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Waste liquid mercury generated as a by-product of the Merrill-Crowe process in gold mining and recovered from mercury-containing waste must be stabilized for secure storage or disposal. This study developed a procedure for mercury stabilization. A ball mill with a 0.5 m3 capacity and a rotational speed of 43 rpm was used to stabilize the residual mercury with sulfur. The treatments were conducted for 30, 60, and 90 min at mercury: sulfur molar ratios of 1.0, 0.8, and 0.67. The ball loading ratio was 7.0 with residual mercury, and the temperature was below 40 °C. The treatment efficiency was evaluated by measuring the concentrations of mercury and other metals using the Toxicity Characteristic Leaching Procedure (TCLP), examining the stabilized residual mercury by X-ray diffraction, and conducting bioassays on Daphnia magna and Lactuca sativa. Principal component analysis (PCA) was performed on the aforementioned variables. The 90-min treatment, with a mercury-to-sulfur molar ratio of 0.67, stabilized mercury mainly as cinnabar compared with the other treatments and presented leachate mercury values below the detection limit <0.003. The leachate from the treatments also showed values of 21.28-38.44 toxic units, classified as very toxic, and generated toxicity, particularly for D. magna, because of the presence of other metals such as Al, Ba, B, Ca, Cu, Cr, Fe, Mn, Ni, and Zn. The variability of the residues in the PCA analysis was explained by the treatment effect and the presence of other metals in the residual mercury. The stabilized residual mercury obtained was classified as non-hazardous and could be stored or disposed of as ordinary waste in a security landfill.

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Heavy metals pose a significant threat to animals in aquatic environments due to the adverse effects they exert. Species of the genus Artemia have been described as heavy metal tolerant, but the sensitivity/tolerance range for these species has not been established. In the present study, the toxicity of Cd, Cu, Zn and Ni as reported in the ECOTOX and Web of Science databases was examined for Artemia franciscana and compared with other species and taxonomic groups using an integrative ecotoxicity evaluation. The hazard concentration for 5% of the species (HC5) of acute toxicity tests (24-96 h), obtained through a species sensitivity distribution (SSD) indicated that Cu (0.02 mg/L) and Cd (0.03 mg/L) were the metals with the highest toxicity to aquatic animals followed by Zn (0.15 mg/L) and Ni (0.23 mg/L). In addition to the higher hazard of Cu and Cd to aquatic animals, the comparison of acute LC50 values for A. franciscana indicates lower toxicity of Cd followed by Cu, Zn, and Ni (200.0, 14.5, 9.5, and 0.6 mg/L, respectively). Using the SSD and physiological sensitivity (S) approaches, it was demonstrated that A. franciscana is relatively tolerant to Cd (SSD= HC99; S = 2.21), Cu (SSD= HC97; S = 2.00), Zn (SSD= HC90; S = 1.29) and Ni (SSD= HC83; S = 0.96) compared with other species and taxonomic groups. It appears that tolerance to the metals Cd, Cu, Zn and Ni is unique to the family Artemiidae within the order Anostraca, as the families Streptocephalidae and Thamnocephalidae are not tolerant (have negative S values). Our study confirmed that as expected, A. franciscana presents higher tolerance to Cd, Cu, Zn, and Ni than other aquatic animals. Our findings confirm that A. franciscana can be used as a model organism to understand mechanisms involved in tolerance to heavy metals, mainly Cd and Cu, which are considered highly toxic to other animals.

