bifenthrin and fipronil

The pyrethroid bifenthrin and the phenylpyrazole fipronil are widely employed insecticides, and their extensive use became an environmental issue. Therefore, this study evaluated their biodegradation employing bacterial strains of Bacillus species isolated from leaves of orange trees, aiming at new biocatalysts with high efficiency for use singly and in consortium. Experiments were performed in liquid culture medium at controlled temperature and stirring (32 °C, 130 rpm). After 5 days, residual quantification by HPLC-UV/Vis showed that Bacillus amyloliquefaciens RFD1C presented 93% biodegradation of fipronil (10.0 mg.L

Topics: Bacillus; Bacteria; Citrus sinensis; Pesticides; Pyrethrins

Two commonly used insecticides, bifenthrin and fipronil, can accumulate in the prey of juvenile Chinook salmon, yet the effects of dietary exposure are not understood. Therefore, to better characterize the effect of a dietary exposure route, juvenile Chinook salmon were fed chironomids dosed with a concentration of 9 or 900 ng/g of bifenthrin, fipronil, or their mixture for 25 days at concentrations previously measured in field-collected samples. Chinook were assessed for maximum swimming performance (

Topics: Animals; Dietary Exposure; Glucose; Pyrazoles; Pyrethrins; Salmon; Swimming

Prompt responses to invasive Latrodectus spiders introduced unintentionally are needed worldwide due to their medical and ecological importance. Latrodectus species are chemically controlled using pyrethroid insecticides despite concerns about the ecological impacts of these compounds on biodiversity/ecosystems. Here, the relative sensitivities (acute toxicity: 48-h LC50) of Latrodectus hasseltii Thorell and Latrodectus geometricus C.L. Koch from Japan to the conventional neurotoxic insecticide bifenthrin (pyrethroid) and a new candidate insecticide, fipronil (phenylpyrazole), were examined. Acute residual toxicity tests of these compounds in two nontarget spiders (Parasteatoda tepidariorum C.L. Koch (Araneae: Theridiidae), Badumna insignis L. Koch (Araneae: Desidae)) were conducted for comparison. To test whether bifenthrin and fipronil toxicities differed among the four spiders, corresponding species sensitivity distributions (SSDs) were compared, and hazardous concentrations were determined. Sensitivity (especially in the nontarget species) was two to four orders of magnitude higher for bifenthrin than for fipronil. The SSD patterns of the two insecticides differed significantly, with the spider communities being more sensitive to bifenthrin than to fipronil. The lethal bifenthrin concentration for Latrodectus may reduce spider populations by over 70-90%. If L. hasseltii (established throughout Japan) is targeted for effective population suppression rather than L. geometricus (with a limited distribution range) using the specified insecticide concentration (LC50 value) for fipronil, less than 20% of spider communities will be impacted. Chemical operations aimed at the effective population management and subsequent eradication of invasive Latrodectus spiders while supporting local biodiversity conservation would benefit from considerations of fipronil dosages and target species sensitivities.

Topics: Animals; Ecosystem; Japan; Pyrazoles; Pyrethrins; Spiders

The objective of this study was to determine the effects of cooking and in vitro human digestion on the changes of five insecticides-fipronil, bifenthrin, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), and 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE)-in egg whites and yolks. Each insecticide was applied to egg whites and yolks at a concentration of 1000 μg/g. After cooking the egg whites and yolks, concentrations of bifenthrin, DDD, and DDE decreased (P < 0.05), whereas those of fipronil and DDT were unchanged (P > 0.05) in both egg whites and yolks. Next, an in vitro human digestion model that simulates all the steps of human digestion was employed. Until digestion in the small intestine, the concentrations of fipronil and DDT in the cooked egg whites and yolks were unchanged (P > 0.05), whereas those of bifenthrin, DDD, and DDE decreased (P < 0.05) at each digestion step. In the large intestinal digestion step with Escherichia coli and Lactobacillus sakei as enterobacteria, the concentrations of all the insecticides decreased (P < 0.05) in the cooked egg whites and yolks. Among the insecticides, bifenthrin showed the lowest concentration (P < 0.05). In conclusion, the use of bifenthrin as an insecticide would be comparatively less toxic than other insecticides in terms of environmental pollution and human health, because of its easy degradation.

