Population dynamics and infestation of Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) in dwarf cashew genotypes.

The objective of this study was to evaluate the Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) population dynamics and to identify dwarf cashew genotypes less infested by the pest in 2015 and 2016, under field conditions. H. fulvus population evaluations were carried out by monthly observations in the plants and using a score scale varying from 0 to 4. H. fulvus infestation occurred from October to December, and in the cashew genotypes CAP 112/8, CAP 121/1, CAP 131/2, CAP 145/2, CAP 145/7, CAP 128/2, CAP 120/4, CAP 123/6, CAP 130/1, and CAP 157/2 was dependent on the flowering period of the crop in 2015. In 2016, there was dependence in all evaluated genotypes between H. fulvus infestation and the cashew flowering period. In 2015, no significant differences were observed between the evaluated genotypes regarding H. fulvus infestation. In 2016, genotypes CAP 105/5, CAP 143/7, CAP 150/3, CAP 155/2, CAP 158/8, CAP 161/7, CAP 163/8, CAP 31, CAP 71, CAP 92, CAP 113, CAP 120, CAP 155, CAP 165, CAP 106/1, CAP 111/2, CAP 127/3, CAP 157/2, and BRS 226 were less infested. H. fulvus occurs from October to December and we could identify the dwarf cashew genotypes less infested by the pest.

Atividade larvicida de óleos essenciais contra Aedes aegypti L. (Diptera: Culicidae) / Larvicidal activity of essential oils against Aedes aegypti L. (Diptera: Culicidae)

Na busca por controle químico alternativo contra Aedes aegypti L., muitas pesquisas são desenvolvidas e estimuladas no intuito de se descobrirem novas substâncias inseticidas de origem vegetal. Neste trabalho, o efeito larvicida de dez óleos essenciais foi avaliado contra A. aegypti. Os óleos foram obtidos por arraste a vapor e sua composição química foi determinada por cromatografia gasosa acoplada a espectrometria de massa. Os óleos essenciais foram diluídos em solução aquosa de dimetil sufóxido nas concentrações: 100, 50, 10 e 1 mg/ml. A atividade larvicida, baseada na percentagem de larvas mortas, foi avaliada 24h após o tratamento. O óleo essencial de Vanillosmopsis arborea Baker induziu a maior atividade larvicida, com CL50 de 15,9 mg/ml e CL90 de 28,5 mg/ml., enquanto o de O. gratissimum L. apresentou a menor atividade com CL50 de 95,80 mg/ml e CL90 de 102,86 mg/ml. Os resultados indicam que os óleos essenciais avaliados, principalmente o de V. arborea, são compostos por substâncias com efeito larvicida contra A. aegypti.

In the search for alternative chemical control against Aedes aegypti L., many researches are developed and encouraged in order to find new insecticidal plant substances. In this work, the larvicidal effect of ten essential oils was tested on A. aegypti. The oils were extracted by steam distillation and their chemical composition determined by GL-chromatography coupled with massspectroscopy. The essential oils were diluted in aqueous solutions of dimethyl sulfoxide with concentrations of: 100, 50, 10, and 1 mg/ml. The larvicidal activity, based on the percentage oflarval mortality, was evaluated after 24h exposure to the treatments. The essential oil of Vanillosmopsis arborea Baker presented the highest larvicidal activity, with CL50 of 15.9 mg/ml and CL90 of 28.5 mg/ml. On the other hand the essential oil of O. gratissimum L. showed the lower activity with CL50de 95,80 mg/ml and CL90 de 102,86 mg/ml. The results indicate that the tested essential oils, and particularly the V. arborea, are composed by substances with larvicidal properties for A. aegypti.