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The aim of this study was to determine the acute toxicity of the essential oils (EOs) of Aloysia triphylla, Lippia gracilis and Piper aduncum in juvenile tambaqui (Colossoma macropomum), and evaluate the possible histopathological alterations in their gills. For the acute toxicity tests, juvenile tambaqui (n=24/treatment) were distributed in six treatments with three replicates, which comprised the control and five EO concentrations of A. triphylla (60, 80, 100, 120 and 140 mg L-1), L. gracilis (35, 40, 45, 50 and 55 mg L-1) and P. aduncum (42.5, 45, 47.5, 50 and 52.5 mg L-1), with an exposure period of 4 h. The mortality rate and severity of damage to the tambaqui gills were proportional to the increase in the concentration of the EO, with LC50-4 h values estimated at 109.57 mg L -1 for A. triphylla, 41.63 mg L -1 for L. gracilis and 48.17 mg L -1 for P. aduncum. The main morphological damages observed in the gills of the tambaqui exposed to the three EOs, were Grade I: hypertrophy and hyperplasia of lamellar epithelial cells, lamellar fusion, epithelial detachment, capillary dilation and constriction, proliferation of chloride cells and mucosal cells and edema; in low frequency Grade II damage as epithelial rupture and lamellar aneurysm. Necrosis (Grade III damage) was observed only in gill lamellae exposed to P. aduncum EO (47.5, 50.0 and 52.5 mg L-1). Concentrations of EOs below LC50-4 h can be used sparingly, for short periods of exposure for the treatment of diseases in tambaqui breeding.

O objetivo deste estudo foi determinar a toxicidade aguda dos óleos essenciais (OEs) de Aloysia triphylla, Lippia gracilis e Piper aduncum em juvenis de tambaqui (Colossoma macropomum), e avaliar as possíveis alterações histopatológicas em suas brânquias. Para os testes de toxicidade aguda, juvenis de tambaqui (n=24/tratamento) foram distribuídos em 6 tratamentos, com três repetições, sendo o controle e cinco concentração do OE de A. triphylla (60, 80, 100, 120 e 140 mg L-1), L. gracilis (35, 40, 45, 50 e 55 mg L-1) e P. aduncum (42,5, 45, 47,5, 50 e 52,5 mg L-1), com exposição de 4 h. A taxa de mortalidade e a severidade dos danos nas brânquias de tambaqui foram proporcionais ao aumento da concentração do OE, com os valores de CL50-4 h estimados em 109,57 mg L-1 para A. triphylla, em 41,63 mg L-1 para L. gracilis e em 48,17 mg L-1 para P. aduncum. Os principais danos morfológicos observados nas brânquias de tambaqui, expostos aos três OEs, foram os de grau I: hipertrofia e hiperplasia das células do epitélio lamelar, fusão lamelar, descolamento epitelial, dilatação e constrição capilar, proliferação de células de cloreto e de células mucosas e edema; em baixa frequência os de grau II como ruptura epitelial e aneurisma lamelar. Necrose (dano de grau III) foi observado somente nas lamelas branquiais expostas ao OE de P. aduncum (47,5, 50,0 e 52,5 mg L-1). Concentrações do OEs abaixo dos valores de CL50-4 h podem ser utilizados com parcimônia, em curtos períodos de exposição para o tratamento de doenças na criação de tambaqui.

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Emerging contaminants such as sunscreens, hair dyes and flame retardants have been found at important concentrations in surface water (river, lake, ocean), but their negative impact on different aquatic species is not fully known. This study evaluated the effect of benzophenone (BZ), 2,5-diaminotoluene sulfate (PTD), p-phenylenediamine (PPD) and tetrabromobisphenol A (TBPA) on survival (LC50) and the impact of sublethal concentrations (LC25) on the activity of enzymes linked to stress oxidative process in brine shrimp under two temperature conditions (22 °C and 28 °C) for 24 h and 48 h of exposure time. LC50 values obtained for each chemical substance and the activity of GST, AChE and LDH were significantly affected by the temperature conditions and exposure time. In contrast, GPx was only altered by the tested compound. TBBPA (LC50 from 17.05 up to 28.55 µg/L) and BZ (LC50 from 14.86 up to 24.49 mg/L) resulted in the most toxic substances for A. salina. The impact of dyes, such as PTD and PPD, on aquatic organisms is limited. These are the first results that show that not only dyes, but their respective by-products induce harmful effects in brine shrimp (LC50 for PTD and PPD were 23.6-396.3 and 52.0-164.9 mg/L respectively). Although this study model was very useful to evaluate the ecotoxicity of the different ECs, additional research is needed to increase available information related to the effects of dyes and other non-studied micropollutants on aquatic systems in general.

