No abstract

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

ABSTRACT. The aim of this study was to evaluate the insecticide effect of watery leaf extracts of Ruta graveolens (Rutaceae), alcoholic leaf extracts of Copaifera langsdorffii (Caesalpinaceae) and Chenopodium ambrosioides (Chenopodiaceae) in the concentration of 5% under field conditions. The experiment design was randomized blocks with six replications. The parcels treated with plant extracts showed reduction in the population of pests when compared with the control parcels. The extract elaborated with C. langsdorffii presented greater insecticidal effect under Bemisia tabaci (Hemiptera: Aleyrodidae) and sum of pests. It was verified that after 24 hours of spraying, the parcels treated with the extract of C. ambrosioides presented minor numbers of adults of Tuta absoluta (Lepidoptera: Gelechiidae), followed by the parcels treated with extract of R. graveolens. There were smaller numbers of parasitoid eggs of lepidopterans Trichogramma sp. (Hymenoptera: Trichogrammatidae) and sum of natural enemies (predators + parasitoids) in the parcels that had received spraying with extracts from the plants of C. langsdorffii and C. ambrosioides, followed by R. graveolens, compared to the control. There were a smaller number of parasitoids from the family Eulophidae (Hymenoptera) attacking caterpillars of T. absoluta in plants treated with R. graveolens, followed by C. langsdorffii and C. ambrosioides than in the control. RESUMO. Ação inseticida de Ruta graveolens, Copaifera langsdorffii e Chenopodium ambrosioides sobre pragas de tomate. O objetivo deste trabalho foi avaliar o efeito inseticida dos extratos aquosos de folhas de Ruta graveolens (Rutaceae) e alcoólicos de folhas de Copaifera langsdorffii (Caesalpinaceae) e de folhas de Chenopodium ambrosioides (Chenopodiaceae) a 5%. O experimento foi em blocos casualizados com seis repetições. As parcelas tratadas tiveram redução na população de pragas, quando comparadas às parcelas sem nenhum tratamento. O extrato elaborado com C. langsdorffii apresentou maior efeito inseticida em Bemisia tabaci (Hemiptera: Aleyrodidae) e soma das pragas. Verificou-se que após 24h de pulverização, as parcelas tratadas com o extrato de C. ambrosioides apresentaram menores números de adultos de Tuta absoluta (Lepidoptera: Gelechiidae) seguido pelas parcelas tratadas com extrato de R. graveolens. Foram observados menores números do parasitoide de ovos de lepidópteros Trichogramma sp. (Hymenoptera: Trichogrammatidae) e da soma dos inimigos naturais (predadores + parasitoides) nos tratamentos que receberam as pulverizações com os extratos das plantas de C. langsdorffii e C. ambrosioides seguido por R. graveolens do que na testemunha; do parasitoide da família Eulophidae (Hymenoptera), que atacam lagartas de T. Absoluta em plantas tratadas com R. graveolens, seguido por C. langsdorffii e C. ambrosioides do que na testemunha.Palavras-chave: Lycopersicon esculentum, bioinseticida, controle alternativo.

No abstract

Growth-promoting bacteria are already used in sustainable agricultural systems in Brazil. The market is dominated by inoculants and biological pesticides, which do not reach the full potential of this tool in the agricultural sector. This study aimed to evaluate four bacterial strains for the presence of growth promotion mechanisms, as well as the reduction of Asian rust severity in soybean plants and its effects on three antioxidant enzymes during pathogenesis. The plants were treated using the bacterial cells and/or their biosurfactants before inoculation of the pathogen (IOP). Severity was measured based on a diagrammatic scale at 14, 18 and 21 days after IOP, and the activities of the enzymes SOD, CAT, and APX were evaluated 21 days after IOP. Treatments containing only bacterial cells were not efficient in reducing the severity, with losses of leaf area reaching 15%, while the addition of biosurfactants led to a result that is similar to the biofungicide, based on Bacillus subtilis (Serenade®). The presence of direct growth promotion mechanisms can be observed in all isolates, as well as the role of bacterial metabolites, especially lipopeptides, in the biological control of diseases and the modulation of the plant’s immune response.