Dissipation kinetics, safety evaluation, and decontamination of residues of the combo-formulation iprovalicarb 8.4% + copper oxychloride 40.6% WG in/on grapes (Vitis vinifera L.).

A field experiment was conducted to study the dissipation behavior and decontamination of iprovalicarb and copper oxychloride in grapes. After thorough validation, the analysis was carried out by employing LC-MS/MS for iprovalicarb and AAS for copper oxychloride. The dissipation pattern of residues followed a linear first-order kinetics model for both the test fungicides. The half-life values for iprovalicarb were 9.5-13.5 days, and for copper oxychloride was 24.5 days. Based on the study, a pre-harvest interval (PHI) of 17 days is proposed for the formulation. In decontamination studies, combination treatment of 0.1% sodium bicarbonate + ultrasonication and 2% lemon water + ultrasonication has shown the highest reduction of iprovalicarb (90.02% reduction) and copper oxychloride (80.14% reduction) residues, respectively. The safety evaluation data suggest that the daily exposure at all the sampling points was less than the maximum permissible intake (MPI) calculated indicating, safety to consumers. This study will be useful for promoting effective residue management and the safe use of these chemicals for controlling fungal diseases in grapes.

Physio-biochemical responses of wheat plant towards salicylic acid-chitosan nanoparticles.

Sustained source-activity is imperative for vigor plant growth and yield. In present study, physio-biochemical responses of wheat plant contributing to source-activity were measured after application of salicylic acid-chitosan nanoparticles (SA-CS NPs). SA-CS NPs slowly release SA for sustained availability to plant. In seedling bioassay, as compared with salicylic acid (SA), SA-CS NPs incurred up to ~1.5 folds increased activities of seed reserve food remobilizing enzymes for substantial mobilization of reserve food to growing seedlings and enhanced seedling vigor index (SVI) by 1.6 folds. At booting stage, foliar application of SA-CS NPs (0.01-0.08%; w/v) enhanced the activities of superoxide dismutase (1.94 folds), catalase (1.33 folds), peroxidase (1.99 folds) and polyphenol oxidase (1.04 folds) in flag leaf. SA-CS NPs further contrived cellular homeostasis by comforting reactive oxygen species (ROS), malondialdehyde (MDA) and proline contents in flag leaf. SA-CS NPs (0.08%; w/v) significantly increased chlorophylls (a-b) contents (1.46 folds), spike length without awns, spike lets per spike and grain weight per pot as compared with SA. Study categorically explicates that slow release of SA from SA-CS NPs could exert significant effect on source-activity by maneuvering various physio-biochemical responses of wheat plant.