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The first step for biological insecticide production is the evaluating of the pathogenicity and strains virulence of entomopathogens against the target pests. Bacillus thuringiensis (Bt) is widespread in nature, lethal pathogen of a range of orders and the most widely used entomopathogenic biological control agent. Therefore, our objective was to study the susceptibility of six important lepidopteran pests in Brazilian agricultural production systems, Anticarsia gemmatalis (Hübner), Chrysodeixis includens (Walker) Helicoverpa armigera (Hübner), Spodoptera cosmioides (Walker), S. eridania (Cramer), and S. frugiperda (Smith), to Bt strains. In vitro bioassays were conducted with neonate larvae exposed to two Bt strains, 1680A and 775E, in seven concentrations of spores and protein crystals. After 7 days, the mortality was evaluated and indicated that lethal concentration (LC50) for 775E strain ranged from 7.72 × 104 to 2.45 × 106 spores mL-1 and for 1608A strain from 5.63 × 103 to 1.21 × 106 spores mL-1. The strain 1608A was more toxic for A. gemmatalis and H. armigera than 775E strain, and then was further evaluated in greenhouse bioassays with maize and soybean plants infested separately with target insects. The strain 1608A showed an efficient control for most insect species studied in the greenhouse bioassays, promoting considerable reduction in leaf injury and demonstrating a high potential in biological control of important lepidopteran species in crop production systems in Brazil.

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Palmistichus elaeisis Delvare and LaSalle 1993 (Hymenoptera: Eulophidae) and neem oil are two control alternatives for the integrated management of defoliating lepidopterans. The aim of this study was to evaluate the acute and chronic toxicity of neem oil compared to the synthetic insecticide deltamethrin, on the endoparasitoid P. elaeisis, in generations F0, F1, F2, and F3. Females of P. elaeisis were exposed to neem solutions at concentrations of 0, 1.87, 3.75, 7.50, 15.00, 30.00, and 60.00 mg ml-1, to determine the dose-response relationship and estimate the neem LC50. The sublethal effects on the parasitoid P. elaeisis in generations F0 to F3 were evaluated with these same concentrations of neem and 0.033 mg ml-1 of deltamethrin. The neem LC50 was estimated at 3.92 mg ml-1. The LC50 for P. elaeisis is 3.83 times lower than that recommended by the neem manufacturer for pest control, demonstrating high acute toxicity to this natural enemy. The chronic toxicity of both the commercial dose and those below it to P. elaeisis caused low sublethal effects. The correct concentration of neem oil in pest control is important, and its use should be performed with caution in integrated pest management programs using the endoparasitoid P. elaeisis to avoid causing interference between the two pest control techniques.

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Hypocrella, Moelleriella and related species in the Hypocreales (Ascomycota, Sordariomycetes) cause epizootics of whiteflies and scale insects in nature. However, studies on their host specificity, virulence, infection cycles, optimal development under laboratory conditions, and compatibility with other control methods, are unexplored for most species. Under laboratory conditions, the virulence of several isolates of field-collected hypocrealean fungi (Hypocrella, Moelleriella, Regiocrella, and Verticillium) was determined on Bemisia tabaci eggs and 4th instar nymphs. In addition to virulence, the effect of temperature and two commercial fungicides on growth rates and germination of the isolates was evaluated. None of the isolates infected the eggs, while M. libera, M. ochracea, and M. turbinata caused high nymphal mortality. Moelleriella libera was the most virulent isolate. At all temperatures, M. libera, Regiocrella sp. (P17H20), and Verticillium cf. pseudohemipterigenum had the highest germination and growth rates. The optimal growth temperature depended on the isolate, but at 23 °C and 25 °C, the probability of spore germination was higher for most isolates. Finally, the fungicides azoxystrobin and chlorothalonil inhibited growth rates and conidial germination at 24 and 48 h of exposure. This research produces vital knowledge on the virulence and infection cycles of poorly studied native species of entomopathogenic fungi. In addition, the results provide information on the optimal temperature for development in laboratory conditions and susceptibility to fungicides, which could contribute to future biological control strategies.

