Ação inseticida do extrato de Derris amazonica Killip para Cerotoma arcuatus Olivier (Coleoptera: Chrysomelidae

A abundância e o potencial inseticida de Derris amazonica e a necessidade de controle de Cerotoma arcuatus Olivier (Coleoptera: Chrysomelidae) na cultura do feijão-caupi (Vigna unguiculata L. Walp) estimularam a realização desta pesquisa, que objetivou avaliar a ação inseticida do extrato de D. amazonica a adultos de C. arcuatus em condições de laboratório. Os bioensaios testaram as vias de intoxicação por ingestão de folhas contaminadas, contato com superfície contaminada e aplicação tópica, com delineamento experimental inteiramente casualizado, com quatro repetições. Os valores de mortalidade e consumo foliar dos insetos foram submetidos à análise de regressão, sendo utilizada a análise de Probit para determinação das CL50, da DL50 e dos TL50. O extrato de D. amazonica, contendo 3,7% de rotenona, foi tóxico para adultos de C. arcuatus via ingestão de folhas contaminadas (CL50=15,14 µL do extrato.mL-1 de água), superfície contaminada (CL50=0,45 µL do extrato.cm-2) e aplicação tópica (DL50=1,44 µL do extrato.g-1 do inseto). Mortalidades de adultos de C. arcuatus superiores a 80% e os menores tempos letais médios foram obtidos na concentração de 5% (v v-1) do extrato em todos os bioensaios. O consumo foliar de adultos de C. arcuatus foi inversamente proporcional a concentração do extrato quando expostos por via de ingestão foliar ou aplicação tópica, sendo inclusive observada inibição da alimentação dos indivíduos. O extrato de D. amazonica é tóxico para C. arcuatus e inibe a alimentação dos insetos a partir da concentração de 1% (v v-1).The abundance and insecticidal potential of Derris amazonica in addition to need of controlling Cerotoma arcuatus for bean crop stimulated this research. The objective of this work was to evaluate insecticide action of the extract of D. amazonica to adults of C. arcuatus in laboratory conditions. The bioassays were carried out using three distend methodologies: leaf intake, contact in treated surface (filter paper) and topical application. A completed randomized experimental design was used with four replications. Mortality values and leaf consumption of the insects were subjected to regression analyses, being the Probit analyses used to determine of the i.e., LC50, LT50 and LD50. The extract of D. amazonica containing 3.7% of rotenone was toxic to adults C. arcuatus when exposed to treated leaves (LC50 = 15.14 µl.mL-1), treated surface (LC50 = 0.45 µl.cm-2) and subjected to topical exposure (LD50 = 1.44 µl.g-1). In all bioassays the adults mortality was higher than 80% with lower median lethal times obtained with 5% (v.v-1) concentrations of the extract. Leaf consumption by adults C. arcuatus was inversely proportional to the concentration of the extract when exposed by leaf intake or topical application, also being observed inhibition of feeding individuals. The extract of D. amazonica is toxic to C. arcuatus and inhibits the feeding of insects from the concentration of 1% (v v-1)

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A new three-degrees-of-freedom (3-DOF) translational parallel manipulator (TPM) with linear actuators, i.e., 3-CRR TPM, is first proposed. The rotation singularity analysis, the inverse kinematics, the forward kinematics, and the kinematic singularity analysis of the 3-CRR TPM are then performed. The analysis shows that the proposed TPM has the following kinematic merits over previous TPMs. (1) The forward displacement analysis can be performed by solving a set of linear equations. (2) The Jacobian matrix of the TPM is constant. The inverse of the Jacobian matrix can be pre-calculated, and there is no need to calculate repeatedly the inverse of the Jacobian matrix in performing the forward displacement analysis and forward velocity analysis. (3) There is no rotation singularity. (4) There is no uncertainty singularity. (5) The TPM has a fewer number of links or joints. The geometric condition for a 3-CRR TPM to be isotropic i

Generation of Architecturally Singular 6-SPS Parallel Manipulators with Linearly Related Planar Platforms

An architecturally singular parallel manipulator is a parallel manipulator with architectural singularities spanning the whole workspace. It should be abandoned in the design process. This paper deals with the generation of architecturally singular 6-SPS parallel manipulators with linearly related planar platforms. The forward displacement analysis of the 6-SPS parallel manipulator with linearly related planar platforms is performed at first. All the architecturally singular 6-SPS parallel manipulators with linearly related planar platforms are then generated. It is found that a 6-SPS parallel manipulator with linearly related planar platforms is architecturally singular if and only if all the spherical joints on the base (or moving platform ) are located on a conic section. At last, self-motion analysis of the architecturally singular 6-SPS parallel manipulators with linearly related planar platforms is addressed