Murugan A.V.,Central Agricultural Research Institute |
Swarnam T.P.,Central Agricultural Research Institute |
Gnanasambandan S.,Regional Plant Quarantine Station
Environmental Monitoring and Assessment | Year: 2013
Pesticides are shown to have a great effect on soil organisms, but the effect varies with pesticide group and concentration, and is modified by soil organic carbon content and soil texture. In the humid tropical islands of Andaman, India, no systematic study was carried out on pesticide residues in soils of different land uses. The present study used the modified QuEChERS method for multiresidue extraction from soils and detection with a gas chromatograph. DDT and its various metabolites, α-endosulfan, β-endosulfan, endosulfan sulfate, aldrin, and fenvalerate, were detected from the study area. Among the different pesticide groups detected, endosulfan and DDT accounted for 41.7 % each followed by aldrin (16.7 %) and synthetic pyrethroid (8.3 %). A significantly higher concentration of pesticide residues was detected in rice-vegetable grown in the valley followed by rice-fallow and vegetable-fallow in the coastal plains. Soil microbial biomass carbon is negatively correlated with the total pesticide residues in soils, and it varied from 181.2 to 350.6 mg kg-1. Pesticide residues have adversely affected the soil microbial populations, more significantly the bacterial population. The Azotobacter population has decreased to the extent of 51.8 % while actinomycetes were the least affected though accounted for 32 % when compared to the soils with no residue. © 2013 Springer Science+Business Media Dordrecht.
Karuppiah M.,Manonmaniam Sundaranar University |
Rajmohan R.,Regional Plant Quarantine Station
Materials Letters | Year: 2013
Biologically dependable processes for the green synthesis of silver nanoparticles (Ag NPs) were developed in nanoscience and nanotechnology. In this present paper, green synthesis of Ag NPs was performed from aqueous silver nitrate using the fresh Ixora coccinea L., leaves extract. The formation of Ag NPs was observed by the change of color from colorless to dark brown by the addition of silver nitrate into leaves extract. The synthesized Ag NPs were characterized by UV-vis, FTIR and XRD analyses. Further, the size and shapes of Ag NPs were identified by field emission scanning electron microscope (FESEM) technique to obtain particle sizes in the range from 13 to 57 nm. © 2013 Elsevier B.V.
Mandal D.,Regional Plant Quarantine Station |
Bhowmik P.,Regional Plant Quarantine Station |
Chatterjee M.L.,Regional Plant Quarantine Station
Journal of Entomological Research | Year: 2014
A survey was conducted to study the seasonal abundance and effect of weather parameters on cotton mealybug (Phenacoccus solenopsis) on china rose (Hibiscus rosasinensis) in two districts of West Bengal. The population of mealybug in North 24-parganas district showed peak at 12th and 22nd standard week (109.04 and 117.78 per 10 cm shoot length) while at Bankura district peak was at 20th standard week (88.11 and 98.11 mealybugs/10 cm shoot). No population was observed after 34th standard week. P. solenopsis exhibited a significantly positive correlation with maximum temperature (r=0.635 and r=0.704 in North 24-parganas and r=0.756 and r=0.705 in Bankura districts) and significant negative correlation with rain fall (r=-0.502 and r=-0.517 in North 24-parganas and r=-0.510 and r=-0.550 in Bankura districts) during 2011 and 2012 respectively and significant negative correlation with relative humidity (r=-0.538 in north 24-parganas) during 2012.