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Neotropical fish Cnesterodon decemmaculatus were exposed to different sublethal concentrations (0.5, 1.0 and 5.0 mg As/L) of sodium arsenite (As III) to determine the median lethal concentration (LC50; 96 h) and to evaluate the response of a set of biomarkers (genotoxic, behavioral, biochemical, and metabolic). At the end of the exposure (96 h), fish were video-recorded for behavior assessment. We used the micronucleus and nuclear abnormality tests and the comet assay in peripheral blood as genotoxicity biomarkers. In regard to biochemical and metabolic biomarkers, we dissected the brain for acetylcholinesterase (AChE) activity; the liver for glutathione-S-transferase (GST) and catalase (CAT) activity and glutathione content (GSH); the gills for GSH content; and muscle for AChE, energy metabolism of lipids, carbohydrates, and proteins, and the electron transport system activity of the mitochondrial chain. We calculated an index using metabolic biomarkers, to determine the cellular energy allocation. The LC50 value was 7.32 mg As/L. The As affected some swimming parameters in females. No significant differences in micronucleus were found compared with the control, whereas nuclear aberrations increased significantly at 1.0 and 5.0 mg As/L. The genomic damage index and the percentage of cells with DNA damage (measured by the comet assay) showed a significant increase in the As-treated groups, and this technique was the most sensitive for detecting genotoxic damage. The As affected the antioxidant system (mainly GSH, CAT, and GST) and reduced the lipid content. A preliminary baseline was generated for the response of C. decemmaculatus exposed to sublethal concentrations of As, when it alters swimming behavior and the antioxidant system, has genotoxic effects, and reduces lipid content. Environ Toxicol Chem 2022;41:1246-1259. © 2022 SETAC.

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BACKGROUND: The potential of Beauveria bassiana and Metarhizium anisopliae isolates obtained from naturally infected oil palm pests was evaluated to control Demotispa neivai as an alternative for organophosphate insecticide use in oil palm crops in Latin America. Two B. bassiana (Bb-0018 and Bb-0025) and two M. anisopliae (Ma-0002 and Ma-0003) isolates were tested against D. neivai adults for hydrophobicity, virulence, survival, adhesion to host cuticle, and mortality in semi-field conditions. RESULTS: Concentration-mortality bioassays demonstrate that isolates had lethal effect on D. neivai adults with Bb-0025 [median lethal concentration (LC50 ) = 3.45 × 107 conidia mL-1 ] and Bb-0018 (LC50  = 3.75 × 107 conidia mL-1 ) being the most effective followed by Ma-0003 (LC50  = 3.38 × 108 conidia mL-1 ) and Ma-0002 (5.33 × 108 conidia mL-1 ). Adult survival was 99% without exposure to fungal isolates, decreasing to 21.65% in insects exposed to Ma-0002, 19.41% with Ma-0003, 20.13% with Bb-0018, and 0.17% with Bb-0025. Mortality of D. neivai adults caused by the entomopathogenic fungal isolates was similar in both laboratory and semi-field conditions. Also, vegetative growth of the entomopathogenic fungal isolates was found in infected D. neivai adults in the field. CONCLUSION: Our data suggest that the tested entomopathogenic fungal isolates are effective against D. neivai with potential to be used as biological control agents contributing to the decrease of the use of chemical insecticides to control this oil palm pest. © 2021 Society of Chemical Industry.

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Trypanosoma cruzi is the agent of Chagas disease, an infection that affects around 8 million people worldwide. The search for new anti-T. cruzi drugs are relevant, mainly because the treatment of this disease is limited to two drugs. The objective of this study was to investigate the trypanocidal and cytotoxic activity and elucidate the chemical profile of extracts from the roots of the Lonchocarpus cultratus. Roots from L. cultratus were submitted to successive extractions with hexane, dichloromethane, and methanol, resulting in LCH, LCD, and LCM extracts, respectively. Characterization of extracts was done using 1H-RMN, 13C-RMN, CC and TLC. Treatment of T. cruzi forms (epimastigotes, trypomastigotes, and amastigotes) with crescent concentrations of LCH, LCD, and LCM was done for 72, 48, and 48 h, respectively. After this, the percentage of inhibition and IC50/LC50 were calculated. Benznidazole was used as a positive control. Murine macrophages were treated with different concentrations of both extracts for 48 h, and after, the cellular viability was determined by the MTT method and CC50 was calculated. The chalcones derricin and lonchocarpine were identified in the hexane extract, and for the first time in the genus Lonchocarpus, the presence of a dihydrolonchocarpine derivative was observed. Other chalcones such as isocordoin and erioschalcone B were detected in the dichloromethane extract. The dichloromethane extract showed higher activity against all tested forms of T. cruzi than the other two extracts, with IC50 values of 10.98, 2.42, and 0.83 µg/mL, respectively; these values are very close to those of benznidazole. Although the dichloromethane extract presented a cytotoxic effect against mammalian cells, it showed selectivity against amastigotes. The methanolic extract showed the lowest anti-T. cruzi activity but was non-toxic to peritoneal murine macrophages. Thus, the genus Lonchocarpus had demonstrated in the past action against epimastigotes forms of T. cruzi but is the first time that the activity against infective forms is showed, which leading to further studies with in vivo tests.

