Persistence and risk assessment of emamectin benzoate residues on okra fruits and soil

Abstract

Emamectin benzoate, a synthetic derivative of abamectin, is found effective against fruit borer and jassid in okra crops. The present studies were carried out to study the dissipation pattern of emamectin benzoate on okra and to suggest a suitable waiting period for the safety of consumers. Following three applications of emamectin benzoate (Proclaim 5 SG) at 68.1 and 136.2 g a.i. ha⁻¹, the average initial deposits of emamectin benzoate were observed to be 0.22 and 0.42 mg kg⁻¹, respectively. These residues dissipated below the limit of quantification (LOQ) of 0.05 mg kg⁻¹ after 5 days at both the dosages. Soil samples collected after 15 days did not reveal the presence of emamectin benzoate at LOQ of 0.05 mg kg⁻¹. Acceptable daily intake (ADI) of emamectin benzoate is 0.0005 mg kg⁻¹ body weight day⁻¹, which means an adult of 55 kg weight can safely tolerate an intake of 27.50 μg emamectin benzoate. Assuming an average consumption of 80 g okra fruit and multiplying it by average and maximum residues observed on 0 day at recommended dosage, the intake of emamectin benzoate comes out to be about 20 μg and these values are quite safe in comparison to its ADI. These studies, therefore, suggest that the use of emamectin benzoate at the minimum effective dosages do not seem to pose any hazards to the consumers if a waiting period of 1 day is observed.

Keywords:

• residues
• dissipation
• half-life
• acceptable daily intake
• waiting period

Acknowledgement

The authors are thankful to the Head, Department of Entomology, PAU, Ludhiana, for providing necessary research facilities to carry out these studies.