Pesticide Combinations Research Articles

Differentiating metabolomic responses of amphibians to multiple stressors

One of the biggest challenges in ecological risk assessment is determining the impact of multiple stressors on individual organisms and populations in real world scenarios. Frequently, data derived from laboratory studies of single stressors are used to estimate risk parameters and do not adequately address scenarios where other stressors exist. Emerging ‘omic technologies, notably metabolomics, provide an opportunity to address the uncertainties surrounding ecological risk assessment of multiple stressors. The objective of this study was to use metabolomic profiling to investigate the effect of multiple stressors on amphibian metamorphs. We exposed post-metamorphosis (180 days) southern leopard frogs (Lithobates sphenocephala) to the insecticide carbaryl (480 μg/L), predation stress, and a combined pesticide and predation stress treatment. Corticosterone analysis revealed mild support for an induction in response to predation stress alone but strongly suggests that carbaryl exposure, alone or in combination with predation cues, can significantly elevate this known biomarker in amphibians. Metabolomics analysis accurately classed, based on relative nearness, carbaryl and predation induced changes in the hepatic metabolome and biochemical fluxes appear to be associated with a similar biological response. Support vector machine analysis with recursive feature elimination of the acquired metabolomic spectra demonstrated 85–96% classification accuracy among control and all treatment groups when using the top 75 ranked retention time bins. Biochemical fluxes observed in the groups exposed to carbaryl, predation, and the combined treatment include amino acids, sugar derivatives, and purine nucleotides. Ultimately, this methodology could be used to interpret short-term toxicity assays and the presence of environmental stressors to overall metabolomic effects in non-target organisms.

Pengaruh kombinasi kitosan soluble liquid dan pestisida sintetik terhadap pertumbuhan dan hasil panen cabai keriting di Nganjuk

