Concentrations Of Imidacloprid Research Articles

IMIDACLOPRID TOXICITY AND ITS ATTENUATION BY AQUEOUS EXTRACT OF MORINGA OLEIFERA LEAF IN ZEBRA FISH, DANIO RERIO

Objective: Imidacloprid (IMC) is a systemic chloro-nicotinyl insecticide that is applied in crop fields to control a wide variety of harmful insects and pests. The objective of the present study was to evaluate the mitigating effects of Moringa leaf extract (MLE) against Imidacloprid (IMC) induced mortality after acute toxicity bioassay in zebrafish, Danio rerio.
 Methods: The fishes were exposed to various concentrations of IMC to estimate the LC50 values at different exposure periods using the probit analysis.
 To assess the attenuating effect on mortality fishes were exposed to different concentrations of MLE along with 24 and 96 h LC50 of IMC. Mortality rate of fishes was recorded during all experimental periods.
 Results: The LC50 values were found to be 0.423, 0.352, 0.297 and 0.270 ml/l after 24, 48, 72 and 96 h respectively. The upper confidence limits were 0.491, 0.408, 0.334 and 0.302 ml/l and lower confidence limits were 0.355, 0.296, 0.260 and 0.238 ml/l for 24, 48, 72 and 96 h respectively.
 The fishes remain alive at 12 ml/l and 10 ml/l of MLE against 24 and 96 h LC50 respectively. Some behavioral responses such as violent, sluggish and erratic movement, respiratory distress, mucous secretion all over the body, discoloration were also observed in IMC treated fishes in comparison to MLE treated fishes.
 Conclusion: These findings demonstrated that MLE has mitigating effects against the toxic influence of IMC on mortality in zebra fishes which is attributed to its antioxidant effects.

Population growth of Brachionus calyciflorus affected by deltamethrin and imidacloprid insecticides

Rotifers due to their relatively short lifespan, high fecundity and high rate of population increase are ideal for chronic toxicity tests. The aim of this research was determine the lethal concentrations (LC50 24 h) of deltamethrin and imidaclopride and their impacts on reproduction and growth of the freshwater rotifer, Brachionus calyciflorus. Experiments carried out statically based on standard method (O.E.C.D.). Based on LC50 levels of pesticides, different concentration treatment groups designated and rotifer population responses in the five different concentrations of deltamethrin (0.00, 0.05, 0.10, 0.21 and 0.53 mgl-1) and imidacloprid (0.00, 6.22, 12.45, 24.91 and 62.27 mg l-1) with three replicates per each concentration during ten days were studied. The LC50 24h of deltamethrin and imidacloprid for freshwater rotifer determined as 1.06 mg l-1 and 124.54 mg l-1, respectively. The density of rotifers in all treatment groups of pesticides compare to the control group at tenth day decreased significantly (p<0.05). The ovigerous females to nonovigerous females ratio (OF/NOF) and mictic females to amictic females ratio (mic/amic) significantly affected (p<0.05) in all concentrations for both insecticides. This study suggested that B. calyciflorus are severely sensitive to deltamethrin rather than to imidacloprid pesticide.

Comparison of the Relative Efficacies of Granulated Activated Carbon and Biochar to Reduce Chlorpyrifos and Imidacloprid Loading and Toxicity Using Laboratory Bench Scale Experiments.

Pesticide loads and associated toxicity can be significantly reduced using integrated vegetated treatment systems, which remove moderately soluble and hydrophobic pesticides, but need a sorbent material to remove more soluble pesticides. Neonicotinoids such as imidacloprid are widely used insecticides, acutely toxic, and have been linked to a range of ecological effects. Laboratory experiments were conducted to test the sorptive capacity of granulated activated carbon and biochar for removing imidacloprid and the organophosphate insecticide chlorpyrifos in a scaled-down treatment system. Simulated irrigation water spiked with individual pesticides was treated with a bench-top system designed to mimic a 600 L carbon installation receiving 108,000 L of flow per day for sixteen days. Biochar reduced insecticides to less than detectable and non-toxic levels. Granulated activated carbon similarly reduced chlorpyrifos, but allowed increasing concentrations of imidacloprid to break through. Both media treated environmentally relevant concentrations, and would be effective if used under conditions with reduced particle loads.