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This paper shows the results of a dose-response study in Scaptotrigona bipunctatabees, Lepeletier, 1836 (Hymenoptera: Apidae) exposed to the insecticide Fastac Duo. The aim was to evaluate the lethal concentration that causes the death of 50% of bees (LC50) and investigate the odd of mortality after exposure to different concentrations, using the logistic regression model under the Bayesian approach. In this approach, it is possible to incorporate a prior information and gives more accurate inferential results. Three independent dose-response experiments were analyzed, dissimilar in their lead time according to guidelines from the Organisation for Economic Co-operation and Development (OECD), in which each assay contained four replicates at the concentration levels investigated, including control. Observing exposure to the agrochemical, it was identified that the higher the concentration, the greater the odd of mortality. Regarding the estimated lethal concentrations for each experiment, the following values were found, 0.03 g a.i. L-1, for 24hours, 0.04 g a.i. L-1, for 48hoursand 0.06 g a.i. L-1for 72hours, showing that in experiments with longer exposure times there was an increase in LC50. Concluding, the study showed an alternative approach to classical methods for dose-response studies in Scaptotrigona bipunctatabees exposed to the insecticide Fastac Duo.(AU)

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This paper shows the results of a dose-response study in Scaptotrigona bipunctatabees, Lepeletier, 1836 (Hymenoptera: Apidae) exposed to the insecticide Fastac Duo. The aim was to evaluate the lethal concentration that causes the death of 50% of bees (LC50) and investigate the odd of mortality after exposure to different concentrations, using the logistic regression model under the Bayesian approach. In this approach, it is possible to incorporate a prior information and gives more accurate inferential results. Three independent dose-response experiments were analyzed, dissimilar in their lead time according to guidelines from the Organisation for Economic Co-operation and Development (OECD), in which each assay contained four replicates at the concentration levels investigated, including control. Observing exposure to the agrochemical, it was identified that the higher the concentration, the greater the odd of mortality. Regarding the estimated lethal concentrations for each experiment, the following values were found, 0.03 g a.i. L-1, for 24hours, 0.04 g a.i. L-1, for 48hoursand 0.06 g a.i. L-1for 72hours, showing that in experiments with longer exposure times there was an increase in LC50. Concluding, the study showed an alternative approach to classical methods for dose-response studies in Scaptotrigona bipunctatabees exposed to the insecticide Fastac Duo.

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Diaphania hyalinata (Linnaeus, 1767) is one of the main pests of the cucurbit crops. Biological control and botanicals are used in integrated pest management (IPM), especially in agro-ecological agricultures where the use of synthetic pesticides is restricted. Toxicological effects of plant essential oils on target and nontarget organisms should be evaluated to determine its use in IPM. The toxicity of ginger, peppermint, oregano, and thyme essential oils to D. hyalinata eggs, larvae, and pupae and their selectivity to the parasitoid Trichospilus pupivorus and the LC50, LC99 and the relative selectivity index (RSI) of these botanicals were determined. The eggs of D. hyalinata were more sensitive to the botanicals applied than its larvae and pupae, with higher toxicity of oregano and thyme essential oils, followed by those of peppermint and ginger. Topical application was the least toxic method to D. hyalinata larvae. Ginger, peppermint, and thyme essential oils were more toxic by ingestion and oregano by contact to D. hyalinata larvae. The essential oil concentrations applied to D. hyalinata pupae prevent the emergence of adults of this insect with the oregano essential oil showing the greatest toxicity. Peppermint, ginger, thyme, and oregano essential oils were selective to T. pupivorus with RSI50 of 5.40, 1.38, 8.15, and 6.98 and RSI99 of 1.54, 2.53, 3.90, and 4.16 respectively. The ginger, peppermint, oregano, and thyme essential oils were toxic to immature D. hyalinata and selective to T. pupivorus females presenting potential as an alternative control in the IPM of this pest in Cucurbitaceae crops.

