Tetranychus urticae Koch is a cosmopolitan pest that causes damage to crops in protected farming activities in the semiarid region of the state of Pernambuco, Brazil. We investigated the lethal and sublethal effects of the essential oil from the latex of the mango fruit [Mangifera indica, Espada and Rosa (MESPA and MROSA) varieties] and selected monoterpenes on T. urticae. The yield of the MROSA oil was higher (9.22 ± 0.15%). The GC/MS analysis of the oils enabled the identification of 26 constituents. Terpinolene (70.14 ± 0.61%) was the major compound identified in the MESPA oil; β-pinene (38.22 ± 0.80%) was the major constituent of the MROSA oil, followed by terpinolene (29.44 ± 0.29%). The mite was more susceptible to the oils and constituents through fumigation, with no difference between the two varieties. By residual contact, the MROSA oil was 2.7-fold more toxic than the MESPA oil. Terpinolene was the most toxic constituent by fumigation, whereas β-pinene and α-pinene were the most active by residual contact. The selected compounds from M. indica also affected the behavior of the mite, exerting an influence on fecundity, feeding preference and egg-laying preference. The positive control (Azamax®) was more efficient at reducing the fecundity of the mite than the oils, but the MROSA oil was more toxic by fumigation and residual contact. The effects of fumigation and residual contact combined with the change in behavior may be a considerable advantage in the integrated management of T. urticae. For the practical use of these oils as novel acaricides, however, further investigations are needed to evaluate the effects on non-target organisms and the cost-benefit ratio for the formulation of a product to be used on protected crops in the semiarid region of the state of Pernambuco, Brazil.

Bemisia tabaci is a cosmopolitan pest responsible for causing harm to crops in the agricultural hub of Petrolina in the state of Pernambuco, Brazil. We investigated the lethal and sublethal effects of vapors from essential oils obtained through hydrodistillation of the peels of four species of Citrus and the latex from Mangifera indica (var. “rosa” and “espada”) on B. tabaci. The chemical analysis by Gas chromatography coupled to mass spectrometry of the oils led to the identification of 71 constituents, with limonene as the major component of the Citrus oils and terpinolene as the major component of the M. indica oils. B. tabaci was more susceptible to Citrus aurantiifolia (LC50 = 0.70 µL L-1 air) and C. limon (LC50 = 1.77 µL L-1 air) oils, which had the same level of toxicity. Citrus and M. indica oils also led to a reduction in the fecundity of the pest. The lethal and sublethal action of the constituents linalool, α-terpineol, α-pinene, β-pinene, terpinolene and limonene is also discussed. The toxicity of the oils investigated herein associated with the reduction in fecundity is a considerable advantage in the management of B. tabaci. However, for practical use of these oils as a novel insecticide to proceed, further research is required to address safety issues for human health and determine the formulation to improve the insecticidal potency, stability and cost-benefit ratio.

The fumigant action of peel essential oils of Citrus sinensis var. pear (pear orange = PO) and C. aurantium (bitter orange = BO) from the northeast of Brazil were evaluated against Bemisia tabaci biotype B and compared with eugenol as a positive control. The oil concentration in the PO at 8.5 μL/L of air caused 97% mortality, while the oil concentration of BO at 9.5 μL/L of air caused 99% mortality. However, the LC 50 estimates for both oils (LC 50 = 3.80 μL/L of air for PO and LC 50 = 5.80 μL/L of air for BO) did not differ from each other, but they did when compared with eugenol (LC 50 = 0.20 μL/L of air). Regarding their effects on oviposition, the Citrus oils showed concentration-response dependence, reducing the number of eggs as the concentration increased, which was not observed for eugenol. The minimum concentrations of the oils that caused a significant reduction in the egg lay were 3.5 and 7.0 μL/L of air for BO and PO, respectively. These results suggest that oils from PO and BO peels may be promising as models to develop new insecticides that might be applied into the integrated management of whiteflies.

A importância da Sequência Didática (SD) na matemática traz, através de atividades, uma avaliação formativa e regular do conhecimento construído e da formação do saber. O papel social de educar para a cidadania, a vida democrática e o ensino de Matemática não podem se restringir ao conhecimento dos conteúdos conceituais e procedimentais da área. Objetivou-se neste trabalho, elaborar e aplicar uma (SD) com atividades que contemplem conceitos de área e perímetro, interligando a aspectos geométricos para os alunos do PROEJA. A metodologia utilizada nessa pesquisa teve caráter de estudo exploratório, do tipo pesquisa-ação, com caráter descritivo, com oito estudantes do PROEJA do curso Técnico de Administração de uma Instituição pública, Campus Irecê, Rio Grande do Norte, dividida em três etapas: verificação diagnóstica, aplicação da SD e verificação de resultados. A SD composta pelos conceitos envolvendo Grandezas e Medidas, Números e Geometria, sendo estruturada para cinco dias discutindo atividades sobre Grandezas e Medidas no contexto diário, com aplicação de materiais manipulativos, que abordou a definição de figuras geométricas com foco nos conhecimentos de área e perímetro de figuras planas. Os resultados indicaram que a aplicação de atividades que priorizaram à construção do saber matemático com diferentes níveis hierárquicos de conceitos, priorizando a interação e a práticas com uso de instrumentos de medidas, a ludicidade e o dinamismo permitiu que a maioria dos alunos internalizasse os conceitos de área e perímetro. No entanto, duas alunas apresentaram dificuldades nas atividades por falta de interesse, desatenção ou desconhecimento, apresentando muita dificuldade na utilizar de instrumentos de medidas e conduzir o somatório para obtenção do perímetro. Conforme as observações levantadas, torna-se evidente que a SD foi um meio de estabelecer o vínculo da matemática com os estudantes da modalidade de Educação de Jovens e Adultos ao interligar conceitos de anos anteriores e proporcionar a compreensão da formação do saber. Consoante aos registros acompanhados, torna-se relevante conduzir estudos futuros de ampliação desta pesquisa para atingir novas habilidade da BNCC voltado ao ensino médio, em especial para a modalidade EJA.

No abstract