Enhanced cytotoxicity of imidacloprid by biotransformation in isolated hepatocytes and perfused rat liver

Imidacloprid (IMD) is a neonicotinoid insecticide widely used in crops, pets, and on farm animals for pest control, which can cause hepatotoxicity in animals and humans. In a previous study using isolated rat liver mitochondria, we observed that IMD inhibited the activity of FoF1-ATP synthase. The aim of this study was to evaluate the effects of IMD on rat isolated hepatocytes and perfused rat liver, besides the influence of its biotransformation on the toxicological potential. For the latter goal, rats were pretreated with dexamethasone or phenobarbital, two classical cytochrome P-450 stimulators, before hepatocytes isolation or liver perfusion. IMD (150 and 200 μM) reduced state 3 mitochondrial respiration in digitonin-permeabilized cells that were energized with glutamate plus malate but did not dissipate the mitochondrial membrane potential. In intact (non-permeabilized) hepatocytes, the intracellular ATP concentration and cell viability were reduced when high IMD concentrations were used (1.5–3.0 mM), and only in cells isolated from dexamethasone-pretreated rats, revealing that IMD biotransformation increases its toxicity and that IMD itself affects isolated mitochondria or mitochondria in permeabilized hepatocytes in concentrations that do not affect mitochondrial function in intact hepatocytes. Coherently, in the prefused liver, IMD (150 and 250 μM) inhibited gluconeogenesis from alanine, but without affecting oxygen consumption and urea production, indicating that such effect was not of mitochondrial origin. The gluconeogenesis inhibition was incomplete and occurred only when the rats were pretreated with phenobarbital, signs that IMD biotransformation was involved in the observed effect. Our findings reveal that changes in hepatic energy metabolism may be acutely implicated in the hepatotoxicity of IMD only when animals and humans are exposed to high levels of this compound, and that IMD metabolites seem to be the main cause for its toxicity.

Study on Anodic Oxidation parameters for removal of pesticide Imidacloprid on a modified tantalum surface by lead dioxide film

&lt;p&gt;The commercial imidacloprid (IMD) insecticide [1-(6-chloro-3-pyridinyl) methyl-4,5-dihydro-N-nitro-1H-imidazole-2-amine] is widely used for the enhancement of crop production, but the intensive use of this insecticide has caused serious environmental problems. This work presents an electrochemical process for the removal of this insecticide using galvanostatic electrolysis at modified tantalum surface by lead dioxide film anode (Ta(PbO2)) anode. The electrolytic process was monitored by chemical oxygen demand (COD). The influence of operating parameters, such as current density, initial concentration of IMD, temperature and initial pH value was investigated. The COD decay follows a pseudo first-order kinetic and the process was under mass transport control. COD removal reach 97% when using an apparent current density of 100 mA cm−2, initial COD of 953 mg L−1 and at 25 °C after 4.5 h electrolysis time.&lt;/p&gt;&#x0D;

Target and non-target impact of systemic insecticides on a polyphagous aphid pest and its parasitoid

Systemic insecticides are used to control agricultural pests globally and their non-target impact at non-lethal doses on beneficial arthropods has been recognized. We assessed the baseline toxicity of imidacloprid, thiamethoxam and sulfoxaflor-based insecticides on the polyphagous aphid pest, Aphis gossypii (Hemiptera: Aphididae), and their non-target effects on its main parasitoid, Aphidius colemani (Hymenoptera: Braconidae), evaluated by residual contact exposure to the median lethal (LC50), the low lethal (LC20) and the sublethal (LC1) concentrations of the three tested insecticides, earlier estimated for the target pest. The results showed that the LC50s for the aphid were 6.4 × 10−3, 5 × 10−3, 2.9 × 10−2 times lower compared to the label concentrations of imidacloprid, thiamethoxam and sulfoxaflor, respectively. LC50 of thiamethoxam caused the highest mortality rate on the parasitoid followed by sulfoxaflor, while imidacloprid had the lowest impact. No significant sublethal effects on reprodution were observed for A. colemani survived to the insecticide exposure. Our findings highlight the importance of case-specific evaluation to optimize pesticide applications in Integrated Pest Management packages taking into account the ecological services provided by biological control agents.

