Xanthotoxin: An Aphicidal Coumarin From Ficus petiolaris against Melanaphis sacchari Zehntner (Hemiptera: Aphididae).

In this research, we evaluated the aphicidal effect of the ethanolic extract of stems and bark of Ficus petiolaris Kunth (Moraceae), in laboratory bioassays in an artificial diet against apterous adult females of Melanaphis sacchari Zehntner (Hemiptera: Aphididae). The extract was evaluated at different concentrations (500, 1,000, 1,500, 2,000, and 2,500 ppm), and the highest percentage of mortality (82%) was found at 2,500 ppm after 72 h. The positive control imidacloprid (Confial®) at 1% eliminated 100% of the aphids, and the negative control (artificial diet) only presented mortality of 4%. The chemical fractionation of the stem and bark extract of F. petiolaris yielded five fractions of FpR1-5, which were each evaluated at 250, 500, 750, and 1,000 ppm. FpR2 had the strongest aphicidal effect, with 89% mortality at 72 h at 1,000 ppm. The pure xanthotoxin compound extracted from this fraction was even more effective, with 91% aphid mortality after 72 h at 100 ppm. The lethal concentration (LC50) of xanthotoxin was 58.7 ppm (72 h). Our results indicate that the extract of F. petiolaris showed toxic activity against this aphid, and its xanthotoxin compound showed strong aphicidal activity at low concentrations.

Effect of Salicylic Acid in the Yield of Ricinine in Ricinus communis under Greenhouse Condition.

Castor bean (Ricinus communis) seeds contain ricinine, an alkaloid with insecticidal and insectistatic activities. Elicitation with salicylic acid (SA) has proven to stress R. communis and might modify the ricinine concentration. The aim of this study was to evaluate the concentration of ricinine in the bagasse of seeds from R. communis elicited with exogenous SA under greenhouse conditions. Plants were grown and divided into five groups, which were sprayed with SA and drench with 50 mL 60 days after sowing with concentrations of SA (0, 100, 300, 600 and 900 µM). Clusters were mixed and separated according to the treatment, and dried. The seeds were ground, the oil was extracted by Soxhlet with hexane, and then the bagasse was extracted with methanol. Ricinine was determined by HPLC. Elicitation did not change the plant height or diameter; the control group had 9.17 µg mL-1 of ricinine; and the concentrations followed a hormesis curve with the peak at 300 µM of SA that had a ricinine concentration of 18.25 µg mL-1. Elicitation with SA might be a cost-effective technique to increase ricinine from R. communis bagasse.

Distribución potencial de dos subespecies de Montanoa tomentosa (Asteracerae) en México / Potential distribution of two subspecies of Montanoa tomentosa (Asteracerae) in Mexico

Introducción: la Montanoa tomentosa es un recurso fitogenético con propiedades medicinales utilizado en México. A pesar de su relevancia botánica, la información específica de las distribuciones de taxones infraespecíficos y la los factores que influyen en su desarrollo aún son limitados. Objetivo: Informar el potencial geográfico distribución y las variables ambientales asociadas a nichos ecológicos de dos subespecies de M. tomentosa (M. tomentosa subsp. Tomentosa y M. tomentosa subsp. Xanthiifolia) en territorio mexicano. Métodos: A Se creó una base de datos de registros de herbario, se realizó una búsqueda sistemática in situ de ambas subespecies desde Octubre de 2015 a marzo de 2016, durante la temporada de floración y fructificación. Posteriormente, recorridos exploratorios (Guanajuato, Querétaro, Hidalgo, Ciudad de México, Estado de México, Puebla, Oaxaca y Chiapas). Un total de 181 Se muestrearon y georreferenciaron individuos, generando nuevos registros para la actualización de la base de datos. Tres hábitat modelos de idoneidad (complejo M. tomentosa, M. tomentosa subsp. tomentosa y M. tomentosa subsp. xanthiifolia) se generaron utilizando el software MaxEnt. Este software estima la probabilidad de distribución de especies. utilizando datos georreferenciados y características ambientales como predictores, mediante el logaritmo de entropía máxima y el método bayesiano. Resultados: De 22 variables ambientales utilizadas como predictores, cinco (estacionalidad de temperatura, isotermalidad, temperatura máxima del mes más cálido, precipitación del más cálido trimestre y precipitación del trimestre más húmedo) contribuyeron con el 70,2% de la contribución porcentual total. los El modelo mostró una distribución potencial de 77 688 km2, aproximadamente el 4% del territorio de la República Mexicana. Ambos La subespecie creció entre 500 y 2 500 m. Se asociaron a vegetación xerófila y heliófila, a veces también estaban ubicadas en la periferia o incrustadas en aberturas de bosques templados y subhúmedos. No estuvieron presentes regiones secas del norte del país. Conclusiones: estacionalidad de la temperatura, isotermalidad y la temperatura máxima del mes más cálido determinan la distribución de la especie. Precipitación del cuarto más cálido y la precipitación del cuarto más húmedo define el hábitat entre M. tomentosa subsp. tomentosa y M. tomentosa subsp. xanthiifolia. Estos hallazgos aclaran las preferencias ecológicas y la delimitación los taxones infraespecíficos de M. tomentosa.

