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RESUMO A tripanossomíase bovina é causada pelo protozoário Trypanosoma vivax. A transmissão biológica ocorre apenas no continente africano pela mosca Tsé-tsé, de forma mecânica por dípteros hematófagos em todos os continentes, ou pelo compartilhamento de agulhas e por práticas associadas. O estudo teve como objetivo relatar o primeiro diagnóstico parasitológico, sorológico e molecular de T. vivax em bovinos leiteiros provenientes de cinco propriedades do município de Unaí, Minas Gerais, Brasil. Cento e quinze animais selecionados por conveniência apresentavam sinais clínicos ou pertenciam a lotes de animais suspeitos. Foram detectados positivos pelos testes parasitológico (técnica de Woo), sorológico (ELISA) e molecular (LAMP). A maior prevalência global para T. vivax foi de 11,11% na propriedade A. O único sinal clínico dos animais positivos estudados foi baixa taxa de concepção. O primeiro diagnóstico de tripanossomíase no noroeste mineiro é extremamente importante, haja vista o tamanho do rebanho leiteiro da região e as possíveis perdas econômicas provocadas pela enfermidade. Ademais, faz-se necessário maior controle sanitário na região, uma vez que a transmissão no Brasil é intimamente ligada às práticas de compartilhamento de agulhas no manejo dos animais e ao parasitismo de moscas hematófagas.

This study aimed to compare the susceptibility of tomato pinworm, Tuta absoluta, from four Brazilian regions to insect growth disruptor (IGD) insecticides by tomato leaf-dip bioassays. Larval mortality was assessed seven days after exposure to insecticide-treated leaves. The control failure likelihood (CFL) was estimated after larval bioassays with IGDs recommended label rate. Mortality data were subjected to Probit and variance analysis. All populations of tomato pinworm showed significant resistance to one or more insecticides. The LC50 values ranged from 0.34 to 0.63 g L−1 (chlorfluazuron), 0.17 to 0.92 g L−1 (teflubenzuron), 0.13 to 1.28 g L−1 (novaluron), 0.29 to 0.46 g L−1 (lufenuron), and 0.71 to 4.60 g L−1 (methoxyfenozide). The resistance ratios varied from 1.2 to 1.8-fold (chlorfluazuron), 1.4 to 5.5-fold (teflubenzuron), 1.2 to 9.9-fold (novaluron), 1.0 to 1.6-fold (lufenuron), and 1.5 to 6.5-fold (methoxyfenozide). Despite the low resistance ratios ( 54%, indicating likely control failure at the IGD label rates. We detected significant variations among populations of T. absoluta for activity of enzymes glutathione S-transferases (GST), cytochrome P450-dependent monooxygenases (MFO) and α-esterase (EST), however there was no significant difference between the populations for activity of β-esterase (EST). The evolution of resistance in T. absoluta populations to IGDs observed in this study is likely due to high selection pressure, demanding insecticide resistance management practices and environmentally sustainable tactics to obtain a more effective control of this pest.

Competition with weeds and lack of selective herbicides registered for bird’s-foot trefoil crops affect their development and limit productivity. Therefore, this study aimed at evaluating selectivity of pre-emergent herbicides in bird’s-foot trefoil crops. Experiments were carried out in a greenhouse and on a field where the following herbicides were evaluated and compared with the control: imazethapyr, diclosulam, flumetsulam, metribuzin, s-metolachlor, sulfentrazone, clomazone and isoxaflutole. Regarding variables under evaluation, phytotoxicity (PHYTO), plant stature, dry mass of the aerial part (DMAP) and dry mass of roots (DMR) were evaluated in the greenhouse, while plant population, PHYTO and DMAP were assessed on the field. The criterion to determine selectivity were: PHYTO below 15% and not reducing the plant population nor morphological variables, by comparison with the control. The variables were negatively affected by the herbicides clomazone, metribuzin, isoxaflutole, diclosulam, s-metolachlor, in which the crop population was reduced in 98, 92, 83, 63, 48 and 22%, respectively. Following the criteria, only the herbicide sulfentrazone as a pre-emergente is selective to bird’s-foot trefoil crop (cultivar ‘Sao Gabriel’).

