Browsing by Autor "M. Coca-Morante"

Now showing 1 - 6 of 6

Assessment of Lepthosphaeria polylepidis Decline in Polylepis tarapacana Phil. Trees in District 3 of the Sajama National Park, Bolivia
(2012) M. Coca-Morante
The Sajama National Park (SNP) was the first protected area (1939) in Bolivia (Fig. Nowadays it is a National Park and Natural Management Area The SNP contains a forest of the native Andean tree known as queua or quehuia (Polylepis tarapacana Phil). Forest of this type is found only in the Bolivian Andes (Argollo et al. 2006), where it suffers from human disturbance, including tree felling, man-made fires, the grazing of domestic animals Indeed, its continued existence is threatened (Rivera 1998; mentioned by Daza von Boeck 2005).
Control of Leaf Spot Diseases on Ecotypes of Faba Bean (&lt;i&gt;Vicia faba&lt;/i&gt; L.) Produced in the Andean Region of Bolivia
(Scientific Research Publishing, 2012) M. Coca-Morante; F. Mamani-Álvarez
The basin of Lake Titicaca is a faba bean-producing microregion of Bolivia where the crop is destined for export. The most commonly cultivated ecotypes “Gigante de Copacabana” and “Usnayo” are affected by diseases that can cause production losses. The aims of the present work were to identify the causal agents of leaf spot affecting these ecotypes, to record disease intensity levels, and to estimate their effect on production. In 2004 and 2005, leaflet, stem and pod samples were taken from faba bean plants with leaf spot growing in the Lake Titicaca area, and from plants in an experimental plot established to determine the effect of five different treatments on production and disease intensity: T1 = Control; T2 = seed treatment with Trichoderma sp. + alternate foliar spraying with benomyl and mancozeb; T3 = seed treatment with fludioxanil/metalaxyl M + alternate foliar spraying with benomyl and mancozeb; T4 = foliar spraying with Trichoderma sp.; T5 = alternate foliar spraying with cymoxanyl and mancozeb-chlorothalonil. Microscopic analysis of the samples revealed the presence of new fungal pathogens for faba beans in Bolivia (Cladosporium sp., and Lepthosphaerulina sp.) as well as emerging fungal pathogens (Botrytis cinerea, B. fabae, Ascochyta fabae, Alternaria sp. and Cercospora sp.). None of the treatments affected the disease progression curve (DPC) for incidence, although effects were seen with respect to disease severity. The seed + foliar treatments (T2 and T3) were more effective at controlling disease than leaf treatments on their own (T4 and T5). Modelling analysis showed faba bean leaf spot disease to be moderately destructive. Compared to chemical treatments, biocontrol with Trichoderma spp. preliminary was found to provide good control of the disease. Losses due to leaf spot disease of 36% were recorded, and a strong correlation detected between yield and disease severity.
CONTROL QUÍMICO DE SEPTORIOSIS (Septoria lycopersici SPEG.) DE LA PAPA (Solanum tuberosum Subsp. Andigena) EN ZONAS ALTOANDINAS DE ALTURA DE BOLIVIA
(2016) M. Coca-Morante; W. Castillo-Plata; A. D. Solís Méndez
En la región andina tradicional de Bolivia (>4.000 msnm) donde existen áreas importantes de producción de papa, Septoria lycopersici (conocida como Khasahui) causa pérdidas en la producción de este cultivo. Los objetivos de esta investigación fueron: evaluar el efecto de diferentes fungicidas en el control de la enfermedad estimándose la intensidad (incidencia y severidad) de la enfermedad, y las pérdidas causadas por S. lycopersici en variedades nativas comerciales. Se establecieron parcelas experimentales durante dos años agrícolas (1999/2000 y 2002/2003) en una zona Altoandina húmeda y fría (4.290 msnm) del departamento de La Paz. Se evaluaron los fungicidas: Mancozeb (Dithiocarbamato), Champion (Oxicloruro de Cobre), Bravo 500 (Clorotalonil) y Control (H2O) y las variedades andigena Waych´a Paceña e Imilla Negra (Solanum tuberosum subsp. andigena). Los fungicidas Mancozeb y Bravo alcanzaron efectos significativos en la reducción de la Curva de Progreso de la Enfermedad (incidencia y severidad) causada por S. lycopersici. Los modelos que mejor describen la curva de progreso de la enfermedad en ambas variedades son el de Gompertz y Logístico. Sin embargo, las formas linearizadas (LN) muestran tasas de infección similares y bajas, pero, se pueden considerar que muestran a una enfermedad destructiva. El efecto en la reducción de rendimiento por S. lycopersici alcanzó a 42,3 % para la variedad Waych´a y 51,5% para la variedad Imilla Negra.Fecha de aceptación: 4 de marzo, 2014
PLANTACIÓN TARDÍA DE VARIEDADES DE PAPAS (Solanum tuberoum L.) Y SU RELACIÓN CON LA VARIACIÓN CLIMÁTICA PARA REDUCIR PÉRDIDAS CAUSADAS POR EL GORGOJO DE LOS ANDES (Premnotrypes sp) Y LA SARNA POLVORIENTA (Spongospora subterranea) EN EL ALTIPLANO DE BOLIVIA
(2016) M. Coca-Morante; Z. Coronado-Lira
