cyhalothrin and phoxim

Although pesticides commonly exist as combinations in real-life situations of the aquatic ecosystem, the impact of the toxicity of their mixtures has remained largely unclear. In this study, we investigated the combined effects of two neurotoxic pesticides, including one organophosphate insecticide phoxim (PHO) and one pyrethroid insecticide lambda-cyhalothrin (LCY), on the embryos of the small yellow croaker (Larimichthys polyactis), and their potential pathways. LCY exhibited higher toxicity relative to PHO, with a 72-h LC

Topics: Animals; Antioxidants; Bile Acids and Salts; Caspase 3; Ecosystem; Insecticides; Nitriles; Organophosphates; Organothiophosphorus Compounds; Perciformes; Pesticides; Pyrethrins; RNA, Messenger; RNA, Ribosomal, 16S; Taurodeoxycholic Acid; Tumor Suppressor Protein p53

Topics: Acaricides; Animals; Italy; Mite Infestations; Mites; Nitriles; Organothiophosphorus Compounds; Poultry; Poultry Diseases; Pyrethrins; Surveys and Questionnaires; Toluidines

Instead of individual ones, pesticides are usually detected in water environment as mixtures of contaminants. Laboratory tests were conducted in order to investigate the effects of individual and joint pesticides (phoxim, atrazine, chlorpyrifos, butachlor and λ-cyhalothrin) on zebrafish (Denio rerio). Results from 96-h semi-static toxicity test indicated that λ-cyhalothrin had the greatest toxicity to the three life stages (embryonic, larval and juvenile stages) of D. rerio with LC

Topics: Acetanilides; Animals; Atrazine; China; Chlorpyrifos; Environmental Monitoring; Larva; Nitriles; Organothiophosphorus Compounds; Pesticides; Pyrethrins; Risk Assessment; Toxicity Tests; Water Pollutants, Chemical; Zebrafish

Although the earthworm Eisenia fetida has been used in many ecotoxicological studies in recent years, most of these studies have only focused on assessing the effects of individual insecticides. In the present study, we aimed to compare the individual and combined toxic effects of imidacloprid and three insecticides (phoxim, chlorpyrifos, and lambda-cyhalothrin) on E. fetida. We showed that imidacloprid had the highest intrinsic toxicity to the worms in filter paper contact test, followed by phoxim and lambda-cyhalothrin, while the least toxicity was found from chlorpyrifos. Moreover, 14-day soil toxicity test revealed that the highest toxicity was still detected for imidacloprid with an LC

Topics: Animals; Chlorpyrifos; Drug Synergism; Ecotoxicology; Imidazoles; Insecticides; Lethal Dose 50; Neonicotinoids; Nitriles; Nitro Compounds; Oligochaeta; Organothiophosphorus Compounds; Pyrethrins; Soil Pollutants; Toxicity Tests

The herbicide butachlor and three insecticides phoxim, chlorpyrifos, and lambda-cyhalotrhin are widely used pesticides with different modes of action. As most previous laboratory bioassays for these pesticides have been conducted solely based on acute tests with a single compound, only limited information is available on the possible combined toxicity of these common chemicals to soil organisms. In this study, we evaluated their mixture toxicity on the terrestrial earthworm, Eisenia fetida, with binary, ternary, and quaternary mixtures. Two different types of bioassays were employed in our work, including a contact filter paper toxicity test and a soil toxicity test. Mixture toxicity effects were assessed using the additive index method. For all of the tested binary mixtures (butachlor-phoxim, butachlor-chlorpyrifos, and butachlor-lambda-cyhalothrin), significant synergistic interactions were observed after 14 days in the soil toxicity assay. However, greater additive toxicity was found after 48 h in the contact toxicity bioassay. Most of the ternary and quaternary mixtures exhibited significant synergistic effects on the worms in both bioassay systems. Our findings would be helpful in assessing the ecological risk of these pesticide mixtures to soil invertebrates. The observed synergistic interactions underline the necessity to review soil quality guidelines, which are likely underestimating the adverse combined effects of these compounds.

