Cerambycidae associated with hybrid Eucalyptus urograndis and native vegetation in carbonita, Minas Gerais state, Brazil

Wood-borers of exotic and native trees are important pests of eucalyptus in many regions of the world. The feeding behavior of these insects causes losses in wood production. The aim of this study was to identify Cerambycidae beetles inhabiting plantations of clonal hybrid (Eucalyptus grandis × E. urophylla hybrid; Myrtales: Myrtaceae) and native cerrado vegetation in order to improve knowledge about potential wood-borers in these habitats. The insects were collected weekly using baited traps located within eucalyptus stands and in the cerrado vegetation. In total, 3,377 individuals belonging to 13 cerambycid species were caught. The potential wood-borers species in eucalyptus managed plantations should to be monitored during the rainy period.Besouros broqueadores exóticos e nativos de espécies florestais são pragas importantes do eucalipto em várias regiões do mundo. O hábito alimentar destes insetos causa perdas na produção de madeira. O objetivo deste estudo foi identificar espécies de Cerambycidae em plantio de híbrido clonal (Eucalyptus grandis × E. urophylla hybrid; Myrtales: Myrtaceae) e em área de Cerrado nativo para se identificar broqueadores dessas plantas. Os insetos foram coletados, semanalmente, com armadilhas iscadas em talhões de eucalipto e na área de Cerrado nativo. Um total de 3.377 indivíduos de 13 espécies de cerambicídeos foi coletada. Besouros broqueadores em plantios de eucalipto devem ser monitorados, especialmente, em períodos chuvosos

Eucalyptus seedlings quality treated with pyroligneous extract

Bioassays were made in field conditions, in Olhos D Água, Minas Gerais, Brazil, for evaluating pyroligneous extract action on seedlings of Eucalyptus grandis x Eucalyptus urophylla clones treated by irrigation. Seedlings 45 days old received the fertilization concentrated and the pyroligneous extract at different concentrations during 45 days, three applications per week. It was evaluated the height, the diameter, the dry mass of the aerial part of trees (DMA), the dry mass of the root (DMR) and the potential of root growth (PRG) of the seedlings. Pyroligneous extract (from 0.0 to 2.0%) did not promote additive effects on eucalyptus seedlings of E. grandis x E. urophylla clones. The increasing of the pyroligneous extract concentration reduced the diameter, DMA and DMR of eucalyptus seedlings. Application of 100% of the recommended rate of fertilizer produced higher height, dry mass of the aerial part of tree, dry mass of the root and potential of root growth of the seedlings of E. grandis x E. urophylla clones, than with 50%.Bioensaios foram realizados em condições de campo, em Olhos D Água, Minas Gerais, Brasil, para avaliar a ação do extrato pirolenhoso sobre mudas de clone de híbrido de Eucalyptus grandis x Eucalyptus urophylla tratadas via irrigação. Mudas com idade de 45 dias receberam adubação concentrada e extrato pirolenhoso em diferentes concentrações durante 45 dias, com uma freqüência de três aplicações/semana. Foram avaliados a altura, o diâmetro do colo, a massa seca da parte aérea (MSPA), a massa seca radicial (MSR) e o potencial de crescimento radicial (PCR) das mudas. O extrato pirolenhoso nas concentrações de 0 a 2,0% não contribui para a melhoria da qualidade das mudas de clone de híbrido de E. grandis x E. urophylla. O aumento da concentração do extrato pirolenhoso diminui o diâmetro, a MSPA e a MSR das mudas de clone de híbrido de E. grandis x E. urophylla. A aplicação de 100% da adubação de crescimento causa maior altura, MSPA, MSR e PCR de mudas de clone de híbrido de E. grandis x E. urophylla em comparação com a de 50%

Damage by Acromyrmex spp. to an Initial Pinus taeda L. Planting

The objective of this study is to evaluate the damage caused by Acromyrmex heyeri Forel, 1899 and Acromyrmex lobicornis Emery, 1887 to Pinus taeda L. seedlings during the first two months after replanting. The experiment was conducted in the company Bosques del Plata, located in the province of Corrientes, Argentina. The evaluations were carried out at seven, 14, 21, 36, 50 and 65 days after replanting the seedlings, when the number of dead, alive, non-attacked, alive deneedled, and alive deneedled with cuts/damage to the apical bud by leaf-cutting ants was quantified. The results allow us to conclude that A. heyeri and A. lobicornis are responsible for losses to the order of 20.8% of the seedlings in an initial P. taeda stand at 65 days. The damage caused to seedlings by the two leaf-cutting ant species is constant over time, in which A. lobicornis is more voracious than A. heyeri

Mechanized systematic application of granuleted ants baits in eucalyptus plantations in maintenance phase