Sub-lethal Effects of Imidacloprid on Nile Tilapia (Oreochromis niloticus)

Imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine (CAS No: 138261–41-3), neonicotinoid insecticide, and agricultural plant protectants were applied as seed and soil treatments. The aim of the present study is to determine the effects of sub-lethal imidacloprid concentrations on the histopathology and oxidative stress parameters with lipid peroxidation (LPO) to standard non-target test organism, tilapia (Oreochromis niloticus). 50 and 100 mgL−1 imidacloprid concentrations were chosen for experimental groups with control group. Fish were stocked in 60 L glass aquaria, maintained in aerated and dechlorinated tap water. The mean weight and length of tilapia were 37.78 ± 2.19 g and 12.98 ± 0.22 cm, respectively. After 24 and 96 h exposure to sub-lethal imidacloprid concentrations, the fish were sacrificed; tissue samples of gill and liver were snap frozen in liquid nitrogen for oxidative stress parameters and LPO assays, fixed (buffered 10% formalin) for histopathology. After exposure to sub-lethal imidacloprid, LPO was induced in both tissues. MDA levels were increased in both tissues, while GSH levels were reduced at the high concentration of imidacloprid in the gill tissues after 96 h and both concentrations in the liver tissues (P 0.05). Gill tissues revealed hyperaemia, epithelial lifting, fusion of secondary lamellae and telangiectasia, whereas hyperaemia, mononuclear cell infiltration vacuolization of hepatocytes and hydropic degeneration were observed in liver tissues. Imidacloprid is very toxic to the non-target species in the aquatic ecosystem even at sub-lethal concentrations.

Ultrasensitive quantitation of imidacloprid in vegetables by colloidal gold and time-resolved fluorescent nanobead traced lateral flow immunoassays

Imidacloprid is a highly effective insecticide, but its potential hazards to the environment and ecosystems have limited its use in many regions. A fast and sensitive analytical method would aid monitoring imidacloprid residues. The monoclonal antibody 4D9, colloidal gold and time-resolved fluorescent nanobeads (CGN and TRFN, respectively) were applied to develop a lateral flow immunoassay (LFIA) for imidacloprid detection in the present work. Both the optimized TRFN-LFIA and CGN-LFIA had a similar limit of detection of approximately 0.02 ng/mL. Use of the portable optical scanner with the TRFN-LFIA or CGN-LFIA could quantitate concentrations of imidacloprid in vegetable as sensitively as the enzyme-linked immunosorbent assay (ELISA). The LFIAs quantitative results of imidacloprid in commercial Chinese leeks were verified by the liquid chromatography-mass spectrometry with a R2 of 0.91. The LFIAs are portable and simple and thus could fully replace the ELISA for onsite quantitation of imidacloprid residues in vegetables.

Toxicity of imidacloprid and chlorpyrifos against German cockroaches Blattella germanica

