Toxicity of Varronia curassavica Jacq. Essential Oil to Two Arthropod Pests and Their Natural Enemy.

This study aimed to evaluate the toxicity of the Varronia curassavica Jacq. essential oil to two cosmopolitan and polyphagous pest species, the two-spotted spider mite (Tetranychus urticae Koch) and the green aphid (Myzus persicae Sulzer). Additionally, we tested the essential oil toxicity to a generalist predatory insect, the green lacewing Ceraeochrysa cubana Hagen. The treatments consisted of four essential oil concentrations (0.25, 0.5, 0.75 and 1.0%) and one control (Tween® 80 + water). At 0.75% concentration, the V. curassavica essential oil caused the highest mortalities for both pests. The concentration of 1.0% of the essential oil interfered mainly in the rates of oviposition and egg hatching and caused a decrease in the instantaneous population growth rate (ri) of T. urticae. Survival of the C. cubana was not affected by the highest tested concentration of the essential oil (1%). Tested concentrations V. curassavica essential oil were toxic to T. urticae and M. persicae, but not to the predator C. cubana.

Lettuce and marigold intercropping: crops productivity and marigold's flavonoid content / Consórcio entre alface e calêndula: produtividade das culturas e teor de flavonóides em calêndula

ABSTRACT: Intercropping of vegetables and medicinal plants might produce favorable interactions for both crops, resulting in increased production and profit per unit area. It is known that active compounds can change because of several factors, including the cropping system. Therefore, the goal of this study was to evaluate the effect of intercropping of lettuce and marigold on the productivity of these crops and on the flavonoid content of marigold flowers. The experiment was conducted in the experimental area of EPAMIG in Oratorios-MG. Treatments consisted of lettuce + marigolds intercropping between rows, lettuce + marigold intercropping between plants, and monocultures of each species. Spacing was 0.3x0.3m. The experimental design consisted of randomized blocks with ten repetitions. Harvest of lettuce and marigold flowers started 45 days after transplantation (DAT) and extended up to 72 DAT for marigolds. Lettuce and marigold intercropping appears feasible because lettuce production did not differ between the monoculture and intercropped cultivations, and marigold productivity was higher when intercropped with lettuce. No change in the flavonoid (active chemicals of medicinal interest) content in the floral capitula of marigolds was observed.

RESUMO: O cultivo consorciado entre hortaliças e plantas medicinais pode promover interação benéfica entre as duas culturas, resultando em aumento na produção e no lucro por unidade de área. Sabe-se também que os princípios ativos podem ser alterados por vários fatores, incluindo o sistema de cultivo. Dessa forma, o objetivo do presente trabalho foi avaliar o efeito do consórcio entre alface e calêndula na produtividade destas culturas e no teor de flavonoides em flores de calêndula. O experimento foi conduzido na área experimental da EPAMIG, em Oratórios-MG. Os tratamentos consistiram em: alface + calêndula entre linhas, alface + calêndula entre plantas e os monocultivos de alface e de calêndula. O espaçamento utilizado foi de 0,3x0,3m. O delineamento experimental foi em blocos casualizados com dez repetições. A colheita de alface e das flores de calêndula iniciou-se 45 dias após o transplantio (DAT), sendo a colheita de calêndula estendida até os 72 DAT. O consórcio entre alface e calêndula é viável, pois a produção da alface é semelhante entre sistemas consorciados e cultivo solteiro, e a produtividade da calêndula é maior quando consorciada com a alface, não havendo alteração no teor de flavonoides (princípio ativo de interesse medicinal) dos capítulos florais de calêndula.

Effect of Accessions and Environment Conditions on Coumarin, O-Coumaric and Kaurenoic Acids Levels of Mikania laevigata.

Coumarin, o-coumaric, and kaurenoic acid are bioactive compounds usually found in the leaves of Mikania laevigata. Genetic and environmental variations in the secondary metabolites of plants may have implications for their biological effects. Three different accessions of M. laevigata cultivated in four sites between the Equator and the Tropic of Capricorn in Brazil were evaluated aiming to present potential raw materials and discuss relationships among these three bioactive compounds. The results revealed effects of plant accessions and environmental factors and suggested two contrasting chemical phenotypes of M. laevigata. The first phenotype presented the highest levels of kaurenoic acid (2283 ± 316 mg/100 g) besides lower levels of coumarin (716 ± 61 mg/100 g), which was also stimulated by the environment and mild climate at the site nearest to the Tropic of Capricorn. The other phenotype presented the lowest levels of kaurenoic acid (137 ± 17 mg/100 g) besides higher levels of coumarin (1362 ± 108 mg/100 g), which was also stimulated by the environment and tropical climate at the site nearest to the Equatorial beach.