Corymbia citriodora and Cymbopogon nardus essential oils samples were analyzed by GC and GC-MS and their qualitative and quantitative compositions established. The main component of essential oils of C. citriodora and C. nardus was citronellal, at 61.78% and 36.6%, respectively. The essential oils and citronellal were tested for their fumigant antifungal activity against Pyricularia (Magnaporthe) grisea, Aspergillus spp., and Colletotrichum musae. The minimum inhibitory concentration (MIC) ranged from 100 to 200 ppm for the essential oils and 25 to 50 mg·mL−1 for citronellal. The contact assay using the essential oils and citronellal showed growth inhibition of the three fungal species. However, a concentration of 1.47 mg·mL−1 only reduced the inhibition of Aspergillus growth to 90% at 14 days of exposure. For the fumigant assay, 0.05, 0.11, and 0.23 mg·mL−1 of essential oils and citronellal drastically affected growth of P. grisea, Aspergillus spp., and C. musae. Harmful effects on the sporulation and germination of the three fungi were seen, and there was complete inhibition at 0.15 mg·mL−1 with both oils and citronellal. This showed that the crude component of essential oils of C. citriodora and C. nardus markedly suppressed spore production, germination, and growth inhibition of P. grisea, Aspergillus spp., and Colletotrichum musae.

Essential oils are alternative to control pathogenic agents, agricultural pests and weeds, with the use of pesticides in agriculture has been an important tool in the control of many pathogenic microorganisms and plants to increase production, but the indiscriminate use of these chemicals has negatively affected the environment and human health. It has been researched lately, demand for new plants with metabolic molecules such as terpenes, alkaloids and phenolic compounds, in effect; bioinsecticide, biofungicide bioherbicida and plants that can replace chemicals or with low or no residual power and reduce the impact to environment, this manuscript aims to give a comprehensive explanation on the importance of essential oils and their secondary metabolites in plant defense. The use of plants with insecticidal properties, fungicide and herbicide, shows a high potential of this tool in the management of pests, diseases and weeds. For the final insertion and safe botanical products in agriculture, however, more studies are still needed.

O objetivo deste estudo foi avaliar os efeitos dos óleos essenciais C. nardus, E. citriodora e composto citronelal da germinação associada à micoflora e milho inicial da planta (Zea Mays) nas doses de 5, 10 e 15% para todos os testes. A cultivar de milho utilizada foi XGN5320 e o delineamento experimental foi inteiramente casualizado. Após a aplicação de doses definidas, a germinação foi avaliada no papel do germiteste na DBO. A avaliação da fitotoxicidade foi realizada em plantas cultivadas em vasos com aplicação direta nas plantas e nos sintomas observados 48 e 96 horas após a aplicação. Também avaliamos o tamanho das mudas e raízes. A matéria seca foi obtida após essas partes permanecerem na circulação forçada de ar dos gases. O efeito na micoflora das sementes foi observado pelo método Blotter. Os resultados mostraram que os óleos utilizados não eram seletivos para plantas de milho, causando danos graves no desenvolvimento inicial de fitotoxicidade dos mesmos, com consequente redução na massa seca e no comprimento da parte aérea (P <0,05). Os óleos inibiram dramaticamente os fungos transmitidos pelas sementes, Aspergillum ssp inibindo satisfatoriamente. e levado à incidência de Colletotrichum, Fusarium e Penicillium zero, com a dose mais alta (15%), indicando toxicidade para esses microrganismos. No entanto, mostrou atividade alelopática, afetando dramaticamente a germinação das sementes.

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Carotenoids are isoprenoid pigments used in food, chemical, textile, pharmaceutical, and cosmetic industries. They act not only as dyes and provitamins A but also have antioxidants, photoprotective, antimicrobial properties, among others. This class of pigment can be obtained traditionally by plants or chemical synthesis, but they have some disadvantages. In recent years, search for alternative sources has been an important strategy for the carotenoid industries. Microbial synthesis is an alternative that has shown good yields, speed, and reduced production costs. Hostile environments, such as the Caatinga domain, represent an interesting source of microorganisms that produce biomolecules, especially carotenoids, because of oxidative stress caused by sunlight. Thus, this region has been attracting the attention of the scientific community and industry for the use of these organisms in the production of carotenoids and applications in cosmetic products; since these compounds have interesting antioxidant and photoprotective properties. In this review, general characteristics of carotenoids, sources of production, industrial applicability, and commercialization will be discussed, as well as perspectives on the production of carotenoids from microorganisms isolated from the Caatinga and their application in anti-UV products.

RESUMO: O uso de cultivares de soja resistente a insetos-praga é uma alternativa de controle que diminui os custos de produção e não causa desequilíbrio no agroecossistema. Assim, objetivou-se com este trabalho avaliar se diferentes densidades de plantio influenciam a suscetibilidade de cultivares de soja a Cerotoma arcuata Oliver (Coleoptera: Chrysomelidae) no estado do Tocantins. Para tanto, foram conduzidos ensaios de preferência com chance de escolha em laboratório utilizando os cultivares de soja P98Y70, M8766RR e M9144RR. A preferência dos insetos variou em função da cultivar. Os tricomas desempenham papel importante na proteção das plantas ao ataque da C. arcuata, de forma que o cultivar M8766RR apresenta resistência do tipo não-preferência para alimentação deste desfolhador. PALAVRAS-CHAVE: defesas morfológicas, manejo de resistência, relação inseto-planta.