Background and Aim: As a mechanical vector of some communicable diseases and a self-adaptive species to human environments, the German cockroach can transmit pathogens, such as bacteria, viruses, and fungi, to human beings. This study was conducted to determine the toxicity of imidacloprid and chlorpyrifos against German cockroaches. Materials and Methods: In this experimental study, the last instar German cockroach nymphs were used to test their sensitivity to imidacloprid and chlorpyrifos insecticides by the contact and bait methods. In bioassay (jar test), the nymphs were isolated from the main colony and were exposed to the insecticides for 30 min. The mortality rate was recorded 24 h after the recovery time. In bioassay (bait), 24-96 h after exposure to the poisonous bait, the mortality rate was recorded and regression analysis was run to analyze the data in the SPSS software (IBM, Chicago, USA). Results: The lethal doses (LD) of imidacloprid and chlorpyrifos were 9.5 mg/m2 and 39.78 mg/m2, respectively. The LD50 for imidacloprid and chlorpyrifos were 2.66 and 9.92 mg/m2, respectively. Results revealed that the highest concentration of imidacloprid (45%) could cause the highest mortality rate (95%) 24 h after exposure. There is a significant difference in the mortality of the samples during the follow-up period. Moreover, the chlorpyrifos smeared bait, with a concentration of 16% after 24 h, had the highest mortality rate (95%). Conclusion: The highest mortality rate occurred in the ingestion of imidacloprid smeared bait within the first 48 h after being exposed to the insecticide. Therefore, the results show that imidacloprid can prove significantly effective in controlling cockroaches.

The Inducible CYP4C71 Can Metabolize Imidacloprid in Laodelphax striatellus (Hemiptera: Delphacidae).

Laodelphax striatellus (Fallén) is an important rice pest species which has developed high resistance to imidacloprid. Previous studies have demonstrated that CYP6AY3v2 and CYP353D1v2 were constitutively overexpressed in a imidacloprid resistant strain and can metabolize imidacloprid to mediated metabolic resistance. Further studies still needed to explore whether there are other L. striatellus P450 enzymes that can also metabolize imidacloprid. In this study, the expression level of L. striatellus CYP4C71 was significantly upregulated both in laboratory strains and field strains of L. striatellus after imidacloprid treatment for 4 h. The capability of CYP4C71 to metabolize imidacloprid was investigated. The full-length CYP4C71 was cloned, and its open reading frame was 1,515 bp with an enzyme estimated to be 505 amino acid residues in size. Furthermore, CYP4C71 was heterologously expressed along with L. striatellus cytochrome P450 reductase (CPR) in insect cells. A carbon monoxide difference spectra analysis confirmed the successful expression of CYP4C71. The recombinant CYP4C71 showed high P450 O-demethylation activity with PNP as a substrate. In vitro metabolism studies showed that recombinant CYP4C71 can metabolize imidacloprid to an easily excreted hydroxy-form. The rate of imidacloprid depletion in response to imidacloprid concentration revealed Michaelis Menten kinetics (R2 fitted curve = 0.99) with a relative low affinity: Kcat = 0.032 ± 0.009 pmol depleted imidacloprid/min/pmol P450 and Km=85.19 ± 2.93 μM. A relative big Km (85.19 ± 2.93 μM) indicated relative low imidacloprid's affinity for the CYP4C71 enzyme. In conclusion, CYP4C71 was another P450 enzyme that can metabolize imidacloprid with a relatively low affinity.

Juvenile hormone-mediated reproduction induced by a sublethal concentration of imidacloprid in Cyrtorhinus lividipennis (Hemiptera: Miridae)

Abstract The Hemipteran predator, Cyrtorhinus lividipennis, feeds on the eggs and nymphs of rice planthoppers and leafhoppers. We previously demonstrated that sublethal concentrations of imidacloprid stimulated the reproduction of C. lividipennis. Considering the essential roles of juvenile hormone (JH) in insect reproduction, we speculated that sublethal concentrations of imidacloprid may stimulate the reproduction of C. lividipennis by regulating JH level. To test this, we cloned C. lividipennis JH acid methyl transferase (ClJHAMT) and JH esterase (ClJHE), which are responsible for JH biosynthesis and degradation genes, respectively. We then knocked down ClJHAMT by injecting dsRNA into C. lividipennis nymphs and found that emerging female adults exhibited 88.8% lower expression of the vitellogenin gene (ClVg) and the number of eggs was reduced by 41.5% as compared with controls. Silencing ClJHE increased ClVg mRNA expression by 275.0% but did not affect fecundity. A sublethal concentration of imidacloprid (LC20) increased the JH titer in females by 35.3% and 60.6% at 24 and 48 h post-emergence, respectively. In treatments containing both imidacloprid and dsJHAMT, the silencing of CLJHAMT reduced the number of eggs produced by adult females by 21.4% as compared to the control (imidacloprid + dsGFP). Our results indicated that sublethal concentration of imidacloprid may induce C. lividipennis reproduction by upregulating JH level via JHAMT. The finding could provide valuable information for improved integration of C. lividipennis and insecticides in pest management.