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Cyanobacteria have been considered a major global threat because of their widespread ability to proliferate and contaminate inland and marine waters with toxic metabolites. For this reason, to avoid risks to humans and environmental health, regulatory legislation and guidelines have been established based on extensive toxicological data. However, most of what is known in this field come from works on microcystin (MC) variants, which effects were almost exclusively tested in metazoan models. In this work, we used acute end-point toxicological assays and high-resolution hybrid quadrupole time-of-flight mass spectrometer coupled with electrospray ionization source (ESI-Q-TOF-MS) analyses to evaluate the deleterious impact of aqueous extracts prepared from cultures of cyanobacteria and environmental bloom biomasses over a non-metazoan model organism, the cosmopolitan fresh/brackish water unicellular microeukaryote, Paramecium caudatum (Ciliophora). Our data suggest that all extracts produced time-dependent effects on P. caudatum survival, irrespective of their metabolite profile; and that this ciliate is more sensitive to extracts containing microginins than to extracts with only MCs, stressing that more toxicological investigations should be performed on the environmental impact of neglected cyanotoxins. Further, our data provide evidence that P. caudatum may be more sensitive to cyanotoxins than vertebrates, indicating that guidelines values, set on metazoans are likely to be inaccurate to protect organisms from basal food web positions. Thus, we highly recommend the widespread use of microeukaryotes, such as ciliates in environmental risk assessment frameworks for the establishment of more reliable cyanotoxin monitoring guideline values.

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Malachite green (MG) is a triphenylmethane dye that is widely used in aquaculture as a fungicide, bactericide, ectoparasiticide, and antiprotozoal. There is great debate regarding the potential for this compound to trigger adverse effects. Here, we review the previous findings and then evaluate the lethal and sublethal effects of MG in the species Hemichromis bimaculatus (jewelfish). The lethal concentration for 50% of the fish in 96 h was 1 mg/L. We observed a dose-dependent increase in the percentage of fish mortality as well as physical and behavioral changes. We further found that the highest tested sublethal dose significantly increased the DNA damage index identified using the comet assay (74.97 ± 13.8 at a significant level of P < 0.05 for the 0.75 mg/L concentration), but did not significantly alter the results of the micronucleus test. Although our results suggest that MG confers risks on exposed fish, the findings were significant only at the highest exposure concentration (0.75 mg/L). At lower concentrations (0.25 mg/L and 0.5 mg/L), no adverse effect was observed. The maximum MG concentration recommended for use in ornamental fish farming is 0.2 mg/L. Therefore, our results suggest that, specifically for the parameters analyzed in this work, MG does not have any adverse effect when users strictly adhere to the recommended concentration criteria for ornamental fish.

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The black cutworm Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) is a cosmopolitan and polyphagous pest that attacks diverse crops and weed. One of the alternatives to insecticides may be the use of bioinsecticides based on Bacillus thuringiensis Berliner (Bt). Thus, the objective of the present study were evaluating the toxicity of Agree® and Dipel® bioinsecticides based on Bt on different larval ages of A. ipsilon. For the experiments, five larval ages were used (0-24, 48-72, 96-120, 144-168, and 192-216 h). The A. ipsilon caterpillars were individualized in acrylic tubes containing an artificial diet and 50 L of each biopesticide in the concentration 1 × 108 spores mL-1. Mortality was assessed for seven days. The two bioinsecticides evaluated promoted mortality at all larval ages of A. ipsilon. The age of 0-24 h had mortality above 90%. The values of LC50 and LC90 were 9.8 × 105 and 7.4 × 106 spores mL-1 for Agree® and 1.3 × 106 e 1.4 × 107 spores mL-1 for Dipel®, respectively, without difference between LC50 and LC90 values of the bioinsecticides. The results indicate that younger caterpillars are more susceptible to Bt-based bioinsecticides.

