Evaluation of mycobacillin and versicolin as agricultural fungicides. II. Stability in soil.

The effect of paddy soils on mycobacillin and versicolin was investigated. Soil inactivated mycobacillin as determined by spectral analysis and microbiological assay. Soil can inactive mycobacillin only at or above the threshold concentration (125 approximately 130 mug per 10 mg of soil), the excess being unreacted. No new peak appears in the ultraviolet spectrum (240 approximately 300 nm) while mycobacillin is inactivated. Soil is without any effect on versicolin.