Abstract Chitosan has the potential as a biostimulant also as an antagonistic agent due to its antimicrobial activity. These dual benefits were the superiority of chitosan and has the potential to be developed further. The objective of this study was to analyze the effect of soluble liquid (SL) chitosan on plant growth and the yield of curly chili. The study was conducted from April-August 2019 in Prambon Subdistrict, Nganjuk District, East Java. The total experimental plot was 2.000 m2 rows with 45 x 70 cm plant spacing. The variety of curly chili used was Kribo with three treatments examined i.e., the application of single chitosan SL (P1), the combination of chitosan SL and synthetic pesticide (P2), and the conventional application of synthetic pesticide that considered as control (K). Each treatment was replicated four times. The application of chitosan SL was conducted at 21, 42, and 63 days after planting (DAP) by foliar spray. The result showed that the application of chitosan SL increased the canopy width by 16,34% and plant height by 11,53% against control at 99 DAP. The number of fruits per plant also increased by 123% on P1 and 20% on P2 treatment. The fruit weight was also increased by 42,6% on P2 and 18% on P1 treatment. The conversion result showed that single chitosan SL application was able to increase the production of curly chili per hectare up to 163%, while the combination of chitosan SL and synthetic pesticide resulted up to 71% increase in curly chili production compared to control. Chitosan has the potential as a biostimulant also as an antagonistic agent due to its antimicrobial activity. These dual benefits were the superiority of chitosan and potentially to be developed further. The objective of this study was to analyze the effect of soluble liquid (SL) chitosan on the growth and yield of curly chili. The variety of curly chili used was Kribo with three treatments examined i.e. the application of single chitosan SL (P1), the combination of chitosan SL and synthetic pesticide (P2), and the conventional application of synthetic pesticide that considered as control (K). Each treatment was replicated four times. The application of chitosan SL was conducted at 21, 42, and 63 days after planting (DAP), while the application of synthetic pesticide was conducted depending on the field conditions. The plant parameters observed were canopy width, plant height, leaf color, and number, and weight of fruits. The observation results were analyzed using table of variance. The results showed that the application of chitosan SL increased the canopy width by 16.3% and plant height by 11.5% compared to control at 99 DAP. The number of fruits per plant also increased by 123% on P1 and 20% on P2 treatment. The fruit weight was also increased by 42.6% on P2 and 18% on P1 treatment. The conversion result showed that single chitosan SL application was able to increase the yield of curly chili per hectare up to 163%, while the combination of chitosan SL and synthetic pesticide resulted in 71% increase in curly chili yield compared to the control.[Keywords: antagonistic agent, biostimulant, chili var. Kribo, production, soluble liquid] Abstrakmikroba. Kedua manfaat ini yang menjadi keunggulan kitosan dan berpotensi untuk dikembangkan lebih lanjut. Penelitian ini bertujuan untuk menganalisis pengaruh aplikasi kitosan soluble liquid (SL) terhadap pertumbuhan dan hasil panen tanaman cabai keriting. Varietas cabai keriting yang digunakan adalah Kribo dengan tiga perlakuan yang diuji, yakni aplikasi kitosan SL tunggal (P1), kombinasi kitosan SL dengan pestisida sintetik (P2) dan aplikasi pestisida sintetik secara konvensional sebagai kontrol (K). Masing-masing perlakuan diulang empat kali. Aplikasi kitosan SL dilakukan pada umur tanaman 21, 42 dan 63 hari setelah tanam (HST), sedangkan aplikasi pestisida sintetik dilakukan berdasarkan kondisi di lapangan. Parameter tanaman yang diamati antara lain lebar kanopi, tinggi tanaman, warna daun, serta jumlah, dan berat buah. Hasil pengamatan dianalisis menggunakan tabel sidik ragam. Hasil penelitian menunjukkan bahwa aplikasi kitosan SL mampu meningkatkan lebar kanopi dan tinggi tanaman sebesar 16,3% dan 11,5% terhadap kontrol pada umur tanaman 99 HST. Jumlah buah per tanaman juga mengalami kenaikan sebesar 123% pada perlakuan P1 dan 20% pada perlakuan P2. Berat per buah mengalami kenaikan sebesar 42,6% pada perlakuan P2 dan 18% pada perlakuan P1. Hasil konversi menunjukkan bahwa aplikasi kitosan SL tunggal mampu meningkatkan produksi cabai keriting per hektar hingga 163%, sedangkan aplikasi kombinasi kitosan SL dan pestisida sintetik meningkatkan produksi sebesar 71% dibandingkan kontrol.[Kata kunci: agen antagonis, biostimulan, cabai var. Kribo, produksi, soluble liquid]

Multiple-stressor exposure of aquatic food webs: Nitrate and warming modulate the effect of pesticides

Shallow lakes provide essential ecological and environmental services but are exposed to multiple stressors, including agricultural runoff (ARO) and climate warming, which may act on different target receptors disrupting their normal functioning. We performed a microcosm experiment to determine the individual and combined effects of three stressors—pesticides, nitrate and climate warming—on two trophic levels representative of communities found in shallow lakes. We used three submerged macrophyte species (Myriophyllum spicatum, Potamogeton perfoliatus, Elodea nuttallii), eight benthic or pelagic microalgal species and three primary consumer species (Daphnia magna, Lymnaea stagnalis, Dreissena polymorpha) with different feeding preferences for benthic and pelagic primary producers. Eight different treatments consisted of a control, only nitrate, a pesticide cocktail, and a combination of nitrate and pesticides representing ARO, each replicated at ambient temperature and +3.5°C, mimicking climate warming. Pesticides negatively affected all functional groups except phytoplankton, which increased. Warming and nitrate modified these effects. Strong but opposite pesticide and warming effects on Myriophyllum drove the response of the total macrophyte biomass. Nitrate significantly suppressed Myriophyllum final biomass, but not overall macrophyte and microalgal biomass. Nitrate and pesticides in combination caused a macrophyte decline, and the system tipped towards phytoplankton dominance. Strong synergistic or even reversed stressor interaction effects were observed for macrophytes or periphyton. We emphasize the need for more complex community- and ecosystem-level studies incorporating multiple stressor scenarios to define safe operating spaces.

Acute Toxicity of Fungicide-Insecticide-Adjuvant Combinations Applied to Almonds During Bloom on Adult Honey Bees.