Tolerance of free‐living nematode species to imidacloprid and diuron

AbstractThe neonicotinoid imidacloprid and the herbicide diuron are long‐lived pesticides commonly detected in European rivers. Both have lethal as well as sublethal effects on aquatic invertebrates dwelling in streambeds. Here, we performed lethality tests of imidacloprid and diuron on seven species of widespread, free‐living nematodes and the model organism Caenorhabditis elegans. Our results indicated that nematodes were relatively tolerant to both pesticides, and only two species (Diploscapter coronatus and Plectus opisthocirculus) showed mortality at high nominal concentrations of imidacloprid (119 mg/L) and diuron (33 mg/L). The changes observed in nematode community structure after imidacloprid and diuron exposure may have been related to trade‐offs between sensitivity to toxicants and changes in competitive abilities of the species. While the former can be tested using single‐species tests, we recommend that the latter be tested in further experiments using multispecies communities. Our results suggest that the presence of these pesticides could favor nematodes over other meiofaunal groups found in freshwater sediments.

Traces of Imidacloprid Induce Hormesis as a Stimulatory Conditioned Response of Sweetpotato Whitefly (Hemiptera: Aleyrodidae).

Our purpose is to determine whether extremely low concentrations of imidacloprid (2-8 ppb) typically found in field soil 1-3 yr after a crop is grown using seed with a standard imidacloprid seed-coating could impact the fitness of whiteflies, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). Results of our experiments indicate that imidacloprid-resistant whitefly larvae feeding on cotton seedlings growing in soil with 8.0 ppb imidacloprid are conditioned so that when the same individuals feed on plants treated with imidacloprid as adults their fitness, measured as fecundity, increases 30-70% compared with individuals that were not primed as larvae. This conditioning hormesis stimulates resistant whiteflies more than susceptible whiteflies, which may contribute to the selection of resistant populations.

Food Shortage Amplifies Negative Sublethal Impacts of Low-Level Exposure to the Neonicotinoid Insecticide Imidacloprid on Stream Mayfly Nymphs

Interactions of pesticides with biotic or anthropogenic stressors affecting stream invertebrates are still poorly understood. In a three-factor laboratory experiment, we investigated effects of the neonicotinoid imidacloprid, food availability, and population density on the New Zealand mayfly Deleatidium spp. (Leptophlebiidae). Larval mayflies (10 or 20 individuals) were exposed to environmentally realistic concentrations of imidacloprid (controls, 0.97 and 2.67 μg L−1) for nine days following five days during which individuals were either starved or fed with stream algae. Imidacloprid exposure had severe lethal and sublethal effects on Deleatidium, with effects of the lower concentration occurring later in the experiment. The starvation period had delayed interactive effects, with prior starvation amplifying imidacloprid-induced increases in mayfly impairment (inability to swim or right themselves) and immobility (no signs of movement besides twitching appendages). Few studies have investigated interactions with other stressors that may worsen neonicotinoid impacts on non-target freshwater organisms, and experiments manipulating food availability or density-dependent processes are especially rare. Therefore, we encourage longer-term multiple-stressor experiments that build on our study, including mesocosm experiments involving realistic stream food webs.

Effects of insecticides, fipronil and imidacloprid, on the growth, survival, and behavior of brown shrimp Farfantepenaeus aztecus.

