No abstract

Conhecida vulgarmente como lagarta-militar ou lagarta-do-cartucho, a Spodoptera frugiperda é uma das pragas agrícolas mais importantes do Brasil, devido seu hábito polífago e sua amplas distribuição geográfica. O uso de agentes entomopatogênicos vem contribuindo com o manejo desta praga, pois diminui os impactos causados pelos agroquímicos e proporciona uma agricultura sustentável. O objetivo deste trabalho foi avaliar a patogenicidade da bactéria entomopatogênica Bacillus thuringiensis e do vírus entomopatogênico Nucleopolyhedrovirus (HearNPV) quando aplicados diretamente sobre a lagarta S. frugiperda. O experimento foi feito com lagartas de 2o e 3o instares. Cada experimento foi composto por 5 tratamentos: T1: Testemunha (sem aplicação de entomopatógenos), T2: Agree®, T3: Xentari®, T4: Diplomata®; T5: Armigen® e 5 repetições por tratamento, cada repetição contendo 6 lagartas de 2o e 3o instares. Cada repetição foi constituída de uma placa de Petri (9 cm de diâmetro) com 1 inseto, totalizando 30 lagartas de cada instar por tratamento. A mortalidade foi avaliada diariamente até quinze dias após aplicação. Os dados da mortalidade acumulada foram submetidos à análise de variância (teste F), as médias serão comparadas pelo teste Scott-Knott a 5% de probabilidade e a eficiência dos bioinseticidas pela fórmula de Abbott. O bioinseticida Xentari® proporcionou maior média de mortalidade no 2o instar de S. frugiperda diferindo dos demais tratamentos, no 3o instar não houve diferença significativa entre os tratamentos.

The conversion of forests into open areas has large effects on the diversity and structure of native communities. The intensity of these effects may vary between regions, depending on the existence of native species adapted to open habitats in the regional pool or the time since habitat change. We assess the differences in species richness and functional diversity of dung beetle communities (Coleoptera: Scarabaeinae) between native forests and novel pasturelands of the Atlantic Forest and the Cerrado, two biomes with contrasting histories of human occupation in Brazil. We conducted standardized surveys in seven forest fragments and adjacent pastures in each region and measured 14 traits in individuals collected in each type of habitat at each particular site. We calculated functional richness, functional evenness, functional divergence, and community‐weighted mean of traits for each area, and analyzed individual variation through nested variance decomposition and Trait Statistics. Communities were richer and more numerous at the Cerrado. We did not find any consistent relationship between functional diversity and forest conversion beyond the changes in species diversity. Although landscape changes were more recent at the Cerrado, the colonization of the new habitat by native species already adapted to open habitats lessens the functional loss in this biome. This indicates that habitat change's effects on trait diversity depend on the regional species pool rather than on time since land conversion. Forest conversion effects were primarily due to internal filtering. The effects of external filtering only appear at the intraspecific variance level, with contrasting differences between the Cerrado, where traits related to relocation behavior and size are selected, and the Atlantic Forest, where selection operates for traits related to relocation behavior and flight. These results evidence the importance of considering individual variance to address the responses of dung beetle communities to forest conversion.

This research, under laboratory condition, evaluated the efficiency of different strains of entomopatogenic fungus Beauveria bassiana to control leaf-cutting ant Atta sexdens rubropilosa. Soldiers and workers were inoculated with suspensions containing 1.0x107, 1.0x108, 1.0x109 and 1.0x1010 con mL-1 and maintained in B.O.D, at 25±1°C, 70% RH and 12 hours of photophase, without food. The mortality was evaluated daily, with 15 days after inoculation. Experimental design was entirely random. The sporulation data were submitted to the analysis of variance and the LT50 values (in days) were obtained through the Probit analysis. All strains of B. bassiana were pathogenic, being workers more susceptible than soldiers. The strains IBCB 21 and IBCB 07 caused high percentages of confirmed mortality showing potential for use in the control of A. sexdens rubropilosa. Strain IBCB 21 was more virulent for workers, whereas isolated IBCB 07 was more virulent for soldiers. Both isolates presented no significant difference among tested concentrations.