Beekeepers report significant honey bee deaths during and after almond bloom. These losses pose a major problem for the California almond industry because of its dependence on honey bees as pollinators. The present study aimed to determine if combinations of pesticides applied during almond bloom during daylight hours were a possible explanation for these losses. In this study we aimed to mimic the spray application route of exposure to pesticides using a Potter Spray Tower to treat adult honey bees with commonly encountered pesticides and pesticide combinations at multiples of the maximum recommended field application rates. Tested insecticides included Altacor® and Intrepid®, and tested fungicides included Tilt®, Pristine®, Luna Sensation®, and Vangard®. Synergistic toxicity was observed when the fungicide Tilt (active ingredient propiconazole) was applied with the insecticide Altacor (chlorantraniliprole), though neither caused significant mortality when applied independently. The study also looked at the effect of adding a spray adjuvant, Dyne‐Amic®, to pesticide mixtures. Dyne‐Amic was toxic to honey bees at concentrations above the maximum recommended field application rate, and toxicity was increased when combined with the fungicide Pristine (pyraclostrobin and boscalid). Addition of Dyne‐Amic also increased toxicity of the Tilt and Altacor combination. These results suggest that application of Altacor and Tilt in combination with an adjuvant at the recommended field application rates could cause mortality in adult honey bees. These findings highlight a potential explanation for honey bee losses around almond bloom, emphasize that the safety of spray adjuvants to bees should not be assumed, and provide support for recommendations to protect bees from pesticides through application at night when bees are not foraging. Environ Toxicol Chem 2022;41:1042–1053. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Detecting the combined toxicity of 18 binary and 24 ternary pesticide combinations to carboxylesterase based on fluorescence probe technology

A rapid test method for the determination of pesticide toxicity was established by using carboxylesterase (CES) and fluorescence probe ACE-NH based on the principle of enzyme inhibition, and this method was applied to detect the combined toxicity of 18 binary and 24 ternary pesticide combinations commonly used for fruits and vegetables to CES. The results show that chlorpyrifos + carbendazim, carbofuran + carbendazim, imidacloprid + carbendazim, imidacloprid + dimethomorph, dimethoate + dimethomorph, prochloraz + carbendazim and imidacloprid + acetamiprid + carbendazim had synergistic effects under three concentration gradients, it indicated that most binary combinations containing carbendazim or imidacloprid had synergistic effects. Based on structure-activity relationship between pesticides and CES, pesticides with phosphate ester bonds had great toxicity to CES, or though they have no toxicity to CES alone, they showed a strong synergistic effect when mixed with other pesticides. Pesticides with amide or ester bond had medium toxicity and little synergistic effect. Pesticides with urea, carbamate or nitrite nitrogen group had little or no toxicity, while there was a strong synergistic effect after mixing with other pesticides. The test method and results in this study can provide scientific basis for risk assessment of cumulative exposure to mixed pesticide residues.

Quantitative and qualitative analysis of bottle gourd (Lagenaria siceraria): Impact of organic liquid fertilizer

At present, organic farming practices are getting more attention around the world owing to their sense of nutrition. Interestingly, nutrition refers to the taking of nutrients from food and utilizing for growth and molecular metabolism. Currently, organic farming involves the judicious combination of green manures, animal manures, bio-fertilizer, bio-botanical pesticides and crop rotations as well as crop residues. Among them, Panchakavya, Bijamrutha and Jivamrutha have come in to the line of natural agriculture. Therefore, the present study explored the bottle gourd (Lagenaria siceraria) growth along with these products for various treatments. In this bottle gourd, three different components were used for Panchagavya, Beejamrutha and Jeevamrutha at ten different concentrations. Along with this, one control was maintained for this plant. Various morphological parameters were used to identify plant growth such as plant height, root length, shoot length, and flowers count. Finally, harvested vegetables are used for quality analysis such as ascorbic acid, vitamin-C, phenolic compounds, antioxidants and nutrient analysis. From this study, plants using organic fertilizers shows significantly increased nutrient content and plant growth compared to control. The combination of Panchakavya + Bijamrutham + Jeevamrutha achieves excellent growth with eco-friendly and low cost liquid fertilizer nutrient enrichment.