Increased use of pesticide is causing detrimental effects on non-target species worldwide. In this study, we examined the lethal and sub-lethal effects of fipronil and imidacloprid, two commonly used insecticides, on juvenile brown shrimp (Farfantepenaeus aztecus), one of the most commercially and ecologically important species in the United States. The effects of six concentrations of fipronil (0.0, 0.005, 0.01, 0.1, 1.0, and 3.0 μg/L) and six concentrations of imidacloprid (0.0, 0.5, 1.0, 15.0, 34.5, 320.0 μg/L) were tested in a laboratory. We examined five different endpoints: growth, moulting interval, survivorship, behavioral change, and body color change. Growth of shrimp was reduced significantly under higher concentrations of both insecticides. Under fipronil exposure, shrimp in control showed the shortest inter-moult interval (7.57 ± 2.17 day) compared with other treatments; similarly, in the imidacloprid experiment, moulting increased from 8.43 ± 2.52 day in control to 11.95 ± 4.9 day in 0.5 μg/L treatment. Higher concentrations of fipronil (1.0 and 3.0 μg/L) showed a 0.0% survival rate compared with 100% survival in the control and 0.005 μg/L treatment. Under imidacloprid, survivorship decreased from 100% in the control to 33.33% in the 320.0 μg/L treatment. The 96-h LC50 of fipronil was 0.12 μg/L, which makes brown shrimp one of the most sensitive invertebrates to the pesticide. Changes in behavior and body color were observed under both insecticides after different durations of exposures depending on concentrations. We conclude that, at the corresponding EPA benchmark concentrations, fipronil had more lethal effects than imidacloprid, and imidacloprid had more sub-lethal effects than fipronil. Both effects are of serious concern, and we suggest monitoring is necessary in estuaries.

Genome-Wide Analysis of Carboxylesterases (COEs) in the Whitefly, Bemisia tabaci (Gennadius).

The whitefly (Bemisia tabaci), an important invasive pest that causes severe damage to crops worldwide, has developed resistance to a variety of insecticides. Carboxylesterases (COEs) are important multifunctional enzymes involved in the growth, development, and xenobiotic metabolism of insects. However, systematic studies on the COEs of B. tabaci are scarce. Here, 42 putative COEs in different functional categories were identified in the Mediterranean species of B. tabaci (B. tabaci MED) based on a genome database and neighbor-joining phylogeny. The expression patterns of the COEs were affected by the development of B. tabaci. The expression levels of six COEs were positively correlated with the concentration of imidacloprid to which B. tabaci adults were exposed. The mortality of B. tabaci MED adults fed dsBTbe5 (67.5%) and dsBTjhe2 (58.4%) was significantly higher than the adults fed dsEGFP (41.1%) when treated with imidacloprid. Our results provide a basis for functional research on COEs in B. tabaci and provide new insight into the imidacloprid resistance of B. tabaci.

Stress response and toxicity studies on zebrafish exposed to endosulfan and imidacloprid present in water

Abstract Fish and other aquatic biota are hampered by mixtures of pesticides which pollute natural water through agricultural runoff and other sources. Toxicity of combined exposures of endosulfan and imidacloprid on zebrafish in terms of oxidative stress and deoxyribonucleic acid (DNA) damage in liver and histological alterations in gills and muscles was investigated. Zebrafish were exposed to three different sub-lethal concentrations of endosulfan and imidacloprid along with control selected for each treatment for 21 days: control treatment (CT), treatment 1 (T1), treatment 2 (T2) and treatment 3 (T3). T1, T2 and T3 groups were exposed to 0.1, 0.5 and 1 μg/L of endosulfan, respectively, while imidacloprid concentration was maintained at 1 ppm in all three treatments. Oxidative stress was evaluated by measuring levels of catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). Comet assay was applied to measure degree of DNA damage. Dose- and time-dependent decrease in SOD and CAT activity was observed after 21 days of exposure while low concentrations of pesticides induced SOD and CAT activities after early exposure to reduce the oxidative stress. MDA content was found to be increased in T3 having high concentrations of pesticides. Substantial increase in DNA damage was noticed after 21 days' exposure to pesticides. Significant morphological changes were observed in gills relative to muscles.

