Etude de la toxicite chronique de deux insecticides (carbaryl et lindane) a la generation F 1 de Lymnea stagnalis L. (mollusque gasteropode pulmone). I. Croissance des coquilles

In Lymnea stagnalis (F 1 generation) carbaryl weakly disturbs the growth of the shell with 2 ppm, strongly with 4 ppm (lethal concentration for the young snails).The shell growth inhibition by lindane is correlated with the concentration (1 & 2 ppm). The degree of intoxication of parents is very important. The two insecticides play a complex part in the mineralization of the shell. The effects of lindane on growth and mineralization of the shell have a reversible character.     

Etude de la toxicite chronique de deux insecticides (Carbaryl et Lindane) a la generation Fi de Lymnea Stagnalis L. (Mollusque Gasteropode Pulmone). II. Consequences sur le potentiel reproducteur

In Lymnea stagnalis (F1 generation) carbaryl induces a decrease of fecundity for a given age, correlated with the concentration; this decrease is due to a delay in growth. With ppm of lindane a diminution of fecundity is observed which is more prominent with 2 ppm. The number of egg capsules and the number of eggs per capsule are decreased. In F1 intoxicated snails, the degree of the intoxication of their parents seems to play an important part. When the intoxication is stopped, the reversible character is demonstrated.All these chronic intoxication experiments show that lindane is more injurious than carbaryl for the freshwater snails studied.     

Inhibition and recovery of selected target enzyme activities in tissues of penaeid prawn, Metapenaeus monoceros (Fabricius), exposed to different insecticides.

The target enzymes, acetylcholinesterase (for phosphamidon and carbaryl) and Mg2+ ATPase (for DDT and fenvalerate) have been assayed during exposure and reclamation of these insecticides in M. monoceros. Toxicity of these insecticides are in the order: fenvalerate greater than DDT greater than carbaryl greater than phosphamidon. Reclamation studies show that fenvalerate is rapidly degradable while DDT is slowly degradable. It is suggested that pyrethroid, organophosphate and carbamate insecticides may be preferred over organochlorine compounds in farm operations.     

Toxicity assessment of insecticides commonly used in rice pest management to the fry of common carp, Cyprinus carpio, a food fish culturable in rice fields

Toxicity of four insecticides commonly used in rice pest management, chlorpyrifos, dimethoate, carbaryl and carbosulfan, to the fry of common carp was assessed through median lethal concentrations (LC₅₀) and in vivo inhibition of the brain acetylcholinesterase (AChE) enzyme at sublethal concentrations. The 96‐h LC₅₀ values for these four insecticides were determined to be 0.008, 26.11, 7.85 and 0.60 mg L^?1 respectively. Exposure of fish to a series of sublethal concentrations (0.5–5% LC₅₀) of each insecticide for 14 days resulted in concentration‐dependent inhibition in AChE activity in comparison with the controls. AChE activity was greatly inhibited in the fish exposed to sublethal concentrations of chlorpyrifos. Upon transfer to insecticide‐free water, AChE activities in fry exposed to 0.5 and 1% LC₅₀ concentrations of carbaryl and carbosulfan were restored to the control level within 7–21 days whereas the fish exposed to chlorpyrifos or dimethoate did not fully recover from the insecticide‐induced anticholinesterase action. Of the four insecticides tested, chlorpyrifos was the most toxic for the fry of common carp. Although dimethoate was least toxic for the fish under acute exposure, the restoration level of normal AChE activity was slower under chronic exposure in comparison with carbaryl and carbosulfan. Hence, the use of carbamates, especially carbaryl, to control insect pests of rice in rice‐cum‐carp culture systems is recommended when considering survival, restoration of the normal AChE activity and stamina of the cultured fish.     