Гігієнічне регламентування безпечного застосування комбінованих пестицидів в системі захисту яблуневих насаджень від шкідників, хвороб і бур’янів

Background: The quality and safety of agricultural product, grown with the application of chemical plant protection products, is an urgent problem of preventive medicine. The occurrence of multiple pesticide residues in the foodstuffs is of concern to the general public and is engaging scientists in the search for approaches to the assessment and control of multi-residues. Objective: We analyzed a range of the active substances of combined pesticides used in Ukraine in modern apple orchard protection systems, characterized a hazard and assessed the combined exposure to several pesticides at their joint ingress with apples into the human body. Materials and methods: In the work, we applied the methods of analytical research of the range of active substances of pesticides, registered and used in Ukraine in modern systems of apple orchard protection, by functional purpose (herbicides, insecticides, acaricides, fungicides); used the normative documents of national legislation on hygienic regulation of pesticides and methodological approaches to the assessment of the combined effects of pesticide mixtures in the foodstuffs. Results: According to the results of the analysis of the residues of active substances of pesticides in apples, the conclusion about the low level of short-term (acute) risk for health consumers has been made. However, it is impossible to ignore a presence of many pesticides with a similar mechanism of biological action in food, and hence, a possibility of their additive or synergistic effect on health. Conclusions: Further research should be aimed at assessing the exposure and identifying the health hazards of the consumers from the combined effect of pesticides, applied for vegetables and cereals, by established groups of substances with a general effect mode / mechanism.

Ecological and hygienic aspects of cervical erosion in rural women of the Republic of Dagestan

Based on the available results of the conducted studies, it can be said that the current level of influence of negative environmental factors has exceeded the critical level of the adaptive capabilities of the body of women of fertile age. This determines the fundamental applied importance of identifying the influence of individual factors and the consequences of the use of pesticides on the incidence of cervical erosion, which is an endogenous risk factor for the development of malignant neoplasms of the cervix. In the course of the work, an assessment was made of the independent, total and combined effect of mineral fertilizers and agrochemicals on indicators of the incidence of cervical erosion in women in rural areas of the Republic of Dagestan, since they are the leading environmental factors. A two-way analysis of variance was carried out for the influence of the place of residence and the intensity of the use of mineral fertilizers and agrochemicals. In total, information was obtained on the effect of over 600 combinations of mineral fertilizers and pesticides on the incidence of cervical erosion in women in rural areas of the Republic of Dagestan. The influence of natural and anthropogenic ecological and hygienic factors in the Republic of Dagestan on the incidence of cervical erosion (ESM) in the adult female population, especially in rural areas of the republic, was established. The analyzed data on the impact of the use of mineral fertilizers and pesticides demonstrate that in rural regions, where there is an intensive rate of development of agriculture with the use of mineral fertilizers and pesticides, it is necessary to take them into account as real risk factors for the development of cervical erosion in women. The results of the study give grounds to assume the presence of an indirect influence of the considered environmental factors on the incidence of cervical erosion.

Determination of Pesticides in Bee Pollen: Validation of a Multiresidue High-Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry Method and Testing Pollen Samples of Selected Botanical Origin.

Pollen is a source of nutrients for honeybees (Apis mellifera L.) and suitable for human consumption as well. In our research, a multiresidue method for pesticide determination was developed and validated for the bee pollen matrix. 247 components met the validation criteria for limit of detection, limit of quantification, linearity, and interday repeatability. Average recoveries varied between 70 and 120% except for 14 analytes, which were corrected during on-going validation. The matrix effect was strong for certain analytes, which required the use of matrix-matched calibration. The pesticide residue profiles of 21 pollen samples of different botanical origins were identified by the developed method. The most common active substances were chlorpyrifos, thiacloprid, and acetamiprid. Some products contained pesticides that are already banned. According to our estimates, the tested samples do not pose an acute risk on honeybees, although the combination of pesticides may cause synergistic toxicity.

Substitution or complementarity: why do rice farmers use a mix of biopesticides and chemical pesticides in China?

