title: Development of controlled release formulations of carbofuran and evaluation of their efficacy against Meloidogyne incognita.
abstract: Controlled release (CR) formulations of the insecti-nematicide carbofuran have been prepared using commercially available rosin, sodium carboxymethylcellulose and sodium carboxymethylcellulose with clay (bentonite, kaolinite, and Fuller's earth). The kinetics of carbofuran release in soil from the different formulations were studied in comparison with that of the commercially available granules (3G). Release from the commercial formulation was faster than with the new CR formulations. Addition of clay in the biodegradable polymer matrix reduced the rate of release. The diffusion exponent (n value) of carbofuran in soil ranged from 0.462 to 0.740 in the tested formulations. The half-release (t1/2) values ranged between 4.79 and 25.11 days, and the period of optimum availability (POA) of carbofuran ranged from 15.10 to 43.97 days. The mean EC50 of the commercial formulation against Meloidogyne incognita was quite high as compared to those of CR formulations. The effective duration (te) of carbofuran from the CR and commercial formulations was predicted by fitting the mean EC50 values of test formulations in the model (M(infinity) - Me)/M(infinity) = Kdte. It was 0.7 day in commercial 3G in comparison with 17.8 days for CMC-bentonite. The bioassay studies revealed that with the rosin-yellow polymer, the dose of carbofuran could be reduced to half of its recommended dose for nematode control. Overall, a comparison of CR formulations with the commercial one showed an earlier degradation of carbofuran in the latter and relatively prolonged activity in the former.
authors.affiliation: Division of Agricultural Chemicals, Indian Agricultural Research Institute, and Indian Agricultural Statistical Research Institute, New Delhi 110 012, India.
authors.forename: Gunanand
authors.initials: G
authors.lastname: Choudhary
authors.forename: Jitendra
authors.initials: J
authors.lastname: Kumar
authors.forename: Suresh
authors.initials: S
authors.lastname: Walia
authors.forename: Rajender
authors.initials: R
authors.lastname: Parsad
authors.forename: Balraj S
authors.initials: BS
authors.lastname: Parmar
mesh_terms: D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage*; D002235:Carbofuran / Q000008:administration & dosage* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003692:Delayed-Action Preparations; D004058:Diffusion; D007700:Kinetics; D012987:Soil / Q000032:analysis; D013997:Time Factors; D014431:Tylenchoidea / Q000187:drug effects*
chemical_list: D000969:Antinematodal Agents; D003692:Delayed-Action Preparations; D012987:Soil; D002235:Carbofuran