Topics: Cooking; DDT; Dichlorodiphenyl Dichloroethylene; Dichlorodiphenyldichloroethane; Digestion; Egg White; Egg Yolk; Environmental Pollution; Humans; In Vitro Techniques; Insecticides; Models, Biological; Pyrazoles; Pyrethrins

Pyrethroids are insecticides widely used to control pests and disease vectors in residential areas and agricultural lands. Pyrethroids are emerging pollutants, and their use is a growing concern because of their toxicity potential to aquatic organisms. Todos Santos Bay and the Punta Banda estuary, 2 coastal bodies located to the south of the Southern California Bight, were studied to establish a baseline of the current conditions of pollution by pyrethroids and fipronil. Eight pyrethroids, along with fipronil and its 2 metabolites, were determined in effluents from wastewater-treatment plants (n = 3), surface sediments (n = 32), and 3 locations with mussels (Mytilus californianus, n = 9). Bifenthrin, permethrin, and cypermethrin were the most common pyrethroids found in the study areas and were widespread in sediments, mussels, and wastewater-treated effluents. Fipronil and its metabolites were detected in mussels and wastewater-treated effluents only. Total pyrethroid concentrations in sediments ranged from 0.04 to 1.95 ng/g dry weight in the Punta Banda estuary (n = 13) and from 0.07 to 6.62 ng/g dry weight in Todos Santos Bay (n = 19). Moreover, total pyrethroids in mussels ranged from 1.19 to 6.15 ng/g wet weight. Based on the toxic unit data calculated for pyrethroids and fipronil for Eohaustorius estuarius and Hyalella azteca, little to no impact is expected to the benthic population structure. Environ Toxicol Chem 2017;36:3057-3064. © 2017 SETAC.

Topics: Amphipoda; Animals; Bays; Estuaries; Geologic Sediments; Insecticides; Mexico; Permethrin; Pesticide Residues; Pyrazoles; Pyrethrins; Wastewater; Water Pollutants, Chemical

The aim of this study was to test the bioavailability and degradation in soil of the termiticides bifenthrin and fipronil, which are used to treat subterranean termites (Heterotermes indicola, Wasmann). Soil collected from different areas of Lahore was categorized as sandy clay loam (SCL) or sandy loam (SL). Laboratory bioassays were conducted to determine the bioavailability ratio of bifenthrin and fipronil in each type of soil after different periods of time. LT50 values were determined posttreatment at different time intervals. Regarding soil type, both termiticides were more effective in SL soil, compared with SCL soil posttreatment. There were significant differences in termite mortality in treated compared with untreated control samples (P < 0.005). To test the degradation rate of soil termiticides, both qualitative and quantitative analyses were carried out by HPLC, and the effect of time on termiticide recovery rate determined. Calculated half-life values for bifenthrin (maximum, 1,002 and 1,262 d in SCL soil and SL soil, respectively) indicated that it persisted in both soil types at all concentrations. The maximum calculated half-life values of fipronil were 270 and 555 d in SCL and SL soil, respectively. At lower concentrations and over longer periods of time, fipronil completely degraded in SL soil, while a negligible amount was detected in SCL soil. Termiticide concentration decreased over time, as did the termiticide recovery rate. Overall, bifenthrin was more persistent than fipronil under all treatment conditions tested.

Topics: Animals; Biological Availability; Chromatography, High Pressure Liquid; Half-Life; Insecticides; Isoptera; Pyrazoles; Pyrethrins; Soil

Lambda-cyhalothrin, a sodium channel modulator insecticide, has been used frequently for the control of house flies, Musca domestica L. (Diptera: Muscidae) worldwide, including Pakistan. This experiment was performed to determine the selection and assessment of lambda-cyhalothrin resistance evolution along with four other insecticides. After 26 generations of selection, the lambda-cyhalothrin-selected population developed 445-fold resistance to lambda-cyhalothrin compared to the susceptible population. There was low cross-resistance to bifenthrin and very low cross-resistance to methomyl, imidacloprid, and fipronil in the lambda-cyhalothrin-selected population compared to the field population (G1). Realized heritability (h (2)) of resistance to lambda-cyhalothrin, bifenthrin, methomyl, imidacloprid, and fipronil was 0.07, 0.05, 0.01, 0.08, and 0.08, respectively. The projected rate of resistance development revealed that if 90 % house flies were selected, then a tenfold increase in lethal concentration 50 occurred after 17, 20, 159, 13, and 14 generations for lambda-cyhalothrin (h (2) = 0.07, slope = 2.09), bifenthrin (h (2) = 0.05, slope = 1.73), methomyl (h (2) = 0.01, slope = 2.52), imidacloprid (h (2) = 0.08, slope = 1.89), and fipronil (h (2) = 0.08, slope = 2.03), respectively. The results of our study concluded that the house fly has the potential to develop multiple insecticide resistances following continued selection pressure with lambda-cyhalothrin. This study will be helpful for assisting the development of resistance management strategies.