Investigations into mechanisms responsible for seizures induced by chlorinated hydrocarbon insecticides: the role of brain ammonia and glutamine in convulsions in the rat and cockerel

Abstract— Seizures were produced in adult female rats and in cockerels (Gallus domesticusL.) after the intracarotid administration of four structurally-unrelated chlorinated hydrocarbon insecticides. The temporal relationship of the course of the convulsions to levels in whole brain of ammonia and glutamine was examined. High levels of brain ammonia occurred in rats and cockerels poisoned acutely with lindane, dieldrin, heptachlor and DDT. The intensity of convulsions and other neurological signs coincided with and were directly correlated with the increases in brain ammonia, whereas interictal periods were associated with decreased levels of ammonia. In both species the order of drug toxicity was lindane > dieldrin > heptachlor > DDT. Significantly elevated levels of brain glutamine were induced in the cockerels after administration of all four insecticides. In contrast, increased levels of glutamine in rats were found only in those intoxicated with lindane and dieldrin. Although the ammonia-binding mechanism (conversion of free ammonia into glutamine) was saturated throughout the experiments in both the rats and cockerels, the latter were more resistant to ammonia toxicity by virtue of being able to convert free ammonia into glutamine more efficiently than rats. These data, together with data reported by others, lead to the conclusion that the four structurally-unrelated chlorinated hydrocarbon insecticides probably induced convulsions in both species by a common mechanism, involving interference with the production and/or utilization of ammonia.     

The relative toxicity and persistence of insecticides applied as water-dispersible powders against stored-product beetles

Twelve insecticides, formulated as water-dispersible powders, were applied to strips of filter paper and their toxicities to eight species of stored-product beetles were determined. The insecticides were DDT, methoxychlor, lindane, aldrin, dieldrin, synergized pyrethrins, malathion, fenthion, Chlorthion, diazinon, trichlorphon and carbaryl. The insects were adults of Sitophilus granarius (L.), S. zeamais Mots., Tribolium castaneum (Herbst), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.), Stegobium paniceum (L.), Lasioderma serricorne (F.), and Ptinus tectus Boield. Tables of LD 50 values are presented in terms of deposits of active ingredient between the limits investigated, namely 0.625 and 80 mg./sq.ft., for 2-day and 3-day periods of continuous exposure at 25d? C. and 70% R.H. The data give a broad view of the susceptibility of each insect species to the different insecticides, the effectiveness of each insecticide against the range of insect species, and the speed of action of the insecticides. Trichlorphon had a very low toxicity to all species except O. surinamensis and was omitted from further testing. Deposits of the remaining eleven water-dispersible powders on filter paper were stored and tested at intervals up to 16 months. This yielded information on the persistence of the formulations after application to a chemically inert substrate. Five of the insecticides-malathion, fenthion, Chlorthion, diazinon and carbaryl were then investigated for their persistence on cement, tile, whitewash on tile, wood, and sacking. This test revealed loss of effectiveness of some of the organophosphorus insecticides because of volatility or of alkalinity of the substrate, although some of the results obtained with tiles were difficult to explain. Factors such as surface activity, porosity and real surface area may have played a role, as well as the physical state of the insecticide in the formulation.     

Comparative susceptibility of sweetpotato weevil (Coleoptera: Brentidae) to selected insecticides

The response of sweetpotato weevil, Cylas formicarius (F.) (Coleoptera: Brentidae), to insecticides used for its control was tested in laboratory bioassays. A glass vial bioassay technique was used to determine the susceptibility of two cohorts of sweetpotato weevil to selected insecticides. Vials were treated with methyl parathion, bifenthrin, cyfluthrin, carbaryl, and phosmet. Sweetpotato weevils demonstrated a mortality response to increasing concentrations of all insecticides tested, and our results indicated decreases in susceptibility of the Louisiana cohort of sweetpotato weevil compared with the Texas cohort for all insecticides tested. Methyl parathion was the most toxic chemical tested for both cohorts, followed by the pyrethroids, cyfluthrin and bifenthrin. Phosmet exhibited moderate toxicity compared with other chemicals tested, whereas sweetpotato weevils were least susceptible to carbaryl. Significant differences in lethal concentration (LC)50 and LC90 values for cyfluthrin and bifenthrin, the LC50 values for methyl parathion and phosmet, and the LC90 values for carbaryl were observed between the two cohorts. This study documents baseline toxicological data for five insecticides in two populations of sweetpotato weevil and demonstrates that susceptibility to all insecticides tested is lower for the Louisiana population compared with the Texas population.     