Although scholars have become increasingly concerned about finding ways to encourage more farmers to use biopesticides and fewer to use chemical pesticides, few studies have investigated the prevalence of Chinese rice farmers' mixed use of biopesticides and chemical pesticides for pest management. Based on a household survey in Hubei Province, China, this study found that 59.18% of the sample rice farmers used a mix of biopesticides and chemical pesticides. There is mainly a complementarity relationship between rice farmers' decision to use biopesticides and chemical pesticides. The pursuit of multiple production purposes is the main reason why farmers decide on the mixed-use of pesticides. Specifically, farmers generally tend to use biopesticides to ensure food safety for consumption, and chemical pesticides to reduce costs for profitability. The decision of farmers to mix pesticides has led to an increase of pesticide varieties and costs. However, it reduces the frequency of pesticide use, and does not result in a significant increase in rice yield and output value. While food safety should be emphasized in working towards greater use of biopesticides, rice farmers' mixed use of biopesticides and chemical pesticides will remain for a long time until the biotechnology is more developed. In fact, programs that investigate the effects of a combination of biopesticides and chemical pesticides should be implemented to achieve pesticide reduction, because biopesticides and chemical pesticides have specific disadvantages. © 2022 Society of Chemical Industry.

Ototoxicity of an association of insecticides compounds containing dichlorvos and cypermethrin in Wistar rats

Purpose: to evaluate possible ototoxicity secondary to exposure to a combination of pesticides (dichlorvos and cypermethrin based insecticides). Methods: the Wistar rats were divided into 3 groups (12 animals per group): control (water), positive control for hearing damage (cisplatin) and experimental (exposed to dichlorvos and cypermethrin). The amplitude of distortion product otoacoustic emissions was assessed before and after the exposure. Systemic toxicity signs were also evaluated (clinical signs, weight gain and plasma cholinesterase). Wilcoxon test analyzed the post-exposure amplitudes compared to pre-exposure and Kruskal Wallis following Dunn’s post hoc tests analyzed the amplitudes’ variation. Normally distributed variables were evaluated by Student's t test. Results: body weight and plasma cholinesterase values were similar comparing the pre and post exposure in the experimental group. The control group did not manifest significant amplitude reduction of otoacoustic emissions between the pre and post evaluation. In the group exposed to cisplatin there was a significant reduction in amplitudes at 12 kHz on the right (p = 0.006; Wilcoxon) and 4 kHz on the left (p = 0.032; Wilcoxon). In the group exposed to pesticides, there was a significant reduction in the right ear at 4 kHz (p = 0.034; Wilcoxon) and 8 kHz (p = 0.019; Wilcoxon) and in the left ear at 4 kHz (p = 0.007; Wilcoxon), 6 kHz (p = 0.023; Wilcoxon), 8 kHz (p = 0.045; Wilcoxon) and 12 kHz (p = 0.028; Wilcoxon). Conclusion: there was ototoxicity in the experimental group, without a relevant systemic toxicity.

In vitro cytotoxicity and genotoxicity of single and combined pesticides used by Bolivian farmers.

We previously showed that farmers in Bolivia are exposed to many pesticides, some at elevated levels, and that this was associated with increased risk of genetic damage. To improve the understanding of possible mixture effects, the cytotoxicity and genotoxicity of pesticides were studied in vitro using human liver HepG2 cells. The studied pesticides were 2,4-D, chlorpyrifos, cypermethrin, glyphosate, methamidophos, paraquat, profenofos, and tebuconazole. Three mixtures (U1, U2, and U3) were based on profiles of urinary pesticide metabolites and one mixture on the most frequently used pesticides (S1). The results showed that paraquat and methamidophos were the most cytotoxic pesticides (EC50 ≤0.3 mM). Paraquat, chlorpyrifos, tebuconazole, and the U1, U2, and U3 mixtures, which contained a large proportion of either chlorpyrifos or tebuconazole, significantly increased intracellular ROS levels. Most pesticides activated DNA damage signaling through proteins Chk1 and H2AX. Strongest responses were elicited by paraquat, profenofos, chlorpyrifos, cypermethrin, and the S1 mixture, which contained 25% paraquat. Comet assay revealed significant increases of DNA damage in response to paraquat, cypermethrin, and U2 and S1 mixtures, which contained high levels of cypermethrin and paraquat, respectively. In summary, we showed that the tested pesticides, alone or in mixtures, in general induced oxidative stress and that most pesticides, and especially paraquat and cypermethrin, were genotoxic in HepG2 cells. We could also show that mixtures dominated by these two pesticides displayed a marked genotoxic potency, which agreed with our previous population studies.