Topics: Animals; Female; Houseflies; Imidazoles; Insecticide Resistance; Insecticides; Male; Neonicotinoids; Nitriles; Nitro Compounds; Pakistan; Pyrazoles; Pyrethrins

Suisun Marsh, in northern San Francisco Bay, is the largest brackish marsh in California, and provides critical habitat for many fish species. Storm runoff enters the marsh through many creeks that drain agricultural uplands and the urban areas of Fairfield and Suisun City. Five creeks were sampled throughout a major storm event in February 2014, and analyzed for representatives of several major insecticide classes. Concentrations were greatest in creeks with urban influence, though sampling was done outside of the primary season for agricultural pesticide use. Urban creek waters reached maximum concentrations of 9.9 ng/l bifenthrin, 27.4 ng/l fipronil, 11.9 ng/l fipronil sulfone, 1462 ng/l imidacloprid, and 4.0 ng/l chlorpyrifos. Water samples were tested for toxicity to Hyalella azteca and Chironomus dilutus, and while few samples caused mortality, 70% of the urban creek samples caused paralysis of either or both species. Toxic unit analysis indicated that bifenthrin was likely responsible for effects to H. azteca, and fipronil and its sulfone degradate were responsible for effects to C. dilutus. These results demonstrate the potential for co-occurrence of multiple insecticides in urban runoff, each with the potential for toxicity to particular species, and the value of toxicity monitoring using multiple species. In the channels of Suisun Marsh farther downstream, insecticide concentrations and toxicity diminished as creek waters mixed with brackish waters entering from San Francisco Bay. Only fipronil and its degradates remained measurable at 1-10 ng/l. These concentrations are not known to present a risk based on existing data, but toxicity data for estuarine and marine invertebrates, particularly for fipronil's degradates, are extremely limited.

Topics: Amphipoda; Animals; Bays; Chlorpyrifos; Drainage, Sanitary; Ecosystem; Environmental Monitoring; Imidazoles; Insecticides; Neonicotinoids; Nitro Compounds; Pyrazoles; Pyrethrins; San Francisco; Waste Disposal, Fluid; Water Pollutants, Chemical; Wetlands

Tree nurseries and greenhouses within the USDA red imported fire ant (RIFA) quarantine zone are required to incorporate insecticides into their potting media to prevent artificial spread of RIFA. Bifenthrin and fipronil are two common insecticides that are incorporated into potting media. During irrigation and stormwater events, there is potential for insecticides to leach from nursery pots, resulting in the contamination of nearby surface waters. In this study, occurrences of insecticides in simulated nursery runoff were compared with two irrigation strategies and two types of containers in single pot leaching and field runoff simulations. In addition, toxicity of pot leachate to the aquatic invertebrate, Hyallela azteca, was measured, and removal efficiencies of insecticides from bioretention cell media were evaluated. Overhead irrigation resulted in significantly higher concentrations than drip irrigation, and RootMaker pots allowed more leaching as compared to standard slick-wall pots. However, in all tests, the average concentration of bifenthrin during 15 days of leaching in both pot and field simulations was greater than 200 ng/L; more than 100-fold greater than the LC₅₀ for H. azteca. Toxicity studies confirmed this level of toxicity. Higher amounts of compost, 20 and 40%, in bioretention cell media resulted in greater percent reduction of both bifenthrin and fipronil. This study determined that management techniques may be able to limit the amount of insecticide that leaches from pots and runs off to receiving water bodies. Specifically, the selection of appropriate pot types, irrigation strategies, or filtering runoff through bioretention cells may reduce contamination loads. Thus, further best management strategies such as the use of bioretention cells are needed in nursery and greenhouse facilities to prevent surface water runoff from transporting toxic insecticides.

