In the Northwest of Mexico, Phenacoccus solenopsis has been recognized as an aggressively invasive species on cotton plants. Therefore, the aim of the present study was to evaluate the effectiveness of two fungal commercial bioinsecticides (Verticillium lecanii and Isaria fumosorosea) against P. solenopsis under laboratory and semi-felds conditions. Our results showed a high mortality by V. lecanii (100%) followed by I. fumosorosea (40%) and control (0%) after 96 h of exposure. Thirty days after initiating the experiment, we observed a significant reduction of the disease index in cotton plants exposed to I. fumosorosea and V. lecanii (50% and 48%, respectively) compared with control (76%). The use of V. lecanii and I. fumosorosea did not show significant changes in the physiological parameters of plants (chlorophyll, polyphenol contents, anthocyanins and potential photochemical yield values) compared with the control after 30 days of exposure to entomopathogenic fungi. Currently, the available information about mode of action of commercial formulations using I. fumosorosea and V. lecanii for biocontrol of P. solenopsis is scarce in Mexico compared with other countries. Therefore, studies focused on their effectiveness are necessary.

En el noroeste de México, Phenacoccus solenopsis ha sido reconocida como una especie agresivamente invasiva en plantas de algodón. Por lo tanto, el objetivo del presente estudio fue evaluar la efectividad de dos bioinsecticidas fúngicos comerciales (Verticillium lecanii e Isaria fumosorosea) contra P. solenopsis en condiciones de laboratorio y semi-campo. Nuestros resultados mostraron una alta mortalidad por V. lecanii (100%) seguida de I. fumosorosea (40%) y control (0%) después de 96 horas de exposición. Después de treinta días de iniciar el experimento, se observó una reducción significativa del índice de severidad en plantas de algodón expuestas a I. fumosorosea y V. lecanii (50% y 48%) comparada con el control (76%). El uso de V. lecanii e I. fumosorosea no mostró cambios significativos en los parámetros fsiológicos de las plantas (valores de clorofla, contenido de polifenoles, antocianinas y eficiencia fotosintética) con respecto al control después de 30 días de exposición a los hongos entomopatógenos. Actualmente, la información disponible sobre el modo de acción de la formulación comercial empleando I. fumosorosea y V . lecanii para el control biológico de P. solenopsis es escasa en México en comparación con otros países. Por lo tanto, son necesarios estudios enfocados en su efectividad.

ABSTRACT The aim of the present work is to evaluate the changes on the phenylalanine ammonia lyase (PAL) activity, phenolic compounds accumulation and photochemical efficiency in leaves of P. glandulosa treated with Cd2+ (0.001 M) and Cu2+ (0.52 M) concentrations for 96 h under hydroponic conditions. The results showed that only leaves treated with copper had a decrease in photochemical efficiency and leaf epidermal polyphenols in P. glandulosa leaves after 96 h of exposure. On the other hand the reverse-phase HPLC analysis revealed higher levels of phenolic compound (gallic, vanillic and caffeic acids) and flavonoids (rutin and kaempferol-3-O-glucosides) in plant leaves from Cu and Cd-treatments with respect to control plants. Finally, highest increments in PAL activity was observed in extracts of leaves treated with Cu and Cd (about 205 and 284%), respectively, with respect to control plants after 96 h treatment. These suggest that activation of phenylpropanoid pathway represent a source of nonenzymatic antioxidants that protect at P. glandulosa against oxidative stress when exposed to cadmium and copper. Hence future studies are necessary to elucidate the participation of phenylpropanoid pathway in the reduction of metal toxicity in Prosopis species.

In the present study the production of phenolic acids and flavonoid compounds by E. gracilis exposed to two cadmium concentrations (0.02 and 0.14 mM) was evaluated using high-performance liquid chromatography (HPLC). The results showed that E. gracilis exposed to 0.02 mM Cd+2 increased significantly the total content of phenolic compounds (798.46 ± 12.61 μg GA/g) and total flavonoids (241.34 ± 47.63 μg QE/g) with respect to the control (137.34 ± 19.80 μg QE/g DW and 549.00 ± 8.57 μg GA/g DW, respectively). However, no significant increase in the total content of phenolic compounds (568.54 ± 17.42 μg GA/g DW) and total flavonoids (141.11 ± 9.36 μg QE/g DW) were observed in E. gracilis exposed to 0.14 mM Cd+2. Further research is necessary to determine the specific role of flavonoids in E. gracilis exposed to high concentrations of Cd+2.

En el presente estudio la producción de compuestos fenolicos y flavonoides producidos por E. gracilis expuesto a dos concentraciones de cadmio fue evaluado usando cromatografía liquida de alta precisión (HPLC). Los resultados mostraron que 0.02 mM de Cd+2 incrementaba significativamente el contenido total de compuestos fenolicos (798.46 ± 12.61 μg GA/g) y flavonoides (241.34 ± 47.63 μg QE/g) con respecto al control (137.34 ± 19.80 μg QE/g DW y 549.00 ± 8.57 μg GA/g DW) respectivamente. Sin embargo, incrementos no significativos en el contenido de compuestos fenolicos (568.54 ± 17.42 μg GA/g DW) y flavonoides totales (141.11 ± 9.36 μg QE/g DW) fueron observados en E. gracilis expuestas a 0.14 mM de Cd+2. Futuros estudios son necesarios para determinar la función especifica de los flavonoides en E. gracilis expuesto a altas concentraciones de Cd+2.

The effect of phenolic and carotenoid extracts from chiltepin fruits on mycelial growth and the inhibition of conidial germination of Alternaria alternata and Fusarium oxysporum were investigated in the present work. Phenolic extracts inhibited mycelial growth of A. alternata by 38.46%, and significantly reduced conidial germination on the fifth day after treatment to 92% in relation to control. No significant changes were observed in the inhibition of mycelial growth in Fusarium oxysporum; however, the number of germinated conidia was reduced, showing 85% inhibition five days after treatment in relation to control. Moreover, carotenoid extracts showed 38.5% inhibition of mycelial growth and 85.3% inhibition of conidial germination of A. alternata, five days after treatment. Carotenoid extracts showed less inhibition of mycelial growth (20.3%) in F. oxysporum, with respect to A. alternata; while there was greater inhibition of conidial germination (96%) on the fifth day after treatment. Phenolic and carotenoid extracts from chiltepin may be a promising alternative as a natural fungicide against fungi of agricultural importance.

En el presente estudio se evaluó el efecto de extractos fenólicos y de carotenoides procedentes de frutos de chiltepín sobre el crecimiento micelial y la germinación de conidios de Alternaria alternata y Fusarium oxysporum, 2 importantes hongos causantes de podredumbres en frutas y hortalizas. Los extractos fenólicos presentaron una inhibición en el crecimiento micelial de A. alternata del 38,46 %, y redujeron significativamente la germinación de conidios al quinto día después del tratamiento al 92 % en relación al control. No se observaron cambios significativos en el crecimiento micelial de F. oxysporum, pero sí se redujo significativamente al 85 % en relación al control, el número de conidios germinados a los 5 días de tratamiento. Los extractos de carotenoides mostraron una inhibición del 38,5 % en el crecimiento micelial y del 85,3 % en la germinación de conidios de A. alternata, 5 días después del tratamiento. Frente a F. oxysporum, dichos extractos presentaron menor inhibición del crecimiento micelial (20,3 %), mientras que hubo una mayor inhibición en la germinación de conidios (96 %). Los extractos fenólicos y de carotenoides de chiltepín pueden ser una alternativa promisoria de importancia agrícola como fungicidas naturales.