Chronic sublethal pesticide exposure affects brood production, morphology and endosymbionts, but not immunity in the ant, Cardiocondyla obscurior

Abstract Insect diversity and biomass have been declining around the world. This might have severe consequences on the environment since insects provide many crucial ecosystem services. One major driver behind the decline is continuous pesticide use which also affects nontarget organisms. Even at low doses, chronic exposure to pesticides may have negative long‐term effects. Ants have not received much attention in this context, despite their importance in terrestrial ecosystems. A full factorial experimental design was used to test how ingestion of two widely used pesticides influence colonies of the ant Cardiocondyla obscurior. Colonies were exposed for 12 weeks to the herbicide glyphosate and the neonicotinoid insecticide thiacloprid, separately and in combination. Brood production and the size of new workers and queens produced in these colonies were measured. In addition, the relative densities of two endosymbionts were quantified and immunocompetence tested by measuring survival after fungal infection. The two pesticides in combination decreased brood production, which was measured as the number of produced eggs and pupae. Workers and queens produced in pesticide‐exposed colonies differed in body size from individuals produced in control colonies. Furthermore, endosymbiont densities decreased after glyphosate exposure. Neither pesticide influenced survival after fungal infection. The results show that chronic exposure to two widely used pesticides causes apparent trade‐offs in reproduction and other physiological traits of ants, potentially decreasing fitness. Even low levels of pesticides in the environment may therefore have negative effects on ant colonies, contributing to the worldwide insect decline.

Combined Developmental Toxicity of the Pesticides Difenoconazole and Dimethomorph on Embryonic Zebrafish.

Difenoconazole (DIF) and dimethomorph (DIM) are widely used pesticides frequently detected together in environmental samples, so the deleterious effects of combined exposure warrant detailed examination. In this study, the individual and combined effects of DIM and DIF on conventional developmental parameters (hatching rate, deformity rate, lethality) and gene expression were measured in embryonic zebrafish. Both DIF and DIM interfered with normal zebrafish embryo development, and the most sensitive toxicity index for both was 96 h post-fertilization (hpf) deformity rate (BMDL10 values of 0.30 and 1.10 mg/L, respectively). The combination of DIF and DIM had mainly synergistic deleterious effects on 96 hpf deformity and mortality rates. Transcriptome analysis showed that these compounds markedly downregulated expression of mcm family genes, cdk1, and cdc20, thereby potentially disrupting DNA replication and cell cycle progression. Enhanced surveillance for this pesticide combination is recommended as simultaneous environmental exposure may be substantially more harmful than exposure to either compound alone.

The silence of the clams: Forestry registered pesticides as multiple stressors on soft-shell clams

Contaminants are ubiquitous in the environment, often reaching aquatic systems. Combinations of forestry use pesticides have been detected in both water and aquatic organism tissue samples in coastal systems. Yet, most toxicological studies focus on the effects of these pesticides individually, at high doses, and over acute time periods, which, while key for establishing toxicity and safe limits, are rarely environmentally realistic. We examined chronic (90 days) exposure by the soft-shell clam, Mya arenaria, to environmentally relevant concentrations of four pesticides registered for use in forestry (atrazine, 5 μg/L; hexazinone, 0.3 μg/L; indaziflam, 5 μg/L; and bifenthrin, 1.5 μg/g organic carbon (OC)). Pesticides were tested individually and in combination, except bifenthrin, which was tested only in combination with the other three. We measured shell growth and condition index every 30 days, as well as feeding rates, mortality, and chemical concentrations in tissue from a subset of clams at the end of the experiment to measure contaminant uptake. Indaziflam caused a high mortality rate (max. 36%), followed by atrazine (max. 27%), both individually as well as in combination with other pesticides. Additionally, indaziflam concentrations in tissue (61.70–152.56 ng/g) were higher than those of atrazine (26.48–48.56 ng/g), despite equal dosing concentrations, indicating higher tissue accumulation. Furthermore, clams exposed to indaziflam and hexazinone experienced reduced condition index and clearance rates individually and in combination with other compounds; however, the two combined did not result in significant mortality. These two compounds, even at environmentally relevant concentrations, affected a non-target organism and, in the case of the herbicide indaziflam, accumulated in clam tissue and appeared more toxic than other tested pesticides. These findings underscore the need for more comprehensive studies combining multiple compounds at relevant concentrations to understand their impacts on aquatic ecosystems.

