Search Results
Abstract
This contribution is concerned with the investigation of the removal efficiency of the pyridine-based insecticide imidacloprid from aqueous solution irradiated with UV or visible light in the presence of AlFe-pillared clay and Fe-ZSM-5 as catalysts. The obtained results were compared with those achieved using the photo-Fenton reaction as well as TiO2 Degussa P25. A stability study under natural conditions and direct photolysis in the presence of both light sources were also performed.
A simple, rapid, and sensitive high-performance thin-layer chromatographic method has been developed and validated for analysis of residues of imidacloprid, fenitrothion, and parathion in Chinese cabbage. The sample was extracted by sonication in an ultrasonic water bath with acetone-petroleum ether, 5:3 ( v / v ), and the extract was directly applied, as bands, to glass-backed silica gel 60F 254 HPTLC plates. The plates were developed with hexane-acetone, 7 + 3 ( v / v ), in an unsaturated glass twin-trough Camag chamber. Evaluation of the developed HPTLC plates was performed densitometrically with a Camag TLC Scanner 3 controlled by an external PC running Wincats software (Version 1.1.2). The results indicated that the detection limits of imidacloprid ( R F = 0.10), fenitrothion ( R F = 0.59), and parathion ( R F = 0.70) were 5.0 × 10 −9 g, 2.0 × 10 −8 g, 1.0 × 10 −8 g, respectively. Recoveries of the pesticides from Chinese cabbage by use of this analytical method were 80.04–85.22%, and RSD were 4.18–13.15%. The precision and accuracy of the method were generally fit for analysis of pesticide residues in Chinese cabbage.
Imidacloprid is a member of chloronicotinyl neonicotinoid compounds. It is the most important systemic insecticide and has a wide diversity of uses: in agriculture, on turfs, on pets, and for household pests. During the last decade, Forensic Science Laboratories of Maharashtra State, India, detected a large number of human poisoning cases with imidacloprid. Since a large number of biological samples were received for toxicological analysis, thin-layer chromatography (TLC) was the method of choice. This study reports that cobalt thiocyanate was found to be a selective and sensitive spray reagent for imidacloprid in routine analysis by TLC. Imidacloprid reacts with cobalt thiocyanate which gives intense blue-colored compound. The cobalt thiocyanate reagent does not react with the organochlorine insecticides, organophosphorus insecticides, and pyrethroids. Visceral constituents (amino acids, peptides, proteins, etc.) do not interfere.
and consequently improve product quality. Among the various pesticides widely used in fruit and vegetable, the most commonly used broad-spectrum fungicides are carbendazim (CA), thiophanate-methyl (TH) and imidacloprid (IM) [ 1 ]. Although these
The effect of different chemical insecticides, viz. monocrotophos 36 SL, chlorpyriphos 20 EC, triazophos 40 EC, imidacloprid 200 SL, endosulfan 35 EC, Quinalphos 25 EC, Methyl parathion 50 EC and cartap hydrochloride 4 G on natural enemy fauna and their diversity were studied at different crop growth stages, viz. vegetative, maximum tillering and booting in irrigated rice production system of Punjab, India for two wet seasons. Sampling of natural enemy fauna was done at 3 and 10 days after application. Cartap hydrochloride and endosulfan were safe for the natural enemy fauna among different insecticides tested, while in most of observations chlorpyriphos and methy1 parathion were found to be toxic. Natural enemy diversity was maximum in cartap hydrochloride (1.803–1.943), endosulfan (1.437–1.833) and imidacloprid (1.550–1.847) treated plots at all the three phenophases under study. Least diversity was observed in monocrotophos (1.195–1.335), chlorpyriphos (1.002–1.429) and methyl parathion (0.861–1.522) treated plots.
