ABSTRACT
The objective of this study was to evaluate the mortality of Aphis craccivora Koch (Hemiptera: Aphididae) submitted to different extracts with different concentrations of leaves of the native forest species: Tetragastris altissima (Aubl.) Swart (Burseraceae), Metrodorea flavida K. Krause (Rutaceae) and Cheiloclinium cognatum (Miers) AC Sm (Celastraceae) under laboratory conditions. Adults of Aphis craccivora were collected in Gliricidia sepium (Jacq.) Kunthe Walp. (Fabaceae), and separated into groups of ten individuals, transferred to Petri dishes and exposed to topical application of aqueous, alcoholic and leaf infusion extracts of Cheiloclinium cognatum, Metrodorea flavida and Tetragastris altissima. The extracts were applied at concentrations of: 3, 6, 9, 12 and 15%, with 1% dimethylsulfoxide (DMSO), using a control treatment 1 (distilled water + DMSO 1%) and control treatment 2 (fipronil). Evaluations were performed at 24, 48 and 72 hours after the application of the extracts by counting the dead insects. The experimental design was completely randomized, with five replicates, three types of extracts and five concentrations with controls. In all the studied species, the aqueous and infusion extracts presented a lower mortality (less than 52%), whereas the alcoholic extract in higher concentrations of Cheiloclinium cognatum, Metrodorea flavida showed a mortality of up to 100%. The species Tetragastris altissima reached an average mortality of 92%. The lethal concentration for the alcoholic extract of Cheiloclinium cognatum was LC50 6.43% and LC90 12.22%, Metrodorea flavida LC50 was 3.08% and LC90 7.05% and that for Tetragastris altissima LC50 5.58% and LC90 17.47%, after 72 hours. The use of the alcoholic extract of the species Metrodorea flavida at a concentration of 9% in the control of Aphis craccivora is indicated.
Subject(s)
Aphids/drug effects , Plant Extracts/chemistry , InsecticidesABSTRACT
Bark beetles (Curculionidae: Scolytinae) are wood borers with the potential to cause significant damage in forest plantations. Studies of this group are more common in plantations of Eucalyptus, and Pinus, but the increase of planting with other forest species, such as Brazil nut and rubber trees, indicates the need for monitoring of Scolytinae in these additional forest areas. Thus, the objective of this work was to evaluate an assemblage and the main species of bark beetles in a mixed plantation of Brazil nut trees (Bertholletia excelsa Bonpl.) and rubber trees (Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg.) in Southern Amazonia. Twelve ethanol traps were used and collections were carried out biweekly for one year. The collections were evaluated descriptively way with entomofaunistic analysis, and population fluctuation and its dispersion were determined. A total of 2,738 individuals were collected, with a total of 17 species distributed in nine genera, of which Cryptocarenus Eggers 1937 and Xyleborus Eichoff 1864 showed the greatest representation. Cryptocarenus diadematus Eggers, Cryptocarenus heveae (Hagedorni), Cryptocarenus seriatusEggers, Xyleborus affinis Eichhoff, and Xyleborus spinulosus Blandford were categorized as dominant, very abundant, very frequent, and constant. The assemblage of Scolytinae in the Brazil nut tree and rubber tree mixed plantation had a greater abundance in the rainy season, with the highest averages and population peaks. The species with the greatest representation also presented a greater number of individuals in the rainy season with aggregate dispersion.
Scolytinae são coleobrocas com potencial de causar significativos danos em plantios florestais. Estudos com este grupo são mais comuns em plantios de Eucalyptus e Pinus, mas o aumento das áreas de plantio com outras espécies florestais como castanheira e seringueira indica a necessidade demonitoramento também dos Scolytinae nestas áreas florestais. Assim, o objetivo deste trabalho foi avaliar uma assembléia e as principais espécies coletadas de escolitíneos (Curculionidae: Scolytinae) em um plantio misto de castanheira (Bertholletia excelsa Bonpl.) e seringueira (Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg.) na Amazônia Meridional, no município de Alta Floresta, Mato Grosso. As coletas foram realizadas quinzenalmente no período de agosto de 2015 a agosto de 2016, em 12 armadilhas de etanol. A assembléia foi avaliada de maneira descritiva com análises entomofaunisticas, e para as principais espécies determinou-se sua flutuação populacional e dispersão. Um total de 2.738 indivíduos foram coletados, totalizando 17 espécies distribuídas em nove gêneros, dos quais Cryptocarenus Eggers 1937 e Xyleborus Eichoff 1864foram os mais representativos. Na análise entomofaunística, Cryptocarenus diadematus Eggers, Cryptocarenus heveae(Hagedorni), Cryptocarenus seriatus Eggers, Xyleborus affinis Eichhoff e Xyleborus spinulosus Blandford foram dominantes, muito abundantes, muito frequentes e constantes. A assembléia de Scolytinae no plantio misto de castanheira com seringueira, apresentou maior abundância na estação chuvosa, com as maiores médias e picos populacionais. E as principais espécies coletadas também apresentaram maior número de indivíduos coletados na estação chuvosa com dispersão agregada.
