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My thesis is devoted to the resistance of pollen beetle (Meligethes aeneus, son. Brassicogethes aeneus Fabricius, 1775) to pesticides in selected localities in southern Moravia. Collecting adults was performed in the spring of 2013 by tapped into polyethylene bags. Adults are collected from the stands of oilseed rape, mustard and poppy. Tests were performed on the basis of the methodology of Insecticide Resistance Action Committee number 011, 021, 025. In total, we tested the pollen population from 18 locations. For testing, we used the following chemical substances: Biscaya 240 OD, cypermethrin, lambda-cyhalothrin, tau-fluvalinate, etofenprox, chlorpyrifos(ethyl). We evaluated 100% of the registered dose of pesticides after 24 hours. From the results of the individual populations, we found large differences in resistance to chemicals.

Resistence population of pollen beattle on selected locations of Moravia and Silesia were observed during the 2017. Beattles were taked off in the field during spring and their sensitivity to insecticides active substances indoxacarb, chlorpyrifos, thiacloprid, tau-fluvalinate, cypermethrin and lambda-cyhalothrin were tested in laboratory. Tested using methods of IRAC – 11, 21, 25 and 27. Mortality of beattles at various concentrations of active substances was evaluated after 24 hours. Levels of resistance were changed for individual location.

The Asian tiger mosquito, Aedes albopictus (Skuse), is a worldwide nuisance pest that is capable of vectoring several viruses of public health concern. This invasive mosquito has recently expanded its habitable range through its utilization of artificial breeding sites, often due to the activity of humans. These factors, combined with additional expansion due to global changes in climate, have led to invigorated efforts to mitigate the impact of Ae. albopictus. Because it is a diurnal species, standard mosquito control efforts utilizing spray trucks or planes to administer insecticides offer little control, as these methods are directed towards crepuscular species. Barrier spray applications, however, have been shown to achieve a significant reduction in local mosquito pressure while requiring less insecticide application. The design behind barrier sprays is to apply insecticide treatments only around areas of interest, instead of trying to eradicate the local population of mosquitoes. These studies were conducted to evaluate the efficacy of different pyrethroid barrier treatments against Ae. albopictus mosquitoes, and to examine the impact of the most effective treatment on local mosquito populations when applied to suburban residences. Three pyrethroids were examined in these studies: Demand® CS (lambda-cyhalothrin), Talstar® Professional (bifenthrin), and Suspend® Polyzone® (deltamethrin). The following factors affecting pyrethroid barrier treatments showed significant impacts on the knockdown and mortality rates of Ae. albopictus mosquitoes: the plant species, the label rate at which treatments were applied, the active ingredient used in the treatment applications, the time of exposure to the treated foliage, the presence/absence of a blood meal in the mosquito, and the time after treatment. Demand CS treatments showed the highest proportions of knockdown and mortality in adult female Ae. albopictus mosquitoes and did so for the longest amount of time, regardless of the length of the exposure time. Because the Demand CS formulation of lambda-cyhalothrin was shown to be the most effective treatment in the previous studies, it was applied as a barrier treatment to suburban residences in Roanoke, Virginia, in a field trial. Applications of Demand CS as a barrier spray were shown to significantly reduce mosquito catch numbers inside the treated barrier throughout the 8 week study, as compared to the control properties. The findings of these studies indicate that many factors, pertaining to both the insecticides used and to the environment in which they are applied, play a role in influencing the efficacy of a pyrethroid barrier treatment for the control of Aedes mosquitoes. Thus, it is important to gather relevant information before the application of a barrier spray treatment to design the most appropriate program for the situation. / Doctor of Philosophy / Mosquitoes in Virginia are capable of transmitting many different diseases to humans and livestock. Many different treatment options are available to protect humans from these populations of mosquitoes. Some of these options can be performed for a whole community, such as area-wide fogging or treatments from truck-mounted sprayers, while others are applied to properties individually, like mosquito misting systems or barrier sprays. Applying long-lasting insecticides to the edge of an area can help to protect the inside of the area from mosquitoes, and this is called barrier spraying. Barrier sprays, in particular, have become a popular choice for homeowners, and they are successful at limiting human exposure to local mosquito populations. The experiments conducted here looked at three different insecticides used in these treatments and compared them for their ability to inhibit and kill Asian tiger mosquito. Other factors that potentially influenced effectiveness were examined, such as the plant type, the length of time since the treatment was applied, and whether or not the mosquito had taken a blood meal. These experiments examined three commonly used pyrethroid insecticides to determine their efficacy against the local Asian tiger mosquito. Suspend Polyzone lasted a long time but did not produce sufficient mortality, Talstar Professional killed large numbers of mosquitoes, but for a short period, and Demand CS lasted a long time and showed a high mortality rate. These studies showed that the three different insecticides lasted on the plants for different amounts of time, but also that the insecticides needed different amounts of contact time to kill mosquitoes. This information is essential because understanding how a treatment loses effectiveness over time can help with deciding when retreatment is needed. It was also found that the different insecticides were affected by the plants that they were sprayed onto, meaning that certain insecticides did better when sprayed on specific plants. Results from these studies revealed that Asian tiger mosquitoes that had just fed on human blood were more likely to die from insecticide treatments. Thus, even if a mosquito should bite an infected person, barrier spray treatments of their property will lower the chances that the mosquito can spread the disease to other people.