Multiferroic Ruddlesden-Popper Ca3Mn2O7 thin films were prepared by laser ablation on SrTiO3 substrates. For low laser fluences and high oxygen pressures, the films assumed the CaMnO3 Pnma orthorhombic structure. However, by increasing fluence and decreasing the oxygen pressure, the Ca3Mn2O7 phase is achieved through a post-deposition annealing treatment. Furthermore, the ferroelectric phase A21am was observed in the films, along with the orthorhombic Acaa phase, with a preferential [111] growth orientation and substrate-induced enhancement of the polar ferroelectric distortion. The dielectric permittivity shows dispersion described by the Havriliak-Negami function, and from fits to the curves, a different behavior was observed in the antiferromagnetic region. Also, the Kohlrausch-Williams-Watts stretched exponential parameter showed an abrupt decrease below ~110 K, near the Néel temperature. This indicates the presence of magnetoelectric interactions and magnetically induced enhancement of dipolar correlations in the samples, favoring substrate-induced strain to enhance multiferroicity in these films., This work was supported by the Portuguese Foundation for Science and Technology (FCT), through the projects POCI-01-0145- FEDER-029454, NORTE-01-0145-FEDER-028538, PTDC/NAN-MAT/ 0098/2020, NORTE-01-0145-FEDER-022096, and POCI-01-0145- FEDER-032527. V. B. Isfahani acknowledges a post-doc grant from the project NORTE-01-0145-FEDER-028538. B. M. Silva and J. Oliveira acknowledge their Ph.D. grants from FCT, with references 2021.07277. BD and SFRH/BD/146886/2019, respectively. F. L. Deepak acknowledges the CASOLEM project (028917) “Correlated Analysis of Inorganic Solar Cells in and outside an Electron Microscope”, co-funded by FCT and ERDF through COMPETE2020.

The production of systematic reviews and meta-analysis increased substantially. In this sense, we highlight those comparing Moderate-Intensity Continuous Training (MICT) and High-Intensity Interval Training (HIIT). It is known that meta-analyses of well-conducted studies are considered as a superior level of scientific evidence; therefore, it is relevant to critically analyze all those articles, especially speaking about the absence of differences between MICT and HIIT reported in previous studies. Widely, analyzing studies included in a meta-analysis frequently is possible to identify a lack of crucial information to the understanding of the exercise intervention, and this can skew readers interpretation and may conduct an equivocate comprehension of the results. In meta-analysis regarding the effects of MICT and HIIT in body composition, the relativization of the full length of training time of each intervention is frequently lacking. Data from previously published meta-analysis was reanalyzed, verifying higher relative reductions of body fat percentage to the HIIT group in comparison to the MICT group when considered the duration of interventions. In this sense, we suggest that all meta-analysis about this subject need not only to provide complete analysis in body composition but also consider analysis relativized of time spent training. Verifica-se substancial aumento na produção de revisões sistemáticas e metanálises, inclusive sobre os efeitos do exercício na composição corporal. Destacam-se aqui aqueles comparando Treinamento Contínuo de Intensidade Moderada (MICE) e Treinamento Intervalado de Alta Intensidade (HIIT). Observando que metanálises bem conduzidas apresentam maior nível de evidência científica, torna-se relevante analisar criticamente os trabalhos sobre a temática, a despeito da possível ausência de diferença entre MICE e HIIT previamente relatada. Isto deriva do impacto que protocolos e relatos adequados dos estudos primários exercem no resultado da metanálise. Ao analisar estudos incluídos em metanálises, são identificadas ausências de informações relevantes, o que enviesa a interpretação crítica do leitor, podendo conduzir à interpretação equivocada dos resultados. Observando metanálises sobre os efeitos do MICE e HIIT na composição corporal, questiona-se a carência de relativização do tempo total do treinamento para atingir os resultados. Ao reanalisarmos os dados de metanálise previamente publicada, verificamos maior redução relativa do percentual de gordura no grupo HIIT em comparação ao grupo MICE quando consideradas as durações das intervenções. À vista disto, indica-se que todas as metanálise acerca do tema deveriam concernir não somente análises absolutas da mudança de composição corporal, mas relativizá-las ao tempo treinado.