Subject(s)
Forests , Hevea , Bertholletia , EntomologyABSTRACT
Currently, few active principles are authorized by the forest certification for the control of insect pests, with which it is necessary to develop new products, mainly aiming at lower environmental impact. The plants are able to develop substances called secondary metabolites, widely studied as an alternative form of pest control. Thus, the objective of this study was to evaluate the insecticidal potential of two Musa acuminata extracts, on the control of Atta sexdens rubropilosa. The extracts were obtained from the pseudostem of M. acuminata, which underwent drying and milling, producing two extracts: ethanolic (A1) and hydroethanolic rotaevaporate (A2) extract. For the analysis of the bioactivity of the extracts, a topical application of one milliliter of each extract on the ants was carried out, with the aid of spray, in the concentrations of: 2, 6, 10, 14, 18, and 20%, with distilled water (witness) applied to the test, analyzing the mortality and LC50, in different evaluation periods. At 24 hours the mortality of 90% at the concentration of 20% for the A1 extract was observed. From the 10% concentration there was 100% mortality in this same period for the A2 extract, and at 48 hours the 2% concentration caused 100% mortality. In the LC50 analysis for 24 hours values of 7.94 and 1.09% were obtained for ethanolic extract and rotavaporated ethanolic extract respectively. And the LC50 presented a decrease in values after 48 hours for the ethanolic extract presented value of 2.29%. Thus, it can be concluded that the A2 extract is the most efficient, since it allows the lower consumption of extract in the dilution for later application, due to the presence of insecticidal potential in low concentration.
Atualmente, poucos princípios ativos são autorizados pela certificação florestal para o controle de insetos-praga, sendo necessário desenvolver novos produtos, principalmente visando menor impacto ambiental. As plantas são capazes de desenvolver substâncias chamadas metabólitos secundários,amplamente estudadas como uma forma alternativa de controle de pragas. Assim, o objetivo deste trabalho foi avaliar o potencial inseticida de dois extratos de Musa acuminata, no controle de Atta sexdens rubropilosa. Os extratos foram obtidos a partir do pseudocaule de M. acuminata, que foi submetido a secagem e moagem, produzindo dois extratos: etanólico (A1) e hidroalcoólico rotaevaporado (A2). Para a análise da bioatividade dos extratos, foi realizada uma aplicação tópica de um mililitro de cada extrato sobre as formigas, com o auxílio de spray, nas concentrações de: 2, 6, 10, 14, 18 e 20%, com água destilada (testemunha) aplicada ao teste, verificando-se a mortalidade e a CL50, em diferentes períodos de avaliação. Às 24 horas foi observada mortalidade de 90% na concentração de 20% para o extrato A1. A partir da concentração de 10% houve 100% de mortalidade nesse mesmo período para o extrato A2, e às 48 horas a concentração de 2% causou 100% de mortalidade. Na análise da LC50 para 24 horas obteve-se valores de 7,94 e 1,09% para o extrato etanólico e o extrato rotaevaporado respectivamente. E a CL50 apresentou diminuição nos valores apartir das 48 horas para o extrato etanólico apresentando valor de 2,29%. Assim, pode-se concluir que o extrato A2 é o mais eficiente, pois permite o menor consumo de extrato na diluição para posterior aplicação, devido à presença de potencial inseticida em baixa concentração.
Subject(s)
Solid Waste , Forestry , Entomology , InsecticidesABSTRACT
Este trabalho objetivou relatar o ataque de lagartas desfolhadoras de eucalipto no Estado do Rio Grande do Sul. A espécie foi determinada como sendo Nystalea nyseus (CRAMER, 1775) (Lepidoptera: Notodontidae). As lagartas dessa espécie causam desfolhamento em árvores de eucalipto. Este é o primeiro registro de Nystalea nyseus em árvores de eucalipto no Estado.
This research aimed to record the damage caused by Eucalyptus-defoliating caterpillars located in Rio Grande do Sul States, Brazil. The specie was determined as Nystalea nyseus (CRAMER, 1775) (Lepidoptera: Notodontidae). The caterpillars of this species cause defoliation in Eucalyptus trees. This is the first record of Nystalea nyseus from Eucalyptus plantation in the Rio Grande do Sul State, Brazil.
ABSTRACT
Esta nota tem por objetivo relatar o ataque de larvas do coró-das-pastagens, Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae), em mudas de eucalipto híbrido (Eucalyptus grandis x Eucalyptus urophylla), na fazenda Bazana, município de Manoel Viana, Rio Grande do Sul. Essa praga se alimentou da casca das plantas na região do coleto, provocando anelamento das mudas. A mortalidade de mudas foi de 30 por cento em 40ha. Este é o primeiro registro dos danos desse inseto em plantas de eucalipto no Brasil.
This article aims to report the attack of larvae Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae) on seedlings of Eucalyptus hybrid ( Eucalyptus grandis x Eucalyptus urophylla), on the farm Bazana, in Manoel Viana, state of Rio Grande do Sul, Brazil. This pest consumed the bark of the ground, which caused the 'girdling' of seedlings. The mortality rate was 30 percent, in 40ha. No previous report was found in the literature regarding the occurrence of damages of Diloboderus abderus on Eucalyptus; thus, this is the first record of the pest on Eucalyptus in Brazil.