• The Korean Journal of Pesticide Science
• /
• v.18 no.3
• /
• pp.156-160
• /
• 2014

The stabilities of four limonoidal substances including azadirachtin A, azadirachtin B, deacetylsalannin and salannin were investigated both in controlled aquatic and soil conditions. The half-life of the total limonoid for neem extracts and its two commercial biopesticides was estimated 86.6-173 days in water under air, while degradation of the compounds was detected below 10% after eight weeks in deoxygenated water. The half-life in dry soil was estimated 43.3-57.7 days, and there was a similar degradation pattern with in aerobic water condition. In case of wet soil condition, the total bacteria of the soils ranged 6-8 log CFU/g soil for during the experiment, and the half-life of the total limonoid was 6.4-12.3 days. From the result, the fast limonoid degradation in wet soil environment was the result of both chemical oxidation and microbial degradation.