Effect of insecticides on Tiphia vernalis (Hymenoptera: Tiphiidae) oviposition and survival of progeny to cocoon stage when parasitizing Popillia japonica (Coleoptera: Scarabaeidae) larvae

The effect of insecticides on oviposition of Tiphia vernalis Rohwer and subsequent survival of parasitoid progeny to the cocoon stage was determined in the laboratory by using larval Japanese beetle, Popillia japonica Newman, as the host. Insecticides tested were imidacloprid, thiamethoxam, halofenozide, chlorpyrifos, and carbaryl at labeled rates. Female T. vernalis were allowed 2 d to parasitize P. japonica larvae after the parasitoids had received a 4-d exposure to insecticide-treated soil. Another group of female T. vernalis were allowed 2 d to parasitize P. japonica larvae that had been exposed to insecticide-treated soil for 3-4 d. Percentage of parasitism of P. japonica larvae in these trials after exposure of adult parasitoids to carbaryl, chlorpyrifos, halofenozide, or imidacloprid-treated soil (23.3-50.0%) or adult parasitoids to chlorpyrifos, halofenozide, or imidacloprid-treated grubs (33.0-56.7%) was not negatively affected relative to the control treatment (21.7-54.2%). A third group of adult T. vernalis and P. japonica larvae were simultaneously exposed to chlorpyrifos or carbaryl treatments. Percentage parasitism in these trials was lower for T. vernalis adults exposed to the chlorpyrifos and carbaryl (15.0-25.0%) relative to the control (57.5-62.5%) with the exception of one trial with carbaryl (40.0%). However, exposure of the parasitoid and P. japonica to chlorpyrifos 0.5X, carbaryl 0.5X, imidacloprid, halofenozide, or thiamethoxam in several trials resulted in parasitism that was equivalent or greater than (45.0-80.0%) the untreated control (57.5-62.5%). Japanese beetle larval mortality in these trials was greater in the insecticide and parasitoid combination (97.5-100.0%) than with insecticides alone (45.0-100.0%). Percentage of survival of T. vernalis progeny to the cocoon stage was not negatively affected by a 4-d adult parasitoid exposure to carbaryl and chlorpyrifos treated soil (11.7-16.7% versus 18.3% control) or a 2-d exposure to P. japonica-treated larvae (16.7-18.3% versus 28.3% control). However, simultaneous exposure of T. vernalis progeny and P. japonica larvae to chlorpyrifos- and carbaryl-treated soil resulted in no parasitoids surviving to the cocoon stage. Between neonicotinoids, thiamethoxam had more adverse impact on percentage parasitism (52.5%) and survival to the cocoon stage (10.0%) than imidacloprid (80.0 and 32.5%, respectively). Results of this study indicate soil incorporation of imidacloprid and halofenozide had minimal effect on the number of P. japonica larvae parasitized by T. vernalis or survival of T. vernalis progeny to the cocoon stage; therefore, they are more suitable for use with T. vernalis. In contrast, chlorpyrifos, carbaryl, and thiamethoxam lowered the number of T. vernalis progeny surviving to the cocoon stage, and carbaryl and chlorpyrifos reduced the number of P. japonica larvae parasitized. The soil incorporation of insecticides is discussed as one explanation for the minimal effects of some insecticides on T. vernalis.     

Interaction of insecticides with lipid membranes.

The permeability of liposome membranes is increased by organophosphorus and organochlorinated insecticides at concentrations of 10(-5)--10(-4) M. The order of effectiveness is similar to the toxicity of the compounds to mammals, and is the following for permeation of non-electrolytes and for valinomycin-induced permeation of K+: parathion greater than 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) approximately aldrin greater than malathion greater than lindane. The degree of effectiveness for X-537A-induced permeation of Ca2+ was the following: aldrin greater than or equal to DDT greater than parathion greater than malathion greater than lindane. The organophosphorus compound, ethyl azinphos (10(-4) M), dramatically increases the permeability of liposome membranes to all the tested substances, probably as a consequence of surfactant effects. Some organochlorinated insecticides appear to react with cation ionophores and modulate their motion across lipid membranes. It is suggested that the insecticides may exert some of their toxic actions by modifying certain mechanisms in the cell membrane.     