Determination of Xenobiotic Imidacloprid Content in Surface Waters

Surface water is contaminated by various xenobiotics. Using standardized methods, the content of organochlorine pesticides that are environmentally stable, migrate along food chains and can accumulate in dangerous amounts in living organisms is monitored. In this case, the insecticide imidacloprid is not controlled, however, its ingress into surface and ground waters is not allowed. Seasonal detection of imidacloprid in fish tissues may indicate a violation of regulations for working with imidacloprid preparations. To ensure the necessary preventive regulation and to protect surface water from imidacloprid contamination, a methodology is needed for laboratory monitoring of the general sanitary level of imidacloprid in surface waters. In this work, imidacloprid extracts were obtained based on the liquid-liquid extraction method, the optimal conditions for the quantitative analysis of imidacloprid were determined using high-performance liquid chromatography with a spectrophotometric (diode array detector) detector (HPLC/DAD). The limit of detection of the imidacloprid, which was reached in the work, is 0.15 µg/mL, the limit of quantification is 0.7 µg/mL. Taking into account preliminary concentration (100 times), the lower limit of imidacloprid detection in water is 0.0015 mg/L, the range of determined contents is 0.007–0.028 mg/L. The developed method is simple to perform, allows us to measure the imidacloprid content in one water sample by 90 minutes. The method can be used for monitoring studies of the imidacloprid content in surface water, to collect the water pollution data and forecast its impact.

Acute Toxicity of Imidacloprid on the Developmental Stages of Common Carp Cyprinus carpio

The objective of the present study was to elucidate the toxic effects of imidacloprid on the embryonic and larval stages of common carp (Cyprinus carpio). Each of the 1000 fertilized eggs and larvae were exposed to six different concentrations (0, 10, 30, 100, 300, and 1000 µg/L) of imidacloprid in 30 plastic bowls. Each of the control and treatment was maintained in five replicates. Results showed that hatching rate of fertilized eggs and number of dead embryos and larvae significantly decreased with increasing imidacloprid concentrations. The 24-, 48-, and 72-h LC50 value of imidacloprid for common carp embryos were estimated to be 12,708.8, 611, and 274.9 µg/L, respectively and the 24-, 48-, 72-, and 96-h LC50 of imidacloprid for common carp larvae were estimated to be 93719, 21691, 2352.7, and 1292.6 µg/L, respectively. Furthermore, results showed several malformations of common carp embryos and larvae induced by the toxicity of imidacloprid when exposed to 300 and 1000 µg/L. The results suggest that the minimum concentration of 10 µg/L imidacloprid in the aquatic environment may have adverse effects on the embryonic and larval stages of common carp.

Phagocytic activity of human macrophages and Drosophila hemocytes after exposure to the neonicotinoid imidacloprid

Neonicotinoid insecticides are increasingly used in modern pest control and in conventional agriculture. Their residues are frequently found in our environment and in our food leading to chronic exposure of pollinating insects and humans. Indeed, evidence has become stronger that chronic exposure to neonicotinoids might have a direct impact on the immune response of invertebrates and vertebrates. Therefore, we compared the cellular immune response of human macrophages (THP-1) and Drosophila melanogaster hemocytes (Schneider 2 cells) after exposure to four different concentrations of the neonicotinoid imidacloprid. Cells were immune activated with LPS (lipopolysaccharide) of Escherichia coli to compare the phagocytic activity of immune activated and non-activated cells during pesticide exposure. Drosophila cells were more strongly affected by the insecticide than human macrophages. Even though imidacloprid showed an adverse effect on phagocytosis on both cells while immune activated, it decreased phagocytosis in Drosophila cells at shorter exposure time and without immune activation.