Among the species of the genus Cyperus occurring in paddy rice, C. esculentus, C. difformis and C. iria are the most important, and the latter two are reported as resistant to herbicides in Rio Grande do Sul (RS). The aim of this work was to characterize and mapping the occurrence of resistant plants of the genus Cyperus in areas of paddy rice in RS State, and to analyze the agronomic factors that interfere in the resistance selection. Seeds from individual plants were harvested in the 2014/15 crop, characterized as control failures by the application of acetolactate synthase inhibitors (ALS), totaling 43 samples. At the time of collection, the grower was inquired on aspects related to the management of weeds in the crop. Seeds were germinated in BOD and when seedlings were in two leaves stage they were transplanted into 0.3 L pots containing substrate. When the plants had 4-6 leaves, imazapyr + imazapic was spray at the registration rate. Thirty days after application, control of the tested biotypes was evaluated, converting the data to binary scale, where zero (0) and one (1) correspond to susceptibility and resistance, respectively. The agronomic factors that denote the high selection pressure of resistant biotypes are the consecutive use of Clearfield® technology, the use of higher doses than the registration and the low crop rotation adoption. Although not mentioned as one of the main weeds, it is observed that almost half of the samples collected from plants of the genus Cyperus are resistant to the ALS inhibitors, distributed in almost all the growing regions. RESUMO: Entre as espécies do gênero Cyperus ocorrentes na lavoura de arroz, destacam-se C. esculentus, C. difformis e C. iria, sendo as duas últimas relatadas como resistentes a herbicidas no Rio Grande do Sul (RS). Os objetivos deste trabalho foram caracterizar e mapear a ocorrência de plantas resistentes do gênero Cyperus em áreas de arroz irrigado no RS e analisar os fatores agronômicos que interferem na seleção da resistência. Foram realizadas coletas de sementes de plantas individuais na safra de 2014/15, caracterizadas como falhas de controle pela aplicação de inibidores da acetolactato sintase (ALS), totalizando 43 amostras. Por ocasião da coleta, o produtor foi arguido sobre aspectos relacionados ao manejo de plantas daninhas na lavoura. Na sequência, as sementes foram germinadas em BOD e, quando as plântulas estavam em estádio de até duas folhas, transplantadas para vasos com capacidade para 0.3 L contendo substrato. Quando as plantas apresentavam entre 4 e 6 folhas, foi aplicado imazapyr+imazapic na dose de registro. Aos 30 dias após a aplicação, foi avaliado controle dos biótipos testados, convertendo-se os dados em escala binária, em que zero (0) e um (1) correspondem a suscetibilidade e resistência, respectivamente. Os fatores agronômicos que denotam a alta pressão de seleção de biótipos resistentes são o uso consecutivo da tecnologia Clearfield®, o uso de doses superiores à de registro e a baixa adoção de rotação de culturas. Mesmo não sendo citada como uma das principais plantas daninhas, observa-se que quase a metade das amostras coletadas de plantas do gênero Cyperus são resistentes aos inibidores da ALS, distribuídas na quase totalidade das regiões de cultivo.

