with the agar medium, condense, and place a circular filter paper (about 6 mm in diameter) that is sterilized and has different concentrations of liquid in the plane of the medium. After the time, due to the diffusion of the drug solution, the growth of the pathogen is inhibited, that is, a "suppression circle" is formed. The size of the suppression ring was measured to compare the virulence of the biocide.

Growth rate assay

The drug solution was added to the agar medium, and the bacteria were condensed, and after 24 to 48 hours, the colony growth was observed, and the growth rate was calculated and compared with the growth rate of the control group containing no drug.