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Abstract The sorption and leaching behavior of kresoxim-methyl was explored in four different soils, viz., clay, sandy loam, loamy sand, and sandy loam (saline), representing vegetables and fruits growing regions of India. Adsorption of kresoxim-methyl in all the soils reached equilibrium within 48 h. The rate constants for adsorption and desorption at two different temperatures were obtained from the Lindstrom model, which simultaneously evaluated adsorption and desorption kinetics. The data for rate constants, activation energies, enthalpy of activation, entropy of activation, and free energy indicated physical adsorption of kresoximmethyl on soil. The relative adsorptivity of the test soils could be attributed to different organic matter and clay contents of the soils. A good fit to the linear and Freundlich isotherms was observed for both adsorption as well as desorption. The groundwater ubiquity score (GUS) for different soils varied between 0 and 2.26. The GUS and leaching study indicated moderately low leaching potential of kresoxim-methyl. The adsorption on four soil types largely depended on the soil physicochemical properties such as organic carbon content, cation-exchange capacity, and texture of the soil. [ABSTRACT FROM AUTHOR]

The rate of degradation of kresoxim methyl and its effect on soil extra-cellular (acid phosphatase, alkaline phosphatase and β-glucosidase) and intra-cellular (dehydrogenase) enzymes were explored in four different soils of India. In all the tested soils, the degradation rate was faster at the beginning, which slowed down with time indicating a non-linear pattern of degradation. Rate of degradation in black soil was fastest followed by saline, brown and red soils, respectively and followed 1st or 1st + 1st order kinetics with half-life ranging between 1–6 days for natural soil and 1–19 days for sterile soils. The rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Although small changes in enzyme activities were observed, kresoxim methyl did not have any significant deleterious effect on the enzymatic activity of the various test soils in long run. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily due to the effect of the incubation period rather than the effect of kresoxim methyl itself. [ABSTRACT FROM AUTHOR]

The article analyzes the degradation kinetics and safety evaluation of residues of buprofezin in grapes and three types of soils of India. It aims at assessing the preharvest interval (PHI) of buprofezin to reduce its residues in grapes and ensure consumer safety. In the study, it was observed that PHI produced the desired result by minimizing buprofezin residues in grapes. As stated, this conclusion can be beneficial to the domestic and export grape industry in India as it complies with the standards of international trade.

The article presents a study about the degradation kinetics and safety evaluation of tetraconazole and difenoconazole residues in grapes. It explores the fungicides' proven bioefficacy against grapevine powdery mildew disease. The authors examined the residue dynamics of two compounds in grapes and the preharvest intervals that correspond to the multiple field applications. They recommended double rates in critical use pattern in Indian viticulture. Residue analysis method was confirmed and tested for trace-level determination of the compounds.

Adsorption of forchlorfenuron on three Indian soils reached equilibrium within 48 h with rate of adsorption being highest on sandy-loam followed by clay and silty-clay soils. The relative adsorptivity of the test soils could be attributed to the different organic matter and clay contents. Desorption rate followed the reverse trend. The rate constants for adsorption and desorption at 298 and 308 K were determined from Lindstrom model, which simultaneously evaluated adsorption and desorption kinetics. The data for rate constants, activation energies, enthalpy of activation, entropy of activation and free energy indicated chemical adsorption of forchlorfenuron on soil. A good fit to the linear and Freundlich isotherms was observed with correlation coefficients >0.97. The groundwater ubiquity score for different soils varied between 1.6 and 2.2, on the basis of which forchlorfenuron could be categorised as a chemical with low to medium leaching category. [ABSTRACT FROM AUTHOR]

Rates of degradation of λ-cyhalothrin and methomyl residues in grape are reported. The dissipation behavior of both insecticides followed first-order rate kinetics with similar patterns at standard and double-dose applications. Residues of λ-cyhalothrin were lost with pre-harvest intervals (PHI) of 12.0–12.5 and 15.0–15.5 days, corresponding to the applications at 25 and 50  g a.i. ha -1 , respectively. In the case of methomyl, residues were lost with PHI of 55.0 and 61.0 days, following applications at 1 and 2  kg a.i. ha -1 , respectively. The PHI, recommended on the basis of the experimental results, was shown to be effective in minimizing residue load of these insecticides below their maximum residue limits (MRLs) in vineyard samples. [ABSTRACT FROM AUTHOR]