A lagarta rosca Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) é uma praga cosmopolita e polífaga que ataca diversas culturas e plantas daninhas. Uma das alternativas de manejo ao uso de inseticidas químicos pode ser o uso de bioinseticidas à base de Bacillus thuringiensis Berliner (Bt). Deste modo, o presente trabalho teve por objetivo avaliar a toxicidade dos bioinseticidas Agree® e Dipel® à base de Bt sobre diferentes idades de lagartas de A. ipsilon. Para os experimentos, lagartas de cinco idades foram utilizadas (0-24, 48-72, 96-120, 144-168 e 192-216 horas). As lagartas de A. ipsilon foram individualizadas em tubos de acrílico contendo dieta artificial e 50 µL de cada bioinseticida na concentração 1 × 108 esporos mL-1. A mortalidade foi avaliada durante sete dias. Os dois bioinseticidas avaliados promoveram mortalidade em todas as idades das lagartas de A. ipsilon. Lagartas com idade 0-24 h apresentaram mortalidade acima de 90%. Os valores de CL50 e CL90 foram 9,8 × 105 e 7,4 × 106 esporos mL-1 para Agree® e 1,3 × 106 e 1,4 × 107 esporos mL-1 para Dipel®, respectivamente, sem diferença entre os valores de CL50 e CL90 dos bioinseticidas. Os resultados indicam que lagartas mais jovens são mais suscetíveis aos bioinseticidas à base de Bt.

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The black cutworm Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) is a cosmopolitan and polyphagous pest that attacks diverse crops and weed. One of the alternatives to insecticides may be the use of bioinsecticides based on Bacillus thuringiensis Berliner (Bt). Thus, the objective of the present study were evaluating the toxicity of Agree® and Dipel® bioinsecticides based on Bt on different larval ages of A. ipsilon. For the experiments, five larval ages were used (0-24, 48-72, 96-120, 144-168, and 192-216 h). The A. ipsilon caterpillars were individualized in acrylic tubes containing an artificial diet and 50 L of each biopesticide in the concentration 1 × 108 spores mL-1. Mortality was assessed for seven days. The two bioinsecticides evaluated promoted mortality at all larval ages of A. ipsilon. The age of 0-24 h had mortality above 90%. The values of LC50 and LC90 were 9.8 × 105 and 7.4 × 106 spores mL-1 for Agree® and 1.3 × 106 e 1.4 × 107 spores mL-1 for Dipel®, respectively, without difference between LC50 and LC90 values of the bioinsecticides. The results indicate that younger caterpillars are more susceptible to Bt-based bioinsecticides.(AU)

A lagarta rosca Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) é uma praga cosmopolita e polífaga que ataca diversas culturas e plantas daninhas. Uma das alternativas de manejo ao uso de inseticidas químicos pode ser o uso de bioinseticidas à base de Bacillus thuringiensis Berliner (Bt). Deste modo, o presente trabalho teve por objetivo avaliar a toxicidade dos bioinseticidas Agree® e Dipel® à base de Bt sobre diferentes idades de lagartas de A. ipsilon. Para os experimentos, lagartas de cinco idades foram utilizadas (0-24, 48-72, 96-120, 144-168 e 192-216 horas). As lagartas de A. ipsilon foram individualizadas em tubos de acrílico contendo dieta artificial e 50 µL de cada bioinseticida na concentração 1 × 108 esporos mL-1. A mortalidade foi avaliada durante sete dias. Os dois bioinseticidas avaliados promoveram mortalidade em todas as idades das lagartas de A. ipsilon. Lagartas com idade 0-24 h apresentaram mortalidade acima de 90%. Os valores de CL50 e CL90 foram 9,8 × 105 e 7,4 × 106 esporos mL-1 para Agree® e 1,3 × 106 e 1,4 × 107 esporos mL-1 para Dipel®, respectivamente, sem diferença entre os valores de CL50 e CL90 dos bioinseticidas. Os resultados indicam que lagartas mais jovens são mais suscetíveis aos bioinseticidas à base de Bt.(AU)

