This article provides a literature review pointing out the relevance of plant extracts as an economically possible and ecologically sustainable alternative to the use of chemical compounds in the management and control of the insects in agriculture. The methodology was constituted in a literature review, through researches in Scielo and Lilacs, from 1990 to 2018. Organic farming is gaining importance in the Brazilian economy. The consumers are more and more conscious and demanding, choosing healthy foods, free from chemical residuals, deemed as harmful to the health. Botanic extracts can control insects and pathogens, providing no contamination for the soil, for the drinkable water sources, and leaving no toxic residuals in the environment. Studies focused on production and testing of these natural products deserve to be highlighted in the scientific literature. Only through the spreading of these studies, small producers and family farmers will access these informations.
The aim of this study was to analyze the effect of essential oils on the control of soft rot of kale. Clove essential oil at 0.25%, lemongrass and palmarosa essential oils at 0.5%, melaleuca and orange essential oils at 0.75%, bergamot, rosemary, sage and ginger essential oils at 1% were evaluated for the in vitro inhibition of Pectobacterium carotovorum subsp. brasiliensis (Pcb) and control of soft rot of kale, sprayed 72 hours before or seven hours after inoculation. Clove, citronella, bergamot, rosemary, palmarosa, sage, melaleuca, and lemongrass oils completely inhibited the growth of Pcb. Lemongrass oil (0.5%) caused 0% of disease incidence (INC), providing 100% of disease control in both periods of inoculation. Clove oil (0.25%) showed a lower INC (25%) when applied after inoculation, providing a control percentage of 71.42%. The lemongrass and clove essential oils were analyzed by GC/FID (Gas Chromatography – Flame Ionization Detector) and by GC/MS (Gas Chromatography /Mass Spectrometer). The major components were eugenol (91,9%) for clove oil and citral, isometric mixture of neral (34,1%) and geranial (42,9%) for lemongrass oil. The Minimum inhibitory concentration (MIC) of lemongrass, clove oils and their major components (citral and eugenol, respectively) was determined by using a broth macrodilution technique, as well as they were evaluated at different concentrations on the control of soft rot of kale, sprayed according descriptions above. The MIC was 0.03125% for citral, and 0.0625 and 0.125% for lemongrass and clove oils, respectively. Eugenol didn't show MIC. Lemongrass oil at 0.125% (post-inoculation) and citral at 0.125% (pre and post-inoculation) provided the highest percentages of disease control (33.33, 50, and 100%, respectively). Clove oil at 0.125% (post-inoculation) showed better effectiveness than eugenol (0.25%), providing a percentage of disease control of 16.67%. Lemongrass and clove essential oils were the most effective in control of soft rot of kale, suggesting that these oils have a potential to be used as antibacterial agents.
Dois experimentos foram conduzidos em viveiro de mudas e casa de vegetação em Juazeiro-BA. Foram utilizadas estacas semilenhosas dos clones CCN-51, PS-1319 e PH-16, com 3 a 4 gemas. Posteriormente, as estacas de CCN-51 e PS-1319 foram submetidas a concentrações de 0, 2000, 4000 e 6000 mg.L-1 de AIB realizando-se imersão de suas bases pelo tempo de 10 segundos e as estacas de PH-16 foram tratadas com 0, 300, 600 e 900 mg.L-1 de AIB com imersão de suas bases por 24 h. Logo após, as estacas foram colocadas em sacos de poliestireno, contendo substrato à a base de areia, esterco e terra vegetal na proporção de 3:2:1, respectivamente. Os experimentos foram avaliados aos 60 dias da instalação. As estacas utilizadas no experimento I apresentaram baixo índice de sobrevivência, brotação e formação de calos. De forma similar o experimento II apresentou baixo índice de sobrevivência e formação de calos, porém não ocorreram brotações, sendo que nos dois experimentos não houve formação de raízes.
O experimento foi desenvolvido baseado na importância do fator nutricional da cunhã para animais de grande e pequeno porte, e no crescimento desta forrageira em solos típicos da região semiárida, que geralmente apresentam salinidade natural ou proveniente da ação antropogênica. O experimento foi realizado em vasos com capacidade de 5kg, dispostos em ambiente protegido com insolação plena, no Departamento de Tecnologia e Ciências Sociais (DTCS) da UNEB Campus III em Juazeiro - BA. Avaliouse o efeito de sete diferentes concentrações salinas em níveis crescentes de condutividade elétrica da água de irrigação - CEa (0; 2; 4; 6; 8; 10 e 12dS/m), a temperatura ambiente. As análises do cultivo foram realizadas a cada sete dias e observaramse número de folhas, diâmetro do colo da planta, comprimento da planta e teor de clorofila total aos 13; 20; 27; 34 e 40 dias após o início da irrigação com soluções salinas. Os teores de prolina, a relação parte aérea/raiz (PA/Rz), o comprimento radicular e o teor de água foram avaliados no 40º dia do experimento após o início dos tratamentos. Os resultados mostraram que a elevação da CEa afetou todas as variáveis analisadas.
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