Topics: Acetanilides; Animals; Chlorpyrifos; Drug Interactions; Herbicides; Insecticides; Nitriles; Oligochaeta; Organothiophosphorus Compounds; Pesticides; Pyrethrins; Soil; Soil Pollutants; Toxicity Tests; Toxicity Tests, Acute

Myzus persicae (Sulzer) is one of the most important agricultural pests in China, which caused serious losses every year. For resistance monitoring, twelve populations of this pest were collected from tobacco field in Chongqing, China, and their sensitivities to 4 insecticides were tested. Results showed that only WL (RR=6.51) and FJ (RR=6.03) populations have developed minor resistance to imidacloprid, and the others still remained susceptible. One population (NC) has reached a high resistance level to cyhalothrin (RR=41.28), five populations showed medium level (10.36≤RR≤20.45), and the other six remained susceptible (0.39≤RR≤3.53). As regards carbosulfan, three populations have developed medium resistance, four populations showed only minor resistance, and the other five (0.81≤RR≤3.97) were still susceptible. Population SZ developed a medium level (RR=14.83) to phoxim, the other 11 were susceptible (0.29≤RR≤2.41). To analysis the potential resistance mechanism, inhibition effects of synergists and detoxifying enzyme activities were detected. The results indicated that the MFO was the most important detoxifying enzyme conferring imidacloprid resistance, and CarE was most important to cyhalothrin, carbosulfan and phoxim. Our study provided a comprehensive survey of insecticide resistance of M. persicae in Chongqing, and suggested that different counties should take corresponding management to delay the insecticide resistance development and prolong the usefulness of insecticides.

Topics: Animals; Aphids; Biological Assay; Carbamates; China; Imidazoles; Insecticide Resistance; Insecticides; Neonicotinoids; Nitriles; Nitro Compounds; Organothiophosphorus Compounds; Pyrethrins

The combined toxicities of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor), and a heavy metal (cadmium) have been examined using the acute toxicity test on the earthworm. With a concentration of 2.75 mg/kg being lethal for 50% of the organisms, imidacloprid exhibited the highest acute toxicity toward the earthworm Eisenia fetida. Toxicological interactions of these chemicals in ternary mixtures were studied using the combination-index (CI) equation method. Twenty-one ternary mixtures exhibited various interactive effects, in which 11 combinations showed synergistic effects, four led to dual synergistic/additive behaviors, one exhibited an additive effect, and five showed increasing antagonism within the entire range of effects. The CI method was compared with the classical models of concentration addition and independent action, and it was found that the CI method could accurately predict combined toxicity of the chemicals studied. The predicted synergism in the majority of the mixtures, especially at low-effect levels, might have implications in the real terrestrial environment.

Topics: Acetanilides; Animals; Atrazine; Cadmium; Chlorpyrifos; Herbicides; Imidazoles; Insecticides; Ivermectin; Metals, Heavy; Neonicotinoids; Nitriles; Nitro Compounds; Oligochaeta; Organothiophosphorus Compounds; Pyrethrins; Soil Pollutants; Toxicity Tests

The combined toxicity of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor) and a heavy metal (cadmium) has been examined with the earthworm acute toxicity test. Toxicological interactions of these chemicals in four, five, six, seven, and eight-component mixtures were studied using the combination-index (CI) equation method. In four-component and five-component mixtures, the synergistic effects predominated at lower effect levels, while the patterns of interactions found in six, seven, and eight-component mixtures displayed synergism. The λ-CY+IMI+BUT+ATR+CPF+PHO combination displayed the most strongly synergistic interaction, with CI values ranging from 0.09 to 0.15. The nature of the interaction changes with the effect level and the relevance of synergistic effects increase with the complexity of the mixture. The CI method was compared with the classical models of concentration addition (CA) and independent action (IA) and we found that the CI method could accurately predict the combined toxicity. The predicted synergism resulted from co-existence of the pesticides and the heavy metal especially at low effect levels may have important implications in risk assessment for the real terrestrial environment.