Despite advances in mosquito management, mosquito-borne disease in the United States is still of relevant public health concern and vector control is a top priority in preventing transmission of pathogens. Insecticide barrier sprays have become a common tool for suppression of mosquitoes in single-homeowner backyards. The application of the synthetic pyrethroid, lambda-cyhalothrin to perimeter vegetation with a backpack sprayer has been shown to significantly suppress mosquito levels for around 6 weeks. In an attempt to lengthen the effective duration of treatment, the IGR, pyriproxyfen, was added to a backpack mist blower with lambda-cyhalothrin, as adult mosquitoes exposed to pyriproxyfen have been shown to disseminate it to oviposition sites and to experience lowered fecundity. This treatment was compared to lambda-cyhalothrin alone and to a water control. Mosquito populations were sampled using CO2-baited CDC light traps, CDC gravid traps, human landing rates, and ovitraps. Leaf bioassays were performed. The following summer, the same treatments were applied with a truck-mounted mist blower to tree lines in Central Kentucky, to test the efficacy of an application method that could be used on large properties. Finally, bioassays were performed with water sampled from pyriproxyfen-treated containers, exposed to field conditions to test for residual efficacy.

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La surveillance biologique de l’exposition est reconnue comme approche privilégiée pour évaluer l’exposition aux pesticides pyréthrinoïdes en milieu de travail. Néanmoins, les niveaux d’exposition peuvent être influencés par plusieurs facteurs, dont la coexposition. L’objectif général du projet de thèse était d’évaluer l’impact de la coexposition sur les biomarqueurs d’exposition aux pyréthrinoïdes, par une étude animal in vivo, d’une part, et chez les travailleurs agricoles, d’autre part. En utilisant le pyréthrinoïde lambda-cyhalothrine (LCT) et le fongicide captane comme pesticides sentinelles pour l’étude de cette coexposition, trois objectifs spécifiques ont été établis et ont fait l’objet de trois articles. Dans le premier article, des groupes de rats ont été exposés par gavage à la LCT seule (2,5 ou 12,5 mg/kg p.c.) ou à un mélange binaire de LCT et de captane (2,5/2,5 ou 2,5/12,5 ou 12,5/12,5 mg/kg p.c.). Des collectes de sang et d’excrétas (urine et fèces) ont été effectuées à des intervalles prédéterminés jusqu'à 48 heures après dosage, afin d'établir les profils temporels des principaux métabolites de la LCT (CFMP, 3-PBA et 4-OH3-PBA). Les profils temporels du CFMP et 3-PBA dans le plasma, l'urine et les fèces étaient similaires après exposition à la dose de 2.5 mg/kg pc de LCT seule ou en combinaison avec le captan. Cependant, les niveaux plasmatiques de 3-PBA étaient plus faibles dans le groupe coexposés à la dose élevée. L'excrétion urinaire du 4-OH3PBA était également plus elevée dans le groupe coexposé à cette dose. Dans le deuxième article, les profils temporels individuels des biomarqueurs d'exposition à la LCT chez des travailleurs appliquant des pesticides dans des champs de fraises ont été comparés après un épisode d'application de la LCT seule ou en coexposition avec le captane. Les participants ont fourni toutes leurs urines sur une période de trois jours suivant une application d'une formulation de pesticide contenant de la LCT seule (E1) ou de la LCT mélangée à du captane (E2), et dans certains cas après être retournés dans le champ traité (E3). Les métabolites de pyréthrinoïdes ont été mesurés dans tous les échantillons d'urine, en particulier le CFMP, 3-PBA et 4-OH3BPA. Il n'y avait pas de différences évidentes, attribuables à la coexposition, dans les profils individuels des concentrations en fonction du temps et dans l'excrétion cumulative des métabolites (CFMP, 3-PBA, 4-OH3BPA) après une exposition à la LCT seule ou en combinaison avec le captane. Dans le troisième article, une étude a été menée sur 87 travailleurs agricoles affectés à différentes tâches agricoles (application, désherbage, cueillette). Ces travailleurs ont fourni des échantillons d'urine avant et après l'application de LCT seule ou en combinaison avec du captane, ainsi qu'après des tâches dans les champs traités, avec également un échantillon de contrôle. Les concentrations des métabolites CFMP et le 3-PBA ont été mesurées dans les échantillons. À l'aide d'un questionnaire, les déterminants potentiels d'exposition incluant la tâche effectuée et les facteurs personnels ont également été documentés. Les analyses statistiques ont montré que la coexposition au captane n’induisait pas de changement dans les concentrations urinaires observés de 3-PBA et de CFMP. Seule la tâche professionnelle principale montrait une association avec les niveaux urinaires de ces