Determination Method Of Fungicide

The insecticidal or bactericidal virulence of the agent is often expressed as "lethal median dose", that is, the dose (median lethal dose, mg/kg) required to kill half (50%) of the biological population is often abbreviated as LD50. If the concentration represents the dose, it is the "Lethal Medium Concentration", abbreviated as LC50. Fungicides are expressed by ED50 or EC50, that is, the dose or concentration required to inhibit 50% of spore germination.
1. Spore Germination Assay
Spray different medicinal liquids on the surface of glass slides or flat plates, quantitatively add spore suspension, and after contacting the medicinal liquids, check the percentage of spore germination under a microscope after a certain incubation time.
2. Zone of inhibition method
Mix the suspension of pathogenic spores or hyphae with the agar medium, after condensation, place sterilized circular filter paper pieces (about 6 mm in diameter) dipped in different concentrations of medicinal solutions on the surface of the medium, and culture them at a constant temperature for a certain period of time. After a period of time, due to the diffusion of the liquid medicine, the growth of the bacteria is inhibited, that is, an "inhibition zone" is formed. Measure the size of the zone of inhibition to compare the virulence of fungicides.
3. Growth Rate Assay
Add medicinal solution to the agar medium, inoculate the bacteria after condensation, observe the growth of the colony after 24-48 hours, calculate the growth rate, and compare it with the growth rate of the control group without the medicinal agent.