Topics: Acetanilides; Animals; Atrazine; Cadmium; Chlorpyrifos; Drug Synergism; Herbicides; Imidazoles; Insecticides; Ivermectin; Metals, Heavy; Neonicotinoids; Nitriles; Nitro Compounds; Oligochaeta; Organothiophosphorus Compounds; Pesticides; Pyrethrins; Risk Assessment; Soil Pollutants

To understand the resistance risks of Frankliniella occidentalis Pergande against phoxim, this paper studied the resistance mechanisms of phoxim-resistant F. occidentalis population against phoxim and the cross-resistance of the population against other insecticides. The phoxim-resistant population had medium level cross-resistance to chlorpyrifos, lambda-cyhalothrin, and methomyl, low level cross-resistance to chlorfenapyr, imidacloprid, emamectin-benzoate, and spinosad, but no cross-resistance to acetamiprid and abamectin. The synergists piperonyl butoxide (PBO), s, s, s-tributyl phosphorotrithioate (DEF), and triphenyl phosphate (TPP) had significant synergism (P < 0.05) on the toxicity of phoxim to the resistant (XK), field (BJ), and susceptible (S) populations, while diethyl maleate (DEM) had no significant synergism to XK and S populations but had significant synergism to BJ population. As compared with S population, the XK and BJ populations had significantly increased activities of mixed-functional oxidases P450 (2.79-fold and 1.48-fold), b, (2.88-fold and 1.88-fold), O-demethylase (2.60-fold and 1.68-fold), and carboxylesterase (2.02-fold and 1.61-fold, respectively), and XK population had a significantly increased acetylcholine esterase activity (3.10-fold). Both XK and BJ population had an increased activity of glutathione S-transferases (1.11-fold and 1.20-fold, respectively), but the increment was not significant. The increased detoxification enzymes activities in F. occidentalis could play an important role in the resistance of the plant against phoxim.

Topics: Acetylcholinesterase; Animals; Chlorpyrifos; Insecticide Resistance; Insecticides; Methomyl; Nitriles; Organothiophosphorus Compounds; Pyrethrins; Thysanoptera

A continuous programme for monitoring resistance of Helicoverpa armigera (Hubner) to commonly used insecticides was undertaken for assessing the impact of Bt cotton planting on the evolution of the pest resistance from 1994 to 2002 in China. The bioassay results showed that the resistance levels per year in field populations of H armigera to lambda-cyhalothrin, phoxim and endosulfan decreased, respectively, to 9-15-fold, 11-14-fold and 6-8-fold in 2001-2002 from 197-262-fold, 52-74-fold and 18-38-fold before the cultivation of Bt cotton in 1997. This significant increase in susceptibility to insecticides is expected to result in a reduction in insecticide application for H armigera control in Bt cotton. It is concluded that Bt cotton is playing an important role in the long-term management of H armigera by increasing the potential for natural and chemical control of the pest.

Topics: Animals; Bacillus thuringiensis Toxins; Bacterial Proteins; Bacterial Toxins; Biological Evolution; China; Endosulfan; Endotoxins; Gossypium; Hemolysin Proteins; Insecticide Resistance; Insecticides; Lethal Dose 50; Moths; Nitriles; Organothiophosphorus Compounds; Plants, Genetically Modified; Pyrethrins; Time Factors

The changes in the susceptibility of the cotton bollworm, Helicoverpa armigera (Hübner) to three insecticides (lambda-cyhalothrin, phoxim and endosulfan) commonly used for control of this pest in China were monitored by bioassays at various generations. The insects were originally collected from Bt cotton fields and selected with Cry1Ac over 44 generations. In comparison with a susceptible strain, the larval resistance of the Bt-selected populations to Cry1Ac toxin increased 106-fold. Simultaneously, the resistance levels to lambda-cyhalothrin, phoxim and endosulfan declined dramatically. The results indicated no positive cross-resistance between Cry1Ac toxin and the insecticides. Evidence of the lack of cross-resistance to three commonly used synthetic insecticides in our laboratory-derived Cry1Ac-resistant population may suggest that growers can confidently use these insecticides if and when resistance to Cry1Ac cotton does occur.

Topics: Animals; Bacillus thuringiensis Toxins; Bacterial Proteins; Bacterial Toxins; Biological Assay; Endosulfan; Endotoxins; Hemolysin Proteins; Insecticide Resistance; Insecticides; Lepidoptera; Nitriles; Organothiophosphorus Compounds; Pyrethrins