Topics: Agricultural Irrigation; Agriculture; Animals; Crustacea; Insecticides; Pyrazoles; Pyrethrins; Soil; Toxicity Tests, Acute; Water Pollutants, Chemical; Water Pollution

House flies, Musca domestica L., are important pests of dairy operations worldwide, with the ability to adapt wide range of environmental conditions. There are a number of insecticides used for their management, but development of resistance is a serious problem. Insecticide mixtures could enhance the toxicity of insecticides in resistant insect pests, thus resulting as a potential resistance management tool. The toxicity of bifenthrin, cypermethrin, deltamethrin, chlorpyrifos, profenofos, emamectin benzoate and fipronil were assessed separately, and in mixtures against house flies. A field-collected population was significantly resistant to all the insecticides under investigation when compared with a laboratory susceptible strain. Most of the insecticide mixtures like one pyrethroid with other compounds evaluated under two conditions (1∶1-"A" and LC50: LC50-"B") significantly increased the toxicity of pyrethroids in the field population. Under both conditions, the combination indices of pyrethroids with other compounds, in most of the cases, were significantly below 1, suggesting synergism. The enzyme inhibitors, PBO and DEF, when used in combination with insecticides against the resistant population, toxicities of bifenthrin, cypermethrin, deltamethrin and emamectin were significantly increased, suggesting esterase and monooxygenase based resistance mechanism. The toxicities of bifenthrin, cypermethrin and deltamethrin in the resistant population of house flies could be enhanced by the combination with chlorpyrifos, profenofos, emamectin and fipronil. The findings of the present study might have practical significance for resistance management in house flies.

Topics: Animals; Chlorpyrifos; Disaccharides; Drug Combinations; Houseflies; Insecticide Resistance; Insecticides; Ivermectin; Nitriles; Pyrazoles; Pyrethrins

Five formulated insecticides (lambda-cyhalothrin at 10 mg m⁻², bifenthrin at 50 mg m⁻², fipronil at 10 mg m⁻², fenitrothion at 50 mg m⁻², imidacloprid at 5 mg m⁻²) and one active ingredient (DDT at 500 mg m⁻²) were evaluated using a surface contact method against early and late instars and adults of two strains of the tropical bed bug, Cimex hemipterus (F.). Synergism of lambda-cyhalothrin and fipronil using piperonyl butoxide (PBO) was also assessed.. The order of susceptibility of different stages of bed bugs was as follows: early stage-lambda-cyhalothrin > bifenthrin = imidacloprid > fipronil > fenitrothion > DDT; late stage-lambda-cyhalothrin > bifenthrin > fenitrothion > imidacloprid > fipronil > DDT; adult-lambda-cyhalothrin > imidacloprid > bifenthrin > fenitrothion > fipronil > DDT. The late instars exhibited significantly higher LT₅₀ among the life stages. The addition of PBO to fipronil increased the susceptibility of the insects.. Lambda-cyhalothrin, bifenthrin, fenitrothion and fipronil at the recommended application rates were effective against C. hemipterus. Although imidacloprid demonstrated good initial response against C. hemipterus, the insects showed substantial recovery 72 h post-treatment. The late instars (fourth and fifth instars) should be used as the model for toxicological evaluation.

Topics: Animals; Bedbugs; DDT; Drug Synergism; Female; Fenitrothion; Imidazoles; Insecticides; Life Cycle Stages; Male; Neonicotinoids; Nitriles; Nitro Compounds; Pesticide Synergists; Piperonyl Butoxide; Pyrazoles; Pyrethrins; Time Factors; Tropical Climate

Pesticide toxicity may be modified by a number of co-occurring environmental and ecological stressors. Coexposure to predator cues has been shown to potentiate and/or synergize toxicity of pesticides. However, the mechanisms behind these interactions are not well understood. Here we examine the effects of fish predator (bluegill, Lepomis macrochirus) cues on toxicity of five different pesticides to the freshwater cladoceran, Ceriodaphnia dubia. The purpose for examining patterns among pesticides was to test the idea that the mechanism of the interaction could be explained by a general stress response; that is, the interaction patterns would be similar regardless of the pesticide's mechanism of action [MOA]). Acute 96-h concentration-response experiments were conducted for pesticides with and without fish cues. Predator cues influenced the toxicity of pesticides and the interaction patterns varied among pesticides. Fipronil exhibited a synergistic interaction, while predator cues interacted antagonistically for bifenthrin and thiacloprid. Other compounds previously reported to potentiate toxicity (malathion) were found to act additively. The results demonstrate that factors such as pesticide bioavailability, K(OC) , and exposure concentration may be important for predicting the occurrence of these interactions and that patterns were not consistent among pesticides varying in MOA. Predator stress is an important component for structuring communities and ecosystem processes. Fully understanding how this process may interact with organic contaminants may best be achieved by examination at toxicokinetic and toxicodynamic scales.