Field studies were undertaken for two consecutive seasons to evaluate the bioefficacy of cyazypyr 10% OD, a new molecule belonging to anthranilic diamide group of insecticides, along with imidacloprid 17.8% SL and fipronil 5% SC as standard checks, against the insect pest complex of tomato vis-à-vis its impact on natural enemies and crop health. The toxicity of cyazypyr 10% OD and four other molecules, each at two doses (diluted in 600l water), against the pupal stage of Trichogramma pretiosum Riley, an important egg parasitoid of Helicoverpa armigera Hubn., was evaluated in the laboratory. Cyazypyr 10% OD @ 90 and 105 g a.i./ha was highly effective in controlling the fruit borer, Helicoverpa armigera Hubn., aphid, Aphis gossypii Glov. and white fly, Bemisia tabaci Gen., and increasing the yield of marketable fruits. This insecticide @ 60-105 g a.i./ha effectively controlled the leaf miner, Liriomyza trifolii Burg. Imidacloprid 17.8% SL @ 22.5 g a.i./ha and fipronil 5% SC @ 60 g a.i./ha were also highly effective in controlling the pests. Considering the bioefficacy and yield, cyazypyr 10% OD @ 90 g a.i./ha may be recommended for effective control of pest complex of tomato. Cyazypyr 10% OD @ 45–105 g a.i./ha did not significantly reduce the field population of natural enemies and was safe to the crop even @ 360 g a.i./ha. In laboratory test, cyazypyr @ 90 and 60 g a.i./ha found to be safe to T. pretiosum Riley pupae, causing only 23.17 and 20.73% mortality, respectively.
The experiments for determining the multiple insect-pest incidence on yield loss in basmati rice was conducted for two crop seasons. Five treatments were, viz. application of imidacloprid in vegetative stage; application of granular insecticide in vegetative stage; application of higher dose of Urea; augmentive releases of yellow stem borer egg mass at vegetative and booting stage; untreated control. During both the years, the correlation between grain yield and dead heart, leaf folder damage and planthopper population at 50 and 65 DAT and white ear at maturity was negative. The analysis of variance of regression analysis of yield Vs damage levels at different crop growth stages during both the years revealed a significant linear relationship. The yield loss was highly related to incidence of stem borer and leaf folder damage at 50 and 65 DAT during both the years. For integrated pest management, effective monitoring of stem borer and leaf folder from 50 to 65 DAT is required, which appeared as a critical crop growth stage. The farmers should remain cautious during this period to prevent yield loss.
Foliar aphid complex is becoming a major constraint of wheat production in India. The only option available to manage them is the use of insecticides. In this endeavor, the All India Coordinated Wheat and Barley Improvement Programme (AICW&BIP) has recommended traditional insecticides viz., dimethoate, oxydemeton methyl etc. Insecticide resistance and dearth of new molecules created a need to identify newer molecules for wheat aphid control. Recently, the neonicotinoids, viz., imidacloprid and thiamethoxam were recommended for the control of foliar aphids by the AICW&BIP. To broaden the base of these molecules, clothianidin, a new molecule, belonging to the neonicotinoids was evaluated at three locations viz., Ludhiana, Karnal and Niphad for two years. It was found that the new molecule was highly effective at 35 g/ha in controlling the foliar aphids and reducing the yield losses. The new molecule was found safe under field conditions but in vitro studies showed that it was relatively toxic to the coccinellid beetles. The feeding preference study showed that the treated leaves were not fed by aphids up to seven days after treatment. No phytotoxicity was observed on the plants even when they were sprayed at very high concentrations.
The study was designed to assess the effect of selected pesticides (metribuzin, glyphosate, imidacloprid, thiamethoxam, hexaconazole, metalaxyl and kitazin) at the recommended and higher rates on plant growth promoting activities of Pseudomonas aeruginosa strain PS1 isolated from mustard (Brassica compestris) rhizosphere. The strain PS1 was specifically chosen owing to its substantial tolerance against pesticides, phosphate solubilization and considerable production of indole acetic acid, siderophores, exo-polysaccharides, HCN and ammonia. Plant growth promoting traits of the strain PS1 decreased consistently as the concentrations of each pesticide was increased from the recommended dose to the higher ones. Generally, the maximum toxicity to plant growth promoting traits was displayed by pesticides at three times the recommended field rate. However, the effect on the plant growth promoting activities of the P. aeruginosa strain PS1 at the recommended dose of each pesticide was less hazardous. This study revealed an additional aspect of the toxicological mechanisms of the pesticides through which they suppress the plant growth.