One of the main pathological problems for cropping sacha inchi (Plukenetia volubilis L.) is its susceptibility to root-knot nematodes (Meloidogyne incognita). In this study, fungal endophytes were explored in the stems and leaves of seven species of the Plukenetia genus, and also evaluated the abilities of isolates of Trichoderma and Clonostachys as biocontrol agents against damages caused by this nematode in sacha inchi. In order to evaluate such effects, seedlings were colonized with these fungal isolates, and then they were infested with root-knot nematode eggs. The results showed that the Plukenetia genus is rich in diversity of fungal endophytes. Their greatest diversity was found in Plukenetia brachybotria. Among the most efficient isolates for endophytic colonization, some of Trichoderma (e.g., kmd-36 and kmd-54) and others of Clonostachys (e.g., kmd-68 and kmd-80) provided a significant (p < 0.05) reduction in the number of galls induced by the nematodes, in comparison to the control treatment without endophytic colonization. In addition, these isolates allowed a better root development in the tested plants, thus revealing a good biocontrol potential against M. incognita in sacha inchi.

El presente trabajo se desarrolló con el objetivo de determinar la respuesta de accesiones de sacha inchi Plukenetia volubilis L. a la infestación del nematodo Meloidogyne incognita en condiciones controladas. Para ello se propagaron cinco accesiones de sacha inchi (Mishquiyacu, Chazuta, Shica, Pinto Recodo y Sauce) mediante enraizamiento de estacas. Las estacas enraizadas fueron repicadas en macetas de 2 kg que contenían sustrato estéril. Cuando las plántulas iniciaron la emisión de los brotes fueron infestadas  con huevos de M. incognita a una dosis de 500 huevos por maceta. Posteriormente, las plántulas fueron incubadas durante 35 días a temperatura ambiente de vivero. Finalizado el periodo de incubación se cuantificó el número de nódulos por sistema radicular, midiéndose la longitud de las raíces. Con ambos datos, número de nódulos y longitud de raíces (transformados a logaritmo de base diez), se realizaron los análisis de varianza y las  medias fueron comparadas usando la  prueba de Duncan (P=0,05). En raíces  de las  accesiones Mishquiyacu y Chazuta se encontró significativamente menor número de nódulos y mayor longitud de raíz.  Pinto Recodo y Sauce registraron mayor número de nódulos y menor longitud de raíz, mientras que Shica registró menor número de nódulos y longitud de raíz. Según este estudio las accesiones Mishquiyacu y Chazuta muestran tolerancia a M. incognita y pueden ser utilizadas en futuros estudios sobre manejo integrado del cultivo de sacha inchi.

Coffee leaf rust (CLR) is a fungal infection which is devastating susceptible coffee plantations throughout the South American region in the last years. The objective of this study was to analyze the effects of shade trees management and pruning in two coffee varieties against coffee leaf rust in the Peruvian Amazon. The experimental design was a randomized complete block with factorial scheme 2A×2B×4C with 16 treatments and four repetitions, making a total of 64 experimental units, in which each experimental unit had 16 coffee plants. The studied factors were agroforestry system (A), coffee varieties (B), and pruning methods (C). The data were statistically examined by analysis of variance and mean comparisons using Tukey test. It was found that plant growth was favored by the use Inga shade and recepa pruning in Typica variety. Also, the use of polyculture-shaded coffee with about 40 % of shadow, and recepa, a pruning method which consists of cutting the stem of the coffee plants at 40 cm from the ground, reduce the incidence and severity of CLR in coffee plants. The incidence and severity of CLR was lower in the Typica variety as comparted to Pache variety. This study confirms that a shadow management and pruning coffee plants stimulate the growth of new branches and reduce incidence and severity of CLR in coffee plantations.

RESUMENEl presente estudio fue realizado con la finalidad de determinar los efectos del abonamiento nitrogenado sobre la roya amarilla (Hemileia vastatrix Berck et. Br.), causante de daños severos en los estadios iniciales de dos variedades de Coffea arabica L. Para ello se evaluaron cuatro dosis de Nitrógeno (N): 50, 75, 100 y 125 -1 Kgha , comparadas con un control absoluto. Los tratamientos con Nitrógeno recibieron dosis constantes de fósforo, potasio, magnesio y azufre. Se registró información sobre el daño ocasionado por la roya amarilla en los estadios iniciales de las variedades de café Caturra y Borbón, durante un periodo total de doce meses. Con los datos obtenidos se calculó el porcentaje del índice de intensidad de daño (%IID), lo que permitió determinar la curva de progreso de la enfermedad. El área bajo la curva de progreso de la enfermedad o AUDPC, se calculó con él %IID. Con los datos de AUDPC se realizó el análisis de variancia y la prueba de Duncan para la comparación múltiple de medias (P=0.05). Los resultados indican que no hubo un efecto significativo y diferenciado del tratamiento en la variedad, ni tampoco hubo un efecto significativo de las dosis de Nitrogeno sobre el %IID. Sin embargo, el abonamiento redujo significativamente él %IID de la RA, en los estadios iniciales de ambas variedades. PALABRAS CLAVE: Roya amarilla, Hemileia vastatrix, café, Coffea arabica, Abonamiento. EFFECTS OF NITROGEN COMPOSTING ON YELLOW RUST (Hemileia vastatrix Berck et. Br.) ABSTRACTThis study was developed with the objective of determining the effects of Nitrogen fertilization on severity of coffee rust (Hemileia vastatrix Berck et. Br.) (CR), in the early stages of development of two -1 varieties of Coffea arabica L. Four doses Nitrogen (N): 50, 75, 100 y 125 Kgha were evaluated, and compared with absolute control. The treatments with N received constant doses of phosphorus, potassium, magnesium and sulfur. For twelve months corresponding to the initial stages the development of the Caturra and Bourbon varieties, the degree of damage of CR were recorded, with these data was calculed the percentage of the damage intensity index (%IID), With it was determined the disease progress curve. The area under disease progress curve (AUDPC) was calculated with %IID data. With AUDPC data, the analysis of variance and Duncan's test for multiple comparison of means (P = 0.05) was performed. The results indicate no significant effect either of the coffee rust severity or N dose on the %IID, however fertilization reduced significantly the %IID of CR, in the early stages of development the both varieties.