Bioefficacy and persistence of acephate in mungbean Vigna radiata (L.) Wilczek.

The bioefficacy, persistence and metabolism of foliar application of acephate 75 SP at the respective recommended and double doses of 1500 and 3000 g a.i. ha(-1) were studied on kharif mungbean crop. Acephate gave a very effective control of the pod borer, Helicoverpa armigera (Hubner) at the tested doses on mungbean crop throughout the cropping season, besides recording lower percent pod damage and higher grain yield. The recommended dose of acephate also recorded higher net returns and thus indicating its superiority. Persistence of acephate in mungbean leaves and soil was studied following applications of acephate @ 1500 and 3000 g a.i. ha(-1) at 30 days after sowing. Residues of acephate in mungbean leaves and soil were estimated using gas liquid chromatograph (GLC) and confirmed on gas chromatograph-mass spectrometry (GC-MS). Half-life periods for acephate in mungbean leaves were observed to be 2.98 and 3.27 days at single and double the application rates, respectively. Residues of acephate dissipated below its limit of quantification (LOQ) of 0.05 mg kg(-1) after 20 and 25 days at single and double the application dosage, respectively. Similarly, half-life periods for acephate in mungbean soil were observed to be 1.86 and 1.94 days at single and double the application rates, respectively. Residues of acephate dissipated below its LOQ of 0.05 mg kg(-1) after 10 and 15 days at single and double the application dosage, respectively.