Persistence and dissipation of flubendiamide and its risk assessment on gherkin (Cucumis anguria L.)

A supervised open field trial was conducted to evaluate the dissipation pattern and risk assessment of flubendiamide in gherkin fruits following foliar application of Fame 480 SC at 60 and 120 g a.i.?ha^?1. Samples of gherkin fruits were drawn at different time intervals and quantified by HPLC-DAD. The maximum initial deposits of flubendiamide on gherkin were found to be 0.79 and 1.52 mg kg^?1, respectively, at recommended and double the recommended doses. The dissipation pattern of flubendiamide followed a first-order kinetics with half-lives of 1.87 to 2.16 days at 60 and 120 g a.i.?ha^?1, respectively. The limit of quantification of flubendiamide and desiodo flubendiamide was observed to be 0.01 mg kg^?1 for gherkin fruit and soil substrates. Theoretical maximum residue contribution (TMRC) for flubendiamide was calculated and found to be well below the maximum permissible intake (MPI) on gherkin fruits. Thus, the application of flubendiamide at the recommended dose on gherkin fruits presents no human health risks and safe to consumers.     

Impact assessment of pesticide residues in fish of Ganga river around Kolkata in West Bengal

An investigation was conducted from 2001 to 2005 for determining the residual concentration of five pesticides, viz., total-HCH, total-DDT, total-Endosulfan, Dimethoate and Malathion in fish samples collected from various points of the river Ganga. Fish samples were analyzed for pesticide residues using standard laboratory procedures by GC method. It was found that total-HCH concentration remains above the MRL values for maximum number of times in comparison to four other pesticides. The pesticide contamination to fish may be due to indiscriminate discharge of polluted and untreated sewage-sludge to the river. The pesticide contents in some places are alarming. Thus proper care, maintenance, treatment and disposal of sewage water and sludge are most vital and should be the prime thrust for the nation.     

Biomass and nutrient concentration of sweet corn roots and shoots under organic amendments application

Two field experiments were conducted at the Waimanalo research station on the island of O'ahu, Hawaii to study the effect of chicken (CM) and dairy (DM) manures on biomass and nutrient concentration in sweet corn roots and shoots. Sweet corn (super sweet 10, Zea Mays L. subsp. mays) was grown for two consecutive growing seasons under four rates of application (0, 168, 337, and 672 kg ha^{? 1} total N equivalent) and one time (OTA) or two time (TTA) applications of organic manure types and rates. There were significant effects of types, rates, and number of manure applications on dry biomass and macro- and micro-nutrient concentration in roots and shoots tissues. Results of root tissue indicated a significant accumulation of N and C under CM and DM treatments compared with the control treatment. Manure application rates significantly increased the accumulation of N and C in root tissue. Dry weight of roots and shoots and both macro- and micro-nutrient contents in the plant tissues significantly increased under TTA treatment compared with OTA treatment. There was a significant correlation (r² = 0.46 to 0.81) between root biomass, macro-, and micro-nutrient contents during both growing seasons. The results of the study indicates that amending soils with CM at the highest application rate provided the best crop performance in terms of root and shoot biomass, crop N, C, and other macro- and micro-nutrients.     

Determination of fluopicolide in grapes and soil using an easy sample preparation method and gas chromatography-mass spectrometry

A simple analytical method was developed and validated to determine fluopicolide residues in grapes and soil using the “Quick, Easy, Cheap, Effective, Rugged and Safe” approach followed by gas chromatography-mass spectrometry in the selected ion monitoring mode. Fluopicolide residues were extracted from grape and soil samples with acetonitrile, and the extracts were cleaned up by dispersive solid-phase extraction with primary secondary amine sorbent. The limit of quantification was 0.02 mg kg^?1 with grape and soil samples spiked at three levels, and recoveries were from 95% to 101% and 94% to 101% with relative standard deviations from 0.2% to 4.4%. The method is less expensive and safer than existing analytical methods for grapes and soil.     

Soil pH and anion abundance affects on copper adsorption

Copper (Cu) input to agricultural soils results from Cu containing pesticides and or that in soil amendments, such as manure or sewage sludge. Soil and soil solution properties influence the adsorption and desorption of Cu by the soil, which in turn determines its plant availability and/or phytotoxicities. Effects of different anion enrichment in the equilibrium solution on Cu adsorption by different soils (pH range of 6.2-9.9) were investigated in this study over a range of Cu concentrations. With Cu concentrations in the range of 0-100 mg L(-1) in the equilibration solution, 95-99% of applied Cu was adsorbed by all three soils. The adsorption of Cu was similar regardless of using either 0.01 M CaCl2 or Ca(NO3)2 as the equilibration solution. When the Cu concentration in the equilibration solution was further increased in the range of 500-2000 mg L(-1), the adsorption of Cu decreased from 60 to 24% of applied Cu in two soils with pH 6.2-7.9. In a high pH soil (pH=9.9), the Cu adsorption decreased from 77 to 34%. Addition of incinerated sewage sludge (ISS) to a Palouse silt loam soil (pH = 6.2) increased the Cu adsorption as compared to that by unamended soil. This was, in part, due to an increase in the soil suspension pH with ISS amendment.     

Effect of natural preservatives on the growth of histamine producing bacteria

Present study deals with the hampering of the growth of histamine producing bacteria (HPB), by using NaCl and spices which are easily available and cheaper cost wise. For this experiment, four strains of HPB viz. Vibrio parahaemolyticus, Bacillus cereus, Pseudomonas aeruginosa and Proteus mirabilis were tested against 1 to 10% concentrations of NaCl and 1 to 5% concentrations of natural preservatives (turmeric, ginger and garlic) in a basal medium. HPB showed different growth rates at different concentrations of NaCl and natural preservatives. V. parahaemolyticus, B. cereus and Ps. aeruginosa showed no growth at 10% concentration. When the HPB growth was tested with garlic, turmeric and ginger extracts, growth of all the bacteria was inhibited by garlic and turmeric extracts at 5% concentration. In ginger, V. parahaemolyticus, B. cereus and P. mirabilis were totally inhibited at 5% concentration. But Ps. aeruginosa showed very less growth at this concentration.     

Community structure and coral status across reef fishing intensity gradients in Palk Bay reef,southeast coast of India

Coral reef fishes are exploited without the knowledge of their sustainability and their possible effect in altering the community structure of a coral reef ecosystem. Alteration of the community structure could cause a decline in the health of coral reefs and its services. We documented the coral community structure, status of live corals and reef fish assemblages in Palk Bay at the reef fishing hotspots and its nearby reef area with minimum fishing pressure and compared it with a control reef area where reef fishing was banned for more than two decades. The comparison was based on the percent cover of different forms of live corals, their diversity and the density and diversity of reef fishes. The reef fish stock in the reef fishing hotspots and its neighbouring reef was lower by 61 and 38 %, respectively compared to the control reef. The herbivore fish Scarus ghobban and Siganus javus were exploited at a rate of 250 and 105 kg month^?1 fishermen^?1, respectively, relatively high comparing the small reef area. Live and dead corals colonized by turf algae were predominant in both the reef fishing hotspots and its nearby coral ecosystems. The percent cover of healthy live corals and live corals colonized by turf algae was <10 and >80 %, respectively, in the intensively fished coral ecosystems. The corals were less diverse and the massive Porites and Favia colonies were abundant in the intensive reef fishing sites. Results of this study suggest that the impact of reef fish exploitation was not solely restricted to the intensively fished reefs, but also to the nearby reefs which play a critical role in the resilience of degraded reef ecosystems.