En el Altiplano boliviano se cultiva una gran diversidad de especies nativas andinas e introducidas, y, en los últimos años se observaron variaciones en los patrones tradicionales de cultivo de algunas especies. Los objetivos del presente estudio fueron, i. Evaluar el efecto de la plantación tardía en el rendimiento de variedades precoces y tardías de papas nativas (S. tuberosum ssp. andigena) e introducidas (Solanum tuberosum L.), y, ii. Evaluar el efecto de la incidencia de Premnotrypes sp y Spongospora subterranea en época de plantación tardía de papa en el Altiplano norte de Bolivia. Durante dos años agrícolas (2001/02 y 2002/03), se establecieron parcelas experimentales de papa en condiciones del Altiplano norte de Bolivia. Los resultados obtenidos muestran variaciones en los patrones tradicionales de cultivo de la papa. Utilizando variedades precoces y tardías, en plantación tardía (60 días después de la época tradicional), se registran rendimientos aceptables y reducción de la incidencia de Premnotrypes sp y S. subterranea. Todas las variedades completan su ciclo vegetativo indicando que las variaciones de temperaturas podrían estar afectando la fenología de las variedades y la biología del gorgojo y sarna polvorienta.Fecha de aceptación: 4 de marzo, 2014
Population structure of <i>Phytophthora infestans</i> collected from potatoes in Ecuador, Colombia, Peru, Bolivia and Uruguay
(2026) Myriam Izarra; M. Coca-Morante; Willmer G. Pérez; Laura Sanchez; Soledad Urra; Diana Valle; Viviana Lucia Cuarán; Beatriz Elena Guerra Sierra; Jan Frederik Kreuze
Abstract Late blight, a destructive disease affecting potatoes, is caused by the oomycete Phytophthora infestans and remains a critical threat worldwide. The potential for sexual reproduction in production areas near the Peru–Bolivia border remains high due to the historical presence of mating type A2 in Bolivia and the current presence of mating type A1 in Peru. In Ecuador, there has been a past coexistence of A1 ( P. infestans ) and A2 ( P. andina ), while in Colombia, P. infestans has mainly exhibited mating type A1. These neighboring countries were compared with strains from Uruguay, which historically had A2 but now shows A1. We examined the genetic structure of South American P. infestans populations using 182 isolates: 97 from Bolivia and southern Peru, 14 from Colombia, 57 from Ecuador (1993–2022), and 14 from Uruguay. The isolates were characterized by clonal lineage, mitochondrial haplotype, and mating type. In Bolivia, only the lineage/haplotype 2A1/Ia was identified, whereas Peru exhibited both 2A1/Ia and EC1/IIa, all of which were mating type A1. Puno was the sole department where both lineages were present. In older Ecuadorian populations, we found US1/Ib and EC1/IIa ( P. infestans ), as well as EC2/Ic and EC3/Ia ( P. andina ), while recent populations showed only US1. In Colombia, EC1/IIa and a new lineage, CO4 (Ia), were discovered. In Uruguay, 2A1/Ia was predominant. These results offer updated insights into the genetic diversity and geographic distribution of P. infestans across South America and aid in the development of enhanced late blight management strategies.
The Potato Late Blight Caused by &lt;i&gt;Phytophthora infestans&lt;/i&gt; Mont de Bary as Selection Factor of Phurejas Potatoes (&lt;i&gt;Solanum phureja&lt;/i&gt; Juz et Buk) in Endemic Areas of the Bolivian Andes
(Scientific Research Publishing, 2013) M. Coca-Morante; Ismael Tolín-Tordoya
Phurejas potatoes (Solanum phureja Juz et Buk) are cultivated in very restricted areas of the Bolivian Andes. Late blight caused by Phytophthora infestans is a destructive, endemic disease that affects the survival and cultivation of this crop. The aim of this study was to determine the resistance characteristics of phurejas potato varieties to P. infestans in a traditional area of cultivation. An experimental plot was prepared in the locality of Chojchoni (3200 m) and planted with different phurejas varieties: 1) Chojllu Phureja (Sste); 2) Phureja Amarilla (Sphu); 3) Polo Phureja (Sphu); 4) Phureja Roja (Sphu); 5) Phureja Negra (Sphu) and 6) Waych’a Pacena (Sadg), a susceptible control. Severity was assessed according to the criteria of the Centro Internacional dela Papa, determining the area under the disease progress curve (AUDPC). Regression analysis (logN disease severity against time) was performed using the logistic model [ln(y/1 - y)] to determine infection rates. The different varieties showed different levels of resistance. The disease progress curve, the AUDPC and the linear regression results revealed the varieties Chojllu Phureja, Phureja Amarilla and Polo Phureja to likely have larger copy numbers of minor resistance genes against P. infestans than Phureja Roja or Phureja Negra. Late blight caused by P. infestans could cause the long-term loss of some phurejas varieties through farmers selecting others less severely affected by the disease.