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In this study the potential bioinseticide of the essential oil (OE) extracted from the rhizomes of the species Curcuma zedoaria (Zingiberaceae) was evaluated. The rhizomes were collected during dormancy (winter) and budding (summer). The EO was obtained by hydrodistillation (2h) and identified by GC/MS. In addition, a multivariate exploratory analysis was done to determine the analysis of the major compounds (PCA). The EO yield in dormancy was 0.61± 0.07 (%) and in budding 0.55 ± 0.08 (%). The bioassays on Aedes aegypti larvae and pupae were done by immersion test at different EO concentrations which ranged from 500.00 to 0.003 mg mL-1 (v/v). The results on the larvae and pupae indicated LC99.9 of (0.01 and 1.38 mg mL-1) for EO in dormancy, and (0.08 and 2.63 mg mL-1) for EO during budding, respectively. The action mechanism of EOs in both periods was determined by autobiographic method evaluating the inhibitory potential on the acetylcholinesterase enzyme, indicating greater inhibition of the EO enzyme during dormancy (0.039 mg mL-1) when compared to the EO during budding (0.156 mg mL-1). The projection representation of the EO chemical classes in both evaluated periods indicated that oxygenated sesquiterpenes are the major compound class (46.99% in dormancy) and (43.59% in budding). The projection of major chemical compounds of EOs presented three compounds with greater mass flow distancing: epicurzerenone (18.20% and 12.10%); 1.8 cineole (15.76% and 12.10%) and ß-elemene (4.43 and 0.01%) that are found in greater amounts in the dormancy EO when compared to budding, respectively. These results corroborate with the greater potential on Ae. aegypti larvae and pupae found for the dormancy EO. The results are promising because they show in which vegetative cycle phase C. zedoaria EO presents greater bioinsecticidepotential.

Neste trabalho foi avaliado o potencial bioinseticida do óleo essencial (OE) extraído dos rizomas da espécie Curcuma zedoaria (Zingiberaceae), coletados no período de dormência (inverno) e brotação das gemas (verão). O OE foi obtido por hidrodestilação (2h) e identificado por CG/EM foi observado rendimento 0,61 ± 0,07 (%) no óleo da dormência, quando comparado no período de brotação 0,55 ± 0,08 (%). Os bioensaios sobre as larvas e pupas de Aedes aegypti foram realizados pelo teste de imersão em diferentes concentrações dos OEs, que variaram de 500,00 a 0,003 mg mL-1 (v/v). Os resultados sobre as larvas e pupas indicaram uma CL99,9 de (0,01 e 1,38 mg mL-1) para o OE da dormência, e (0,08 e 2,63 mg mL-1) para o OE do período de brotação, respectivamente. Indicando maior atividade do OE da dormência. O mecanismo de ação dos OEs nos dois períodos foi determinado pelo método autobiográfico avaliando o potencial inibitório sobre a enzima acetilcolinesterase. Os resultados indicaram maior inibição da enzima do OE no período de dormência (0,039 mg mL-1), quando comparado ao OE de brotação (0,156 mg mL-1). A análise química destacou três compostos: epicurzerenone (18,20% e 12,10%) e 1,8 cineol (15,76% e 14,05%) e ß- elemeno (4,43 e 0,01%) em maior quantidade no período de dormência quando comparado ao período de brotação, respectivamente. Esta diferença pode explicar a maior ação inseticida do OE de dormência sobre as larvas e pupas do Ae. aegypti. Os resultados são promissores, pois estabelece em qual período do ciclo vegetativo o OE da C. zedoaria apresenta maior potencial bioinseticida.

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Local anaesthetics are among the most used drugs in clinical practice, but once they are released to the environment, the effects on the aquatic fauna remain uncertain. This study evaluates, for the first time, the impact of tetracaine, lidocaine and bupivacaine on the survival rate and physiological effects of cladocera Daphnia magna. Video-tracking and image processing allowed us to obtain changes in behaviour parameters like swimming average velocity and mean square displacement. We found that tetracaine shows the most severe effect. A high-speed microscopy system was also used to determine the response of D. magna heart to these drugs. Our results show that tetracaine presents dose-dependent area reduction during all cardiac cycle, while bupivacaine and lidocaine did not present significative effects on heart size. The tested drugs, at environmental high concentrations, altered behaviour, heart function and survival of D. magna.

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