Monitoring of chemical fertilizers on toxicity of two carbamate insecticides to the cyanobacterium Anabaena PCC 7120

The effects of individual chemical fertilizers (urea, superphosphate and potash) on the toxicity of two carbamate insecticides (carbaryl and carbofuran) to the nitrogen-fixing cyanobacterium Anabaena PCC 7120, were studied in vitro at partial lethal levels of each insecticide. Urea at 10 and 50 ppm levels reduced the toxicity due to carbaryl at 50 ppm partial lethal dose and due to carbofuran at 100 and 250 ppm partial lethal doses. Urea at 100 ppm enchanced the toxicity of both insecticides. Superphosphate at 10 ppm reduced the toxicity of carbaryl at 50 ppm and carbofuran at 100 and 250 ppm, but it enhanced the toxicity due to both insecticides at 50 ppm superphosphate. The toxicity due to carbaryl at 40 and 60 ppm were reduced by 100 and 200 ppm potash, but higher potash levels caused enhancement of toxicity. Carbofuran toxicity at 100 ppm was reduced but at 250 ppm the toxicity was enhanced with 100 ppm potash. Urea, superphosphate and potash caused no significant change in number of vegetative cells between the successive heterocysts at 10 and 50 ppm of urea and superphosphate, respectively, and 100 ppm of potash.     

Effect of dieldrin and lindane on the growth and nodulation ofVicia faba

The chlorinated hydrocarbon insecticides, dieldrin and lindane, were used at the normal and 20-fold rate. The plants were grown in pots containing clay soil. The results showed that whereas low and high concentrations of dieldrin as well as low concentration of lindane had no effect on the morphological characters of the shoot and root systems, high concentration of lindane had a harmful effect. Nodulation was slightly affected by low and high concentrations of dieldrin as well as low concentration of lindane. High concentration of lindane had a deleterious effect on nodulation.     

Sublethal effects of neuroactive compounds on pheromone response thresholds in male oriental fruit moths

The pheromone-mediated flight behavior of male Oriental fruit moths in a sustained-flight tunnel was observed after males were treated topically with sublethal concentrations of permethrin, carbaryl, chlordimeform, dieldrin, octopamine, serotonin, yohimbine, and cyproheptadine. With the exception of serotonin all compounds were found to disrupt one or more specific elements of the male precopulatory flight sequence. Among the insecticides, dieldrin was least active, whereas permethrin, carbaryl, and chlordimeform induced unique effects at specific phases of the sequence. Octopamine induced a hypersensitivity to the olfactory signal and mimicked one of the effects observed with chlordimeform. Yohimbine and cyproheptadine significantly decreased moth activation to the chemical signal but did not alter flight performance in responding moths. Yohimbine and cyproheptadine also reversed the effects induced by octopamine. The results of our study show that the complex precopulatory sequence of behaviors exhibited by males is very sensitive to sublethal concentrations of a range of neuroactive compounds.     

Toxicity of certain insecticides toSturmiopsis inferens,a larval parasite of sugarcane moth borers

Susceptibility of adults and puparia ofSturmiopsis inferens Tns. [Tachinidae, Diptera] to 9 commonly recommended insecticide sprays against sugarcane pests was determined. The chemicals tested as emulsifiable concentrates include lindane 0.1%, endosulfan 0.1%, monocrotophos 0.05%, quinalphos 0.05%, malathion 0.1%, dimethoate 0.1%, cypermethrin 0.01%, fenvalerate 0.01% and decamethrin 0.0014%. Lindane, malathion, dimethoate monocrotophos and quinalphos were highly toxic, while decamethrin had little harmful effect to the adults when exposed for 6 h to filter paper impregnated or sugarcane shoot bits sprayed with the chemicals. However, the insecticides had no harmful effect on the puparia and adult emergence was normal from the puparia sprayed with insecticides. In another study, susceptibility of adults to soil application of lindane EC, carbofuran G, chlorpyriphos G, Sevidol G and whorl application of lindane G, chlorpyriphos G and Sevidol G was tested in pot culture. Except for soil application of lindane EC, all other chemicals had no harmful effect to the adults in pot culture experiment. In a field trial, commonly recommended insecticides against shoot borer,Chilo infuscatellus Snell.viz., soil application of granules of lindane, carbofuran, chlorpyriphos and Sevidol and folia spray of endosulfan did not affect the parasite activity. Institute Publication No 1030.     