The tomato leafminer, Tuta absoluta (Meyrick), is one of the most important pests of tomato worldwide. The use of chemicals is still the major tactic of control against this pest in Brazil, where spray overuse leads to resistance, frequently associated with control failures in the field. In this study, a survey of the susceptibility to indoxacarb, metaflumizone, chlorfenapyr, cartap, and abamectin aimed to determine the resistance status of T. absoluta populations. Also, the major enzyme systems associated with metabolic resistance were assessed to infer variability. The LC50 values varied among the populations for abamectin (0.54–3.38 mg a.i./L), cartap (93.1–589.8 mg a.i./L), chlorfenapyr (0.62–2.83 mg a.i./L), indoxacarb (0.86–2.89 mg a.i./L), and metaflumizone (0.35–7.44 mg a.i./L). Resistance ratios varied among populations being 6.2-, 6.4-, 4.6-, 3.3-, and 21.2-times for abamectin, cartap, chlorfenapyr, indoxacarb, and metaflumizone, respectively. Only the cartap confidence limits of the LC80 bracketed the recommended label concentration for three populations (Anapolis, Guaraciaba do Norte, and Tiangua), suggesting control failures. No cross-resistance was observed between indoxacarb and metaflumizone, and natural variation may explain the variability of response to this latter insecticide. The activity of enzymes frequently associated with metabolism of insecticides significantly differed among populations, and glutathione S-transferases and cytochrome P450-dependent monooxygenases were variable among the populations of T. absoluta, while alpha and beta-esterases were very homogeneous. T. absoluta resistance to abamectin and cartap has not been critical in Brazil despite their long use and together with chlorfenapyr appear to be an interesting option of rotation with indoxacarb, for which there is no cross-resistance to metaflumizone.

Pneumonia is caused by microorganisms that settle in the lungs, which may reach the pulmonary alveoli and cause respiratory failure. Antibiotic treatments are the most used, although their use may not be efficient due to bacterial resistance. The antimicrobial peptide BP100 is a promising candidate for a new antibiotic due to its low susceptibility to bacterial resistance. It can be most effective when carried with gold nanoparticles (AuNPs) and polymer coatings for topical use. The goal of this work is to evaluate the effect of the transposition of the BP100 peptide carried on a gold nanoparticle coated with three types of polymers (polyethylene glycol (PEG), polystyrene (PS) and polyethylene glycol-block-polystyrene (PEG-b-PS)) using a lung surfactant (LS) model. The Gibbs free energies for nanoparticle transpositions are performed using coarse-grained molecular dynamics (CGMD) and umbrella sampling. The results demonstrate that the process is spontaneous for the BP100 adsorbed on the AuNPs encapsulated with PEG. The PEG effect on the AuNP-BP100-PEG system works as a protection method or a ligand competition for BP100 transposition. However, it is observed that the BP100-PEG nanoparticle breaks up as reaching the aqueous phase. Then, BP100 migrates to the polar heads region of the negatively charged phospholipids. It is possible to evaluate the effects of nanocarriers on the LS model. Besides that it is suggested the feasibility of applying antimicrobial peptides carried on PEG capped AuNPs for possible treatments of lung diseases.

Weeds emergence times modify competition with crops. Thus, the hypothesis was that the increase in weed emergence flow decreases the period prior to interference (PPI) in soybeans and increases the critical period of interference prevention (CPIP). The objective was to determine the PPI and the CPIP of weeds in soybean crops as affected by the preferred time of weeds emergence flow. Three experiments were conducted in the field in a randomized block design with four replications. The treatments were arranged in a factorial design with factor A consisting of coexistence or weed control in soybeans and factor B for eight periods (0, 7, 14, 21, 28, 35, 42 and 135 days after crop emergence (DAE)). The numbers of emerged plants and weed dry mass by genus and crop productivity were evaluated. The weed interference in culture during all the crop cycle reduces the soybean average yield 73, 94 and 89% in the first, second and third sowing times, respectively. Chemical control may be adopted at the end of PPI, which must be done at 14, 15 and 5 DAE crop, for the first, second, third times, respectively. The sowing in advance and intermediate time of recommendation increase the PPI in about 10 days, favoring the weed management in soybean crops. RESUMO: A época de emergência das plantas daninhas modifica a competição com as culturas. Assim, tem-se como hipótese que o aumento do fluxo de emergência de plantas daninhas diminui o período anterior à interferência (PAI) na soja, aumentando o período crítico de prevenção à interferência (PCPI). O objetivo foi determinar o PAI e o PCPI das plantas daninhas na cultura da soja, em função da época preferencial do fluxo de emergência de plantas daninhas. Realizaram-se três experimentos em campo, em delineamento experimental de blocos casualizados, com quatro repetições. Os tratamentos foram arranjados em esquema fatorial, sendo o fator A composto pela convivência ou controle de planta daninha na cultura da soja, e o fator B, por oito períodos (0, 7, 14, 21, 28, 35, 42 e 135 dias após a emergência da cultura -DAE). Avaliou-se o número de plantas emergidas e a massa seca das plantas daninhas por gênero, bem como a produtividade da cultura. A interferência das plantas daninhas na cultura durante todo o ciclo reduz a produtividade de soja, em média, em 73, 94 e 89% na primeira, segunda e terceira época de semeadura, respectivamente. O controle químico deve ser adotado ao final do PAI, o qual deve ser realizado aos 14, 15 e 5 DAE da cultura, para a primeira, segunda e terceira épocas, respectivamente. A semeadura realizada de forma antecipada e na época intermediária de recomendação aumenta o PAI em cerca de 10 dias, favorecendo o manejo das plantas daninhas na cultura da soja.