Topics: Animals; Cues; Daphnia; Drug Interactions; Ecosystem; Fresh Water; Malathion; Neonicotinoids; Perciformes; Pesticides; Pheromones; Predatory Behavior; Pyrazoles; Pyrethrins; Pyridines; Stress, Physiological; Thiazines; Water Pollutants, Chemical

Insecticides are widely used to manage turfgrass pest such as white grubs (Coleoptera: Scarabaeidae). Red imported fire ants, Solenopsis invicta (Buren) are important predators and pests in managed turfgrass. We tested the susceptibility of white grub life stages (adults, egg, and larvae) to predation by S. invicta and determined if insecticides applied for control of S. invicta would result in locally greater white grub populations. Field trials over 2 yr evaluated bifenthrin, fipronil, and hydramethylnon applied to large and small scale turfgrass plots for impacts on fire ant foraging and white grub populations. Coincident with these trials, adults, larvae, and eggs of common scarab species were evaluated for susceptibility to predation by S. invicta under field conditions. Field trials with insecticides failed to show a significant increase in white grub populations resulting from treatment of turfgrass for fire ants. This, in part, may be because of a lack of predation of S. invicta on adult and larval scarabs. Egg predation was greatest at 70% but < 20% of adults and larvae were attacked in a 24 h test. Contrary to other studies, results presented here suggest that fire ants and fire ant control products applied to turfgrass have a minimal impact on white grub populations.

Topics: Alabama; Animals; Ants; Coleoptera; Cynodon; Female; Insecticides; Larva; Male; Ovum; Population Density; Predatory Behavior; Pyrazoles; Pyrethrins; Pyrimidinones; Seasons; Species Specificity

Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Both immobilization and mortality occurred most quickly with bifenthrin, followed by thiamethoxam, chlorfenapyr, and fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30 degrees C, with three ratios of topically treated donor ant corpses to live recipients (5, 10, or 20% donors). Bifenthrin had the greatest horizontal activity of the chemicals tested. For chlorfenapyr, the only treatments having higher mortality than controls were the highest percentage donors at either 10 or 30 degrees C. Horizontal activity of fipronil was temperature dependent only with the highest proportion of donors and was lower than that ofbifenthrin but higher than that of chlorfenapyr or thiamethoxam. Mean mortality due to thiamethoxam was similar to that with chlorfenapyr. Significant mortality occurred in all of the 20 and 30 degrees C thiamethoxam treatments, but none of the 10 degrees C treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control bridge. Mortality data suggest that a reduction in recruitment rather than repellency account for this result.

Topics: Animals; Ants; Insecticides; Neonicotinoids; Nitro Compounds; Oxazines; Pyrazoles; Pyrethrins; Thiamethoxam; Thiazoles; Toxicity Tests

Insecticides are commonly used for ant control around residential homes, but post-treatment runoff may contribute to contamination of surface water in urban watersheds. This study represents the first instance where runoff of insecticides was directly measured after applications around single family residences. During 2007, houses were treated with bifenthrin or fipronil sprays following standard practices. During 2008, pin stream applicators, spray-free zones and restricting sprays to the house foundation were considered as management options.. During 2007, the resulting runoff from the bifenthrin spray in the irrigation water had a mean concentration of 14.9 microg L(-1) at 1 week post-treatment and 2.5 microg L(-1) at 8 weeks, both high enough to be toxic to sensitive aquatic organisms. In comparison, treatments with bifenthrin granules resulted in no detectable concentrations in the runoff water after 8 weeks. The mean concentration for fipronil used as a perimeter spray was 4.2 microg L(-1) at 1 week post-treatment and 0.01 microg L(-1) at 8 weeks, with the first value also suggesting a potential for causing acute aquatic toxicity to sensitive organisms. During 2008, insecticide runoff was reduced by using spray-free zones and pin stream perimeter applications.. It is shown that insecticide runoff from individual home treatments for ants can be measured and used to improve techniques that minimize runoff. The pin stream application and applications limited to the house foundation should be further evaluated for their potential to reduce pesticide runoff from residential homes.