Comparative susceptibility of western corn rootworm (Coleoptera: Chrysomelidae) adults to selected insecticides in Kansas

Susceptibility of adult populations of the western corn rootworm, Diabrotica virgifera virgifera LeConte, to several insecticides was evaluated in seven Kansas counties, including Dickinson, Ford, Finney, Pottawatomie, Republic, Riley, and Stevens, between 1996 and 2002. All populations surveyed were highly susceptible to methyl parathion with the largest difference in susceptibility of only three-fold based on 16 complete bioassays for the populations from six counties over a 5-yr period. Noticeable decreases in carbaryl susceptibility were found in populations collected from Republic County between 1997 and 2001 when the cucurbitacin-carbaryl-based bait SLAM was widely used as an areawide management approach for adult corn rootworm control. However, the lowered carbaryl susceptibility returned to previous levels 1 yr after the use of SLAM was halted in the managed (treated) cornfields. This change implies possible dispersal of insects into the relatively small managed area from surrounding untreated cornfields and / or some fitness cost associated with carbaryl resistance within the population. Relative susceptibility of western corn rootworm adults also was evaluated for seven commonly used insecticides, including bifenthrin, carbaryl, chlorpyrifos, cypermethrin, fipronil, malathion, and methyl parathion. They were tested with corn rootworm adults collected from a single cornfield. Methyl parathion and bifenthrin were highly toxic to corn rootworm adults, and cypermethrin, chlorpyrifos, carbaryl, and malathion were only slightly less toxic. Although fipronil was highly toxic to adult rootworms, its activity was much slower than that of other insecticides. Thus, bifenthrin and methyl parathion were among the most effective in killing corn rootworm adults.     

Muscular and brain cholinesterase sensitivities to azinphos methyl and carbaryl in the juvenile rainbow trout Oncorhynchus mykiss

The organophosphate azinphos methyl (AzMe) and the carbamate carbaryl are the insecticides mostly used in the irrigated valley of Río Negro and Neuquén, Patagonia, Argentina. Juvenile rainbow trout were exposed to AzMe and carbaryl and the sensitivity of skeletal muscular cholinesterase (ChE) and the time course of inhibition and recovery were evaluated. EC50 values demonstrated that AzMe was a stronger in vivo inhibitor of muscular ChE (1.05+/-0.23 microg/L) than carbaryl (270+/-62.23 microg/L). Muscular ChE was significantly less sensitive to both insecticides than brain ChE. EC50 values obtained for muscular ChE were closer than those for brain ChE to the respective pesticide lethal concentrations, pointing out the relevance of the muscular enzyme in determining acute toxicity. The recovery process of ChE activity after carbaryl exposure (500 microg/L) was fast, whereas no significant recovery was observed with AzMe (1 microg/L) after 21 days in uncontaminated media. Brain and muscular ChE were inhibited and showed a significant but not complete recovery after three consecutive 48-h exposures to AzMe (1 microg/L) followed by a recovery period of 7 days. This scheme mimics the periodical application of the insecticides in the region and suggests a certain probability of a sustained ChE inhibition under field conditions, affecting fish development and survival.     

Alteration of the binding constants of malathion and carbaryl to cytochrome P-450 due to hydrolysis by rat hepatic microsomal esterases

During studies to determine spectral binding properties of malathion and carbaryl to rat liver microsomal cytochrome P-450, it was observed that final concentrations of 5 μM malathion and 10 μM carbaryl produced unstable binding spectra. Evidence is presented which demonstrates that a major reason for the unstable binding spectra of these insecticides is rapid degradation by hepatic microsomal esterases. In this respect, carbaryl and malathion, and possibly other compounds that contain ester linkages, appear to be unique, since most compounds are not metabolized under the conditions in which binding spectra are determined, i.e. in the absence of an NADPH generating system.     