RESUMO - Populacoes de azevem resistente aos inibidores da enzima ALS tem aumentado rapidamente nos campos cultivados. Para o manejo da resistencia, sao necessarios estudos de heranca da resistencia, os quais permitem entender a evolucao da resistencia, a estrutura genetica da populacao e a dinâmica de adaptacao dos biotipos resistentes. Este trabalho teve como objetivo identificar o tipo de heranca, o numero de genes envolvidos e o grau de resistencia dos biotipos de azevem, homozigotos e heterozigotos, resistentes ao iodosulfuron. A partir da selecao dos biotipos homozigoto resistente (R) e homozigoto suscetivel (S), foram realizados cruzamentos (R x S) para obtencao de plantas F1, e estas, cruzadas para obtencao da F2, e realizaram-se retrocruzamentos entre plantas F1 e os respectivos genitores masculinos e femininos resistentes (RCr) e sensiveis (RCs). As sementes F1, F2, RCr, RCs e dos genitores foram semeadas em bandejas e avaliadas, com aplicacao do iodosulfuron, quanto a sua suscetibilidade ou resistencia. Plantas F1 e dos genitores foram tratadas com doses crescentes do herbicida. A avaliacao de controle dessas plantas pelo iodosulfuron foi feito por meio de notas (0 a 100), referentes aos sintomas de intoxicacao e pela massa da materia seca da parte aerea acumulada. Os genitores masculino ou feminino transmitiram a caracteristica para a prole, sendo esta 100% resistente, indicando gene de resistencia dominante. A geracao F2 apresentou segregacao 3:1 resistente/suscetivel, confirmando a caracteristica de dominância. O teste de dominância das plantas F1 evidenciou que as plantas homozigotas resistentes e as heterozigotas apresentam grau de resistencia semelhante. Conclui-se que a resistencia do azevem ao iodosulfuron e codificada por gene dominante nuclear com dominância completa. Palavras-chave: Lolium spp., genetica, herbicida.

Spinosad has been used to control Tuta absoluta in Brazil for more than a decade but will eventually be replaced by spinetoram despite the risk of cross-resistance. Therefore, the susceptibility to both molecules and the activity of detoxification enzymes were determined for eight representative populations of T. absoluta to assess resistance and the risk of cross-resistance. The LC50 values for spinosad varied from 0.007 (Pelotas) to 0.626 mg/L (Sumare); the LC50 values for spinetoram varied from 0.047 (Pelotas) to 0.308 mg/L (Sumare). The LC99 values for spinosad varied from 0.23 (Pelotas) to 11.56 mg/L (Venda Nova do Imigrante); the LC99 values for spinetoram varied from 0.55 (Pelotas) to 6.71 mg/L (Iraquara). The resistance levels ranged from 1.0- to 93.8-fold (RR50) and 1.0- to 51.5-fold (RR99) for spinosad and from 1.0- to 6.5-fold (RR50) and 1.0- to 12.1-fold (RR99) for spinetoram. The concentration-mortality responses to spinetoram were more homogeneous than those to spinosad. A strong correlation between the susceptibilities of T. absoluta populations to spinosad and spinetoram was observed, showing the similarity of the mode of action of both molecules and producing cross-resistance between them. The β–esterase activity of T. absoluta populations was correlated with spinosyn susceptibility, suggesting a potential contribution of the enzyme to evolved spinosyn resistance. The evolution of resistance to spinosyns in T. absoluta observed in this study suggests that strategies to mitigate resistance must be carefully implemented over the short term and that rotation with other products is encouraged.