Topics: Animals; Ants; Environmental Pollution; Housing; Insect Control; Insecticides; Pesticide Residues; Pyrazoles; Pyrethrins; Water Pollutants, Chemical

Persistence and efficacy of bifenthrin (25 and 50 g ai ha(-1)), fipronil (50 and 100 g ai ha(-1)) and indoxacarb (70 and 140 g ai ha(-1)) has been studied in okra fruits. The initial deposits varied from 0.259-0.382 microg g(-1) at low and 0.461-0.688 microg g(-1) at high rate of application. The residues persisted upto 10 days with half-life of 1.32-1.58 days for bifenthrin, 0.65-1.12 days for fipronil and 0.58-1.02 days for indoxacarb. Based on ADI, the suggested waiting period was 1 day for bifenthrin and indoxacarb and 3 days for fipronil. All the insecticides were found effective against leafhopper and shoot and fruit borer.

Topics: Abelmoschus; Animals; Half-Life; Insecta; Insecticides; Oxazines; Pyrazoles; Pyrethrins

Degradation and bioavailability of imidacloprid, fipronil, and bifenthrin applied at label rates ([AI], wt:wt in soil) in the loamy soil of Nebraska were determined over a 6-mo duration. Based on the calculated half-lives of the three termiticides, it was concluded that the degradation rate was lowest when a termiticide was applied at the highest label rate. Bioassays of Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) conducted at 8, 31, 65, 90, 135, 160, and 180 d posttreatment showed an inverse relationship between the LT90 values and the variable concentrations. At day 180, exposures to all the termiticide-treated soil samples (concentration x termiticide) resulted in 100% mortality of R. flavipes workers. However, lower LT90 values were observed for termites exposed to soils treated with highest label rates even when the treated soils were aged in the lab for 6 mo. This suggested a higher bioavailability of these three termiticides when applied at higher application rates. Termite mortality was fastest for bifenthrin followed by fipronil and imidacloprid.

Topics: Animals; Biological Availability; Environment; Half-Life; Imidazoles; Insecticides; Isoptera; Neonicotinoids; Nitro Compounds; Pesticide Residues; Pyrazoles; Pyrethrins; Soil

Topics: Adsorption; Animals; Biological Availability; Chromatography, High Pressure Liquid; Imidazoles; Insecticides; Isoptera; Neonicotinoids; Nitro Compounds; Pyrazoles; Pyrethrins; Soil; Soil Microbiology; Soil Pollutants

Horizontal transfer of three contact insecticides, bifenthrin, beta-cyfluthrin, and fipronil, was tested in laboratory colonies. Donor ants were exposed for 1 min to insecticide-treated sand substrates and placed with unexposed ant colonies at two different temperatures. Mortality was monitored to compare the ability of donors to transfer lethal doses of these insecticides to untreated individuals. Treated donor insects, live or dead, were added into colonies to determine the importance of donor behavior on lethal transfer. Fipronil was readily transferable between individuals, resulting in high mortality rates. Bifenthrin and beta-cyfluthrin were less transferable, exhibiting moderate-to-low mortality rates similar to the controls. Greater mortality occurred at 27-29 degrees C than at 21-23 degrees C for bifenthrin, but not the other treatments or controls. Colony mortality did not significantly increase when adding live donors, suggesting that necrophoresis was probably an important donor behavior in addition to grooming and trophallaxis on horizontal transfer.

Topics: Animals; Ants; Insect Control; Insecticides; Nitriles; Pyrazoles; Pyrethrins

Brief exposures of Argentine ants to four different insecticide treatments, bifenthrin, beta-cyfluthrin, bifenthrin + beta-cyfluthrin, and fipronil, were conducted to determine Kaplan-Meier product limit survivorship percentiles (SPs) at 21-23 and 27-29 degrees C. Bifenthrin, beta-cyfluthrin, and bifenthrin + beta-cyfluthrin provided rapid kill at 21-23 degrees C with SP10 values ranging from 11.2 to 33.7 min. Fipronil provided delayed toxicity at 21-23 degrees C with SP10 values ranging from 270 to 960 min. At 27-29 degrees C, all of the SP10 values significantly decreased. Field tests in which Argentine ants were induced to forage across insecticide-treated surfaces were used to determine the effect that speed of action has on foraging and recruitment ability, and whether these insecticides are repellent. The slower-acting fipronil allowed a greater amount of foraging and consequently a greater fraction of the colony to be exposed, whereas fast-acting bifenthrin, beta-cyfluthrin, and bifenthrin + beta-cyfluthrin inhibited recruitment, resulting in fewer ants being exposed and killed. Implications for controlling ants by using perimeter barrier treatments are discussed.

Topics: Animals; Ants; Insect Control; Insect Repellents; Insecticides; Nitriles; Pyrazoles; Pyrethrins; Time Factors