Varying impact of neonicotinoid insecticide and acute bee paralysis virus across castes and colonies of black garden ants, Lasius niger (Hymenoptera: Formicidae)

Pesticides and pathogens are known drivers of declines in global entomofauna. However, interactions between pesticides and viruses, which could range from antagonistic, over additive to synergistic, are poorly understood in ants. Here, we show that in ants the impact of single and combined pesticide and virus stressors can vary across castes and at the colony level. A fully-crossed laboratory assay was used to evaluate interactions between a sublethal dose of the neonicotinoid thiamethoxam and Acute bee paralysis virus (ABPV) in black garden ants, Lasius niger. After monitoring colonies over 64 weeks, body mass, neonicotinoid residues and virus titres of workers and queens, as well as worker behavioural activity were measured. ABPV, but not thiamethoxam, reduced activity of workers. Neonicotinoid exposure resulted in reduced body mass of workers, but not of queens. Further, thiamethoxam facilitated ABPV infections in queens, but not in workers. Overall, virus exposure did not compromise detoxification and body mass, but one colony showed high virus titres and worker mortality. Although the data suggest additive effects at the level of individuals and castes, co-exposure with both stressors elicited antagonistic effects on colony size. Our results create demand for long-term holistic risk assessment of individual stressors and their interactions to protect biodiversity.

Performance Standards and Acceptable Test Conditions for Preventive Termiticide and Insecticide Treatments, Termite Baiting Systems, and Physical Barriers for New Structures or Buildings under Construction (Pre-Construction; During Construction; Post-Construction)

Florida Administrative Code (FAC) 5E-2.0311, “Performance Standards and Acceptable Test Conditions for Preventive Termite Treatments for New Construction,” approved in 2003, currently remains without change as originally written. This Code requires broad revision to include updating existing and new termite management methods and technologies, describing acceptable testing protocols that objectively evaluate termite management product efficacy, and clearly and accurately define product performance standards required for approval and use in Florida, USA. This manuscript provides modification and expansion of the existing Code, first in outline form, then followed by a proposed complete revision including detailed explanations for each outline heading and sub-heading. Efficacy requirements, acceptable test conditions, and performance standards requirements are described for termite management products, materials, and non-chemical physical exclusion barriers. We also include testing protocols for field plot and structure efficacy tests. Minimum performance standards also are described for field plots and structure tests to include: (1) termiticide applications to soil, (2) termite baiting systems, (3) pesticides applied directly to wood and building components, (4) pesticide combination mixtures, and (5) new application technologies, products, and methodologies. Although this manuscript addresses revision of a specific Florida Administrative Code, it also is appropriate for consideration by the United States Environmental Protection Agency (USEPA) as well as regulatory entities in other states responsible for pesticide regulation and consumer protection services when writing or revising their code requirements for termite management.

