Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Fitopatología

Esta investigación tuvo como objetivo la identificación del agente causal del mildiú de la albahaca y la validación de un método de estimación de la severidad. El patógeno presenta morfométricamente zoosporangióforos monopodiales y ramificados dicotómicamente en ángulo agudo hasta 4,25 veces en la parte terminal, un largo de 320,1 µm; esterigmas cortos de 15,5 µm y de 17,9 µm de largo. Los zoosporangios, ligeramente ovoides con 27,7 µm de diámetro y con 31,9 µm de largo. La estimación de severidad se realizó por el método de Horsfall y Barratt (HB) (Horsfall y Barratt, 1945), por estimación visual directa (VD) y evaluando daño foliar por cada tercio de la planta (TH). La evaluación aleatoria se realizó en tres oportunidades por tres evaluadores, y los valores estimados fueron correlacionados con la severidad real. Para medir la confiabilidad entre evaluadores y mÃ...

The objective of this research was to evaluate the behavior of five commercial varieties of quinoa, naturally infected by P. variabilis. The study was carried out at the Universidad Nacional Agraria La Molina, Lima, Peru. The varieties studied were: Amarilla de Maranganí (AMR), Pasankalla (PAS), Negