Bioefficacy, residue dynamics and safety assessment of the combination fungicide trifloxystrobin 25% + tebuconazole 50%-75 WG in managing early blight of tomato (Lycopersicon esculentum Mill.)

This paper reports the in vitro and in vivo bioefficacy of a combination fungicide trifloxystrobin (25%) + tebuconazole (50%) against early blight disease of tomato (Lycopersicon esculentum Mill.) caused by Alternaria solani and their corresponding pre-harvest intervals (PHI) with reference to the maximum residue limits (European Union). Bioefficacy of the test fungicide combination revealed that in vitro conditions manifested the best control (75.1%) at 350mg kg(-1) against 76.2% control under field conditions. A sample preparation method based on ethyl acetate extraction and estimation by LC-MS multiple reaction monitoring (MRM) was validated in tomato fruits at 0.01mg/kg and dissipation studies were conducted in field at single and double doses. The residues of both the compounds on all the sampling days were below the European Union maximum residue limits (EU-MRLs) and the maximum permissible intakes (MPIs) were calculated on the basis of prescribed acceptable daily intake (ADI). The combined bioefficacy and residue dynamics information will support label-claim of this fungicide combination for the management of early blight in tomato.