métabolites. Comparativement aux tâches de désherbage ou de cueillette, la tâche d'application de pesticides était associée à des concentrations urinaires plus élevées de 3-PBA et de CFMP. En résumé, bien qu’un impact de la coexposition LCT-captan a été démontré expérimentalement à de fortes doses, l’étude chez les travailleurs a révélé que la coexposition ne contribuait pas significativement aux variations dans les concentrations des biomarqueurs d'exposition, aux niveaux d'exposition observés chez les travailleurs de la culture de la fraise par rapport aux autres facteurs qui contribuent à cette variabilité. Cette étude a également confirmé les données antérieures suggérant que les applicateurs étaient plus exposés que les travailleurs affectés à des tâches telles que le désherbage et la cueillette. Cette recherche a le potentiel d'améliorer la compréhension de l'impact de la coexposition par rapport à d’autres facteurs sur les niveaux de biomarqueurs d’exposition aux pyréthrinoïdes ; elle contribue ainsi à mieux interpréter les données de biosurveillance. / Biological exposure monitoring is recognized as the preferred approach for assessing exposure to pyrethroid pesticides in the workplace. Nevertheless, exposure levels can be influenced by several factors, including coexposure. The overall aim of the thesis project was to assess the impact of coexposure on biomarkers of exposure to pyrethroids, through an in vivo animal study on the one hand, and in agricultural workers on the other. Using the pyrethroid lambda-cyhalothrin (LCT) and the fungicide captan as sentinel pesticides for the study of this coexposure, three specific objectives were established and were the subject of three published articles. In the first paper, groups of rats were exposed by gavage to LCT alone (2.5 or 12.5 mg/kg bw) or to a binary mixture of LCT and captan (2.5/2.5 or 2.5/12.5 or 12.5/12.5 mg/kg bw). Blood and excreta (urine and faeces) were collected at predetermined intervals up to 48 hours after dosing, to establish the temporal profiles of the main LCT metabolites (CFMP, 3-PBA and 4-OH3-PBA). The temporal profiles of CFMP and 3-PBA in plasma, urine and feces were similar after exposure to 2.5 mg/kg bw of LCT alone or in combination with captan. However, plasma levels of 3-PBA were lower in the high-dose co-exposure group. Urinary excretion of 4-OH3PBA was also higher in the high-dose coexposure group. In the second paper, individual temporal profiles of LCT exposure biomarkers in workers applying pesticides in strawberry fields were compared after an episode of LCT application alone or in coexposure with captan. Participants provided all their urine over a three-day period following application of a pesticide formulation containing LCT alone (E1) or LCT mixed with captan (E2), and in some cases after returning to the treated field (E3). Pyrethroid metabolites were measured in all urine samples, in particular CFMP, 3-PBA and 4-OH3BPA. No differences were observed in individual concentration-time profiles or in the cumulative excretion of metabolites (CFMP, 3-PBA, 4-OH3BPA) after exposure to LCT alone or in combination with captan. In the third article, a study was carried out on 87 farm workers assigned to different agricultural tasks (application, weeding, picking). These workers provided urine samples before and after the application of LCT alone or in combination with captan, as well as after tasks in treated fields, with also a control sample. Concentrations of the metabolites CFMP and 3-PBA were measured in the samples. Using a questionnaire, potential determinants of exposure including the task performed and personal factors were also documented. Statistical analyses showed that coexposure to captan did not lead to any change in the observed urinary concentrations of 3-PBA and CFMP. Only the main occupational task showed an association with urinary levels of these metabolites. Compared with weeding or picking tasks, the pesticide application task was associated with higher urinary concentrations of 3-PBA and CFMP. In summary, although an impact of LCT-captan coexposure has been demonstrated experimentally at high LCT doses, the field study revealed that coexposure did not contribute significantly to variations in exposure biomarker concentrations, at the exposure levels observed in strawberry crop workers compared to other factors contributing to this variability. This study also confirmed previous data suggesting that applicators were more exposed than workers assigned to tasks such as weeding and picking. This research has the potential to improve understanding of the impact of coexposure versus other factors on pyrethroid exposure biomarker levels, and thus contribute to better interpretation of biomonitoring data.

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