Introduction: Montanoa tomentosa is a phytogenetic resource with medicinal properties used in Mexico. Despite its botanic relevance, the specific information of infraespecific taxa distributions and the environmental factors that influence their development is still limited. Objective: To report the potential geographic distribution and the environmental variables associated to ecological niches of two subspecies of M. tomentosa (M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia) in the Mexican territory. Methods: A database of herbarium records was created, an in situ systematic search of both subspecies was carried out from October 2015 to March 2016, during the flowering-fruiting season. After that, exploratory tours (Guanajuato, Querétaro, Hidalgo, Mexico City, State of Mexico, Puebla, Oaxaca and Chiapas) were realized. A total of 181 individuals were sampled and georeferenced, generating new records for the database upgrading. Three habitat suitability models (M. tomentosa complex, M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia) were generated using the MaxEnt software. These software estimates the probability of species distribution using geo-referenced data and environmental characteristics as predictors, through the maximum entropy logarithm and the Bayesian method. Results: From 22 environmental variables used as predictors, five (seasonality of temperature, isothermality, maximum temperature of the warmest month, precipitation of the warmest trimester and precipitation of the wettest trimester) contributed 70.2 % of the total percentage contribution. The model showed a potential distribution of 77 688 km2, approximately 4 % of the Mexican Republic territory. Both subspecies grew between 500 and 2 500 m. They were associated to xerophilous and heliophiles vegetation, sometimes they were located in the periphery or embed in openings of temperate and sub-humid forests too. They were not present dry regions from the North of the country. Conclusions: Temperature seasonality, isothermality and maximum temperature of the warmest month determine the distribution of the species. Precipitation of the warmest quarter and precipitation of wettest quarter defines the habitat between M. tomentosa subsp. tomentosa and M. tomentosa subsp. xanthiifolia. These findings clarify the ecological preferences and delimitation the infraspecific taxa of M. tomentosa.

Composition of the Essential Oil of Salvia ballotiflora (Lamiaceae) and Its Insecticidal Activity.

Essential oils can be used as an alternative to using synthetic insecticides for pest management. Therefore, the insectistatic and insecticidal activities of the essential oil of aerial parts of Salvia ballotiflora (Lamiaceae) were tested against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The results demonstrated insecticidal and insectistatical activities against this insect pest with concentrations at 80 µg·mL(-1) resulting in 20% larval viability and 10% pupal viability. The larval viability fifty (LV50) corresponded to a concentration of 128.8 µg·mL(-1). This oil also increased the duration of the larval phase by 5.5 days and reduced the pupal weight by 29.2% withrespect to the control. The GC-MS analysis of the essential oil of S. ballotiflora showed its main components to be caryophyllene oxide (15.97%), and ß-caryophyllene (12.74%), which showed insecticidal and insectistatical activities against S. frugiperda. The insecticidal activity of ß-caryophyllene began at 80 µg·mL(-1), giving a larval viability of 25% and viability pupal of 20%. The insectistatic activity also started at 80 µg·mL(-1) reducing the pupal weight by 22.1% with respect to control. Caryophyllene oxide showed insecticidal activity at 80 µg·mL(-1) giving a larval viability of 35% and viability pupal of 20%.The insectistatic activity started at 400 µg·mL(-1) and increased the larval phase by 8.8% days with respect to control. The LV50 values for these compounds were 153.1 and 146.5 µg·mL(-1), respectively.