Compared to manual control, systematic control WITH ant bait requires less labor, results in lower exposure of workers and increases operating YIELD. This study aimed to evaluate the mortality of leaf-cutting ants nests with a mechanized systematic application of ant bait in three spacings on eucalyptus plantations in maintenance phase, the operational capability of mechanized application and the quality of the distribution of bait throughout the area. The experiment was conducted in the city of Paropeba, Minas Gerais, Brazil, in stands of eucalyptus plantations in maintenance phase. A sulfluramid (0.3%) based bait was systematically applied at 1 kg.ha-1 every 6 x 2.5 9 x 2.5 and 12 x 2.5 meters, with an application equipment attached to the hydraulic system of a tractor, comprising three  treatments with five repetitions. Nests with a size of up to one square meter of land area were selected and marked and evaluated their inactivity at 60 and 210 days after bait application. The percentage of bait loading, the operational capability of the mechanized process and the quality of the distribution process of the bait were also evaluated, using control charts. It was found that the different spacings applied did not influence the effectiveness of control. The largest spacing used provided greater operational capacity (8.42 ha.h-1). The mechanized systematic application provided good distribution as to the process’ statistical control, being a viable alternative to manual application.O controle sistemático mecanizado com isca formicida em eucaliptais demanda menos mão de obra, menor contaminação dos trabalhadores e maior rendimento operacional, quando comparado com o controle manual. O objetivo deste trabalho foi avaliar a mortalidade de ninhos de formigas cortadeiras com aplicação sistemática mecanizada de isca formicida em três espaçamentos em eucaliptais em fase de manutenção, a capacidade operacional da aplicação mecanizada e a qualidade de distribuição de isca ao longo da área. O experimento foi realizado no município de Paraopeba, Minas Gerais, em talhões de eucaliptos em fase de manutenção. Foi aplicado 1 kg.ha-1 de isca formicida granulada a base de sulfluramida (0,3%) sistematicamente a cada 6 x 2,5 m, 9 x 2,5 m e 12 x 2,5 m, com um equipamento de aplicação acoplado ao sistema hidráulico de um trator, constituindo três tratamentos com cinco repetições. Foram selecionados e marcados ninhos com tamanho de até um metro quadrado de área de terra e avaliado sua inatividade aos 60 e 210 dias após aplicação da isca formicida. Também foram avaliadas a percentagem de carregamento da isca, a capacidade operacional da operação mecanizada e a qualidade do processo de distribuição da isca, por meio de cartas de controle. Verificou-se que os diferentes espaçamentos empregados não influenciaram a eficácia de controle. O maior espaçamento empregado proporcionou maior capacidade operacional (8,42 ha.h-1). A aplicação sistemática mecanizada proporcionou boa qualidade de distribuição, sob ponto de vista do controle estatístico de processo, constituindo alternativa viável a aplicação manual

Atividade inseticida de extratos de plantas no controle de formiga cortadeira, em cafeeiro

The objective of this work was to evaluate the efficiency of extracts of plants from Minas Gerais in the control of leaf cutting ant Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). Seventy plant extracts were evaluated, being applied to the diet of the test insects. It was verified that only the botanical extracts Eugenia florida and Eugenia handroana (Myrtaceae), Trichilia pallida (Meliaceae) and Zanthoxylum pohlianum (Rutaceae) present lethal effect, with mortality average of 16.7; 23.3; 19.7 and 17.3%, respectively.Objetivou-se, neste trabalho, avaliar a eficiência de extratos de plantas, coletadas em municípios do estado de Minas Gerais, no controle de formiga cortadeira Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae), em condições de laboratório. Realizaram-se bioensaios em que foi avaliado o efeito formicida de 70 extratos de plantas, fornecidos aos insetos via ingestão de dieta contaminada. Constatou-se que apenas os extratos botânicos das espécies Eugenia florida e Eugenia handroana (Myrtaceae), Trichilia pallida (Meliaceae) e Zanthoxylum pohlianum (Rutaceae) reduziram a sobrevivência dos insetos, com mortalidade média de 16,7; 23,3; 19,7 e 17,3%, respectivamente

Toxicity of alkaloid fractions from Psychotria spp. (Rubiaceae) against Atta Sexdens Forel, 1908 (Hymenoptera: formicidae)

Leaf-cutting ants are the main pests in forest plantations. The most commonly used chemical control for the ants is toxic bait. However, the active ingredients in these baits have been restricted by forest certification organizations, justifying the search for new active compounds to control these insects. Thus, this work aimed to evaluate the formicidal activity of alkaloid fractions from the roots, stems, branches and leaves of Psychotria hastisepala and Psychotria leiocarpa (Rubiaceae) against Atta sexdens Forel, 1908 (Hymenoptera: Formicidae). The alkaloid fractions were obtained from the crude methanolic extracts of P. hastisepala and P. leiocarpa by the acid-base extraction method employing liquid-liquid partitions. The fractions, previously solubilized in propanone, were applied topically to the pronotum of worker ants. Bioassays were conducted in a completely randomized design, with six replicates of each treatment and 10 ants per replicate. Insect survival was assessed daily for 21 days. The median lethal time was estimated by Weibull models. The root fractions from P. hastisepala presented the highest toxicity, followed by those from the branches, stems and leaves. Among fractions from P. hastisepala roots, the most toxic were a fraction that apparently is rich in lipophilic compounds and nonbasic alkaloids and a fraction that is likely rich in quaternary benzophenanthridine alkaloids, protopine alkaloids and tertiary bases. Psychotria leiocarpa fractions were not toxic to this insect. Psychotria hastisepala is potentially useful for the development of new products for A. sexdens control