BACKGROUND Phthalic and anthranilic diamides comprise a new insecticide class recently registered in Brazil to control Lepidoptera such as Tuta absoluta (Meyrick). Therefore, the baseline of susceptibility was determined for eight representative field populations of this species to establish a resistance monitoring programme. The potential for cross-resistance as well as detoxification metabolism was assessed in order to fine-tune the resistance management programme. RESULTS Brazilian populations were very susceptible to chlorantraniliprole (LC50 values varied from 3.17 to 29.64 µg AI L−1), cyantraniliprole (LC50 values varied from 8.61 to 28.95 µg AI L−1) and flubendiamide (LC50 values varied from 94 to 230 µg AI L−1), with respective resistance ratios of 9.33-, 3.36- and 2.45-fold between most susceptible and tolerant populations. Anthranilic diamides showed significant correlations between log LC50 values among themselves, suggesting a high risk of cross-resistance. However, the log LC50 values of T. absoluta to phthalic diamide did not show any correlation with anthranilic diamides. Cytochrome- P450-dependent monooxygenase activity showed a weak correlation with log LC50 values of T. absoluta populations to anthranilic diamides, which suggests a potential route for evolving resistance to anthranilic diamides. CONCLUSION The diamides were highly effective against T. absoluta, with populations showing a homogeneous response to them. Cross-resistance is very likely between anthranilic diamides in T. absoluta. Populations of this pest may evolve resistance by increasing cytochrome- P450-dependent monooxygenases. © 2014 Society of Chemical Industry

Chemical control with herbicides, especially glyphosate, is the main method used to control ryegrass. However, the repeated use of glyphosate has selected resistant ryegrass biotypes. Thus, the ACCase inhibitor herbicides have become the main alternative to control glyphosate-resistant biotypes, being widely used by farmers in Rio Grande do Sul. Repeated use of ACCase inhibitors, in turn, have selected ryegrass biotypes resistant to this herbicide mechanism. Thus, the objective of this study was to evaluate the response of ryegrass biotypes to different clethodim rates by dose-response curves. Increasing doses (0, 12, 24, 48, 72, 96, 144 and 192 g a.i. ha-1) of the herbicide clethodim were applied at the 3-4 ryegrass leaf stage. The variables control at 14 and 28 days after treatment (DAT) and shoot dry weight were evaluated. The data were fitted by nonlinear regression log-logistic and C50 and GR50 were calculated based on the equation. The resistance factor was obtained by the ratio of C50 or GR50 of the resistant biotype by matching the susceptible biotype. Based on the equation parameters, the doses of GR50 64.7 and 234.5 g a.i. ha-1 clethodim and C50 11.2 and 172.1 g a.i. ha-1 clethodim were obtained, at 28 DAT for the susceptible and resistant biotypes, respectively. The ryegrass biotype denominated Cotril is resistant to clethodim, being controlled with a dose 15.3 times greater than that of the susceptible biotype, and a 50% reduction of this biotype occurs with a dose 3.62 times higher than that of the susceptible one.

Chlorantraniliprole, a new anthranilic diamide, is an insecticide that has recently been registered in Brazil to control several lepidopterans, including the diamondback moth, Plutella xylostella (L.). Chemical control of this pest has been particularly difficult because of its evolution of resistance to previous insecticide classes. To deploy a chlorantraniliprole resistance-monitoring program, the susceptibility of P. xylostella populations from different regions of Brazil was assessed using concentration-mortality bioassays before the commercial release of chlorantraniliprole. Mortality data were subjected to Probit analysis to estimate lethal parameters. Dosing by immersion or by spraying in a Potter tower were both suitable but topical application was not. All of the P. xylostella populations were highly susceptible to chlorantraniliprole (LC 50 0.015–0.056 mg a.i./l of water) with those from the Northeast being the most tolerant. LC 99 values were also low (0.065–0.281 mg a.i./l). The susceptibility variation among the populations was notably low, with the highest tolerance ratio being 3.8 fold, indicating a low variability of response among the Brazilian populations to this insecticide. A discriminating concentration of 0.3 mg a.i./l was obtained from the baseline data and proved to be effective for evaluating other populations, causing 100% mortality. The baseline data reflect the natural variation of these P. xylostella populations to chlorantraniliprole, rather than variations caused by previous exposure.