Toxicity of two carbamate insecticides to the cyanobacterium Anabaena PCC 7120 and computations of partial lethal concentrations by the probit method

Toxicity studies of two commercial carbamate insecticides, carbaryl and carbofuran with the nitrogen-fixing filamentous cyanobacterium Anabaena PCC 7120, are described. Under nitrogen-fixing conditions and with calcium nitrate supplementation, 100 and 120 ppm carbaryl were the respective lethal concentrations (LC100), while 20 to 80 ppm (nitrogen-fixing conditions) and 20 to 100 ppm (with nitrate supplementation) were the partial lethal doses (相似文献   

Rainfastness and residual activity of insecticides to control Japanese beetle (Coleoptera: scarabaeidae) in Grapes

Field-based bioassays and residue profile analysis were used to determine the relative toxicity, rainfastness, and field degradation over time of five insecticides from five insecticide classes on adult Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), in grapes, Vitis labrusca L. Bioassays assessed Japanese beetle condition as alive, knockdown, or immobile when exposed for 24 h or 7-d field-aged residues of phosmet, carbaryl, bifenthrin, thiamethoxam, or indoxacarb after 0, 12.7, or 25.4 mm of rain had been simulated. We found that the two most toxic insecticides to Japanese beetle were phosmet and carbaryl, followed by bifenthrin, thiamethoxam, and then indoxacarb. The efficacy of phosmet decreased because of rainfall, but not because of field aging. The efficacy of carbaryl decreased because of rainfall and field aging. The efficacies of bifenthrin and thiamethoxam were not affected by rainfall but decreased because of field aging. The efficacy of indoxacarb was not affected by rainfall or field aging. This study will help vineyard managers make informed decisions on when reapplications of insecticides are needed with the aim of improving integrated pest management programs.     

Degradation of lindane and endosulfan by fungi, fungal and bacterial laccases

The ability of two white-rot fungi (Trametes versicolor and Pleurotus ostreatus) and one brown-rot fungus (Gloeophyllum trabeum) to degrade two organochlorine insecticides, lindane and endosulfan, in liquid cultures was studied and dead fungal biomass was examined for adsorption of both insecticides from liquid medium. Lindane and endosulfan were also treated with fungal laccase and bacterial protein CotA, which has laccase activities. The amount of degraded lindane and endosulfan increased with their exposure period in the liquid cultures of both examined white-rot fungi. Endosulfan was transformed to endosulfan sulphate by T. versicolor and P. ostreatus. A small amount of endosulfan ether was also detected and its origin was examined. Degradation of lindane and endosulfan by a brown rot G. trabeum did not occur. Mycelial biomasses of all examined fungi have been found to adsorb lindane and endosulfan and adsorption onto fungal biomass should therefore be considered as a possible mechanism of pollutant removal when fungal degradation potentials are studied. Bacterial protein CotA performed more efficient degradation of lindane and endosulfan than fungal laccase and has shown potential for bioremediation of organic pollutants.     

亚致死剂量马拉硫磷和西维因对飞蝗P450基因表达研究

采用实时定量PCR技术检测飞蝗Locusta migratoria细胞色素P450基因CYP4G62、CYP6EL1和CYP9AQ1经马拉硫磷和西维因不同亚致死剂量和不同时间处理后mRNA的表达水平。结果表明,经马拉硫磷不同亚致死剂量LD10、LD30和LD50处理后,飞蝗CYP4G62和CYP6EL1均在高剂量LD50被显著诱导,分别为对照的3.03和2.0倍,而在低剂量LD10无显著性差异。CYP9AQ1在3个亚致死剂量下表达量均显著提高,且增量随处理浓度增加而降低。经西维因3个亚致死剂量处理后,除在LD30这一浓度下引起CYP4G62表达提高外,其它的P450基因均无显著性差异。选择2种农药的LD15对飞蝗进行点滴处理,分别检测6、12、24和48 h基因的相对表达。经马拉硫磷LD15处理后,除CYP6EL1在12 h和CYP9AQ1在24 h表达量显著降低外,其它各时间点基因表达均无显著差异。经西维因处理不同时间后,3个P450基因的相对表达量均无显著性差异。综合上述结果说明马拉硫磷对3个细胞色素P450基因有一定的诱导作用,而西维因对其无诱导作用。