The study of primary DNA damage in the bone marrow of mice under the combined action of pesticides

Introduction. The study of the potential negative effects of combinations of several pesticide active ingredients is an important and understudied area of toxicological and hygienic research. The initial phase of the genotoxicant action on the genetic structures in cells is the primary DNA damage, the identification of which makes it possible to assess the early stages of the genotoxic effect of xenobiotics and their mixtures. The DNA comet assay is widely used for these purposes. The aim of the research is to assess the primary DNA damage under the combined action of pesticides. Materials and methods. To assess DNA damage the experiments on CD-1 mice of both sexes were performed using alkaline comet analysis. The concentration of active products reacting with thiobarbituric acid (TBA) in the blood serum of white outbred rats was assessed as a marker of lipid peroxidation. Results. It was found that mixtures of 2,4-D-acid + glyphosate and thiram + carbendazim did not cause the formation of breaks and alkali-labile sites in the DNA of mice bone marrow cells. Exposure to the combination of the technical grade active ingredients captan and fludioxonil induced the breaks and alkali-labile sites in the DNA of animal bone marrow cells. The comparison of the genotoxicity assessment results obtained by the comet assay and results of analysis of the TBA-active product concentrations in the rat blood serum suggests that the observed primary DNA damage upon exposure to the captan and fludioxonil combination can be mediated by the induction of lipid peroxidation and subsequent interaction of the resulting products with nucleic acids. Conclusion. The results indicate that some pesticides in combination can damage hereditary material in mammalian cells. Therefore, in order to ensure the safe use of pesticides for public health it is necessary to take into account the data on the genotoxicity not only of individual pesticide technical grade active ingredients but also their combinations.

Widespread agrochemicals differentially affect zooplankton biomass and community structure.

Anthropogenic environmental change is causing habitat deterioration at unprecedented rates in freshwater ecosystems. Despite increasing more rapidly than many other agents of global change, synthetic chemical pollution-including agrochemicals such as pesticides-has received relatively little attention in freshwater community and ecosystem ecology. Determining the combined effects of multiple agrochemicals on complex biological systems remains a major challenge, requiring a cross-field integration of ecology and ecotoxicology. Using a large-scale array of experimental ponds, we investigated the response of zooplankton community properties (biomass, composition, and diversity metrics) to the individual and joint presence of three globally widespread agrochemicals: the herbicide glyphosate, the neonicotinoid insecticide imidacloprid, and nutrient fertilizers. We tracked temporal variation in zooplankton biomass and community structure along single and combined pesticide gradients (each spanning eight levels), under low (mesotrophic) and high (eutrophic) nutrient-enriched conditions, and quantified (1) response threshold concentrations, (2) agrochemical interactions, and (3) community resistance and recovery. We found that the biomass of major zooplankton groups differed in their sensitivity to pesticides: ≥0.3mg/L glyphosate elicited long-lasting declines in rotifer communities, both pesticides impaired copepods (≥3µg/L imidacloprid and ≥5.5mg/L glyphosate), whereas some cladocerans were highly tolerant to pesticide contamination. Strong interactive effects of pesticides were only recorded in ponds treated with the combination of the highest doses. Overall, glyphosate was the most influential driver of aggregate community properties of zooplankton, with biomass and community structure responding rapidly but recovering unequally over time. Total community biomass showed little resistance when first exposed to glyphosate, but rapidly recovered and even increased with glyphosate concentration over time; in contrast, taxon richness decreased in more contaminated ponds but failed to recover. Our results indicate that the biomass of tolerant taxa compensated for the loss of sensitive species after the first exposure, conferring greater community resistance upon a subsequent contamination event; a case of pollution-induced community tolerance in freshwater animals. These findings suggest that zooplankton biomass may be more resilient to agrochemical pollution than community structure; yetall community properties measured in this study were affected at glyphosate concentrations below common water quality guidelines in North America.

Synergistic effects of contaminants in Lombardy waters

Quantifying synergistic environmental effects in water contamination is still an open issue. Here, we have analyzed geolocalized data of pollutants recorded in 2018 in surface and groundwater of Lombardy, one of the areas with the highest agricultural production rates, not only in Italy, but also in Europe. Both herbicides and insecticides are present at concentration levels above the legal limit, mainly in surface waters. Geolocalized analysis allows us to identify interesting areas particularly affected by a combination of multiple pesticides. We thus investigated possible synergistic effects of these compounds on the environment, using the alga C. reinhardtii as a biosensor. Our results show that exposure for 7 days to four compounds, that we found present together at high concentration in surface waters, was able to induce a stress in the algae, as indicated by the presence of palmelloids. Our work results in a pipeline that could easily be exported to monitor other territories in Italy and abroad.