The cotton leaf worm, Alabama argillacea , is a key cotton pest in Brazil and is managed with repeated insecticide applications. Reports of insecticide control failures have recently increased, particularly with pyrethroids. The present work assessed the resistance status of A. argillacea to a number of different insecticides currently used in cotton crops. Bioassays were conducted to estimate the response of 2nd-instar A. argillacea populations to deltamethrin, chlorpyrifos, endosulfan, abamectin and spinosad. A leaf dip bioassay with diluted insecticide formulations was performed in the laboratory with five to nine populations depending on the insecticide. LC 50 values were estimated by probit analysis after correction for control mortality data and used to calculate the resistance ratios (RR). All assessed populations exhibited varied and significant levels of resistance to all insecticides tested, but only moderate levels of resistance to deltamethrin were observed (RR = 52.3). The LC 50 values for deltamethrin were higher than 30 mg/l for most populations, and above the field rate (12.5 mg/l). This suggests that the frequency of resistant individuals in these populations was likely above the critical frequency. There was low to moderate resistance to abamectin, chlorpyrifos, endosulfan and spinosad formulations (the highest RRs observed were 4.2, 8.4, 11.1 and 23.5, respectively). Despite the moderate levels of resistance to pyrethroids in A. argillacea , overall results indicate the presence of low to moderate resistance of A. argillacea to insecticides currently used against cotton pests in Brazil.

The introduction of an agricultural pest species into a new environment is a potential threat to agroecosystems of the invaded area. The phytosanitary concern is even greater if the introduced pest's phenotype expresses traits that will impair the management of that species. The invasive tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one such species and the characterization of the insecticide resistance prevailing in the area of origin is important to guide management efforts in new areas of introduction. The spinosad is one the main insecticides currently used in Brazil for control of the tomato borer; Brazil is the likely source of the introduction of the tomato borer into Europe. For this reason, spinosad resistance in Brazilian populations of this species was characterized. Spinosad resistance has been reported in Brazilian field populations of this pest species, and one resistant population that was used in this study was subjected to an additional seven generations of selection for spinosad resistance reaching levels over 180,000-fold. Inheritance studies indicated that spinosad resistance is monogenic, incompletely recessive and autosomal with high heritability (h(2) = 0.71). Spinosad resistance was unstable without selection pressure with a negative rate of change in the resistance level ( = -0.51) indicating an associated adaptive cost. Esterases and cytochrome P450-dependent monooxygenases titration decreased with spinosad selection, indicating that these detoxification enzymes are not the underlying resistance mechanism. Furthermore, the cross-resistance spectrum was restricted to the insecticide spinetoram, another spinosyn, suggesting that altered target site may be the mechanism involved. Therefore, the suspension of spinosyn use against the tomato borer would be a useful component in spinosad resistance management for this species. Spinosad use against this species in introduced areas should be carefully monitored to prevent rapid selection of high levels of resistance and the potential for its spread to new areas.

The Relative Dose Response Test (RDR) was used to assess the bioavailability of vitamin A in a stabilized form in artificially produced rice kernels. The vitamin A proved stable to storage and cooking, and the enriched rice was nontoxic, and had the same sensory characteristics of ordinary rice. The nutrified rice, cooked with sugar and milk, was offered to 83 deprived children as the challenge dose for an RDR test. The children showed positive and negative tests in agreement with their serum retinol levels. The regression of RDR on serum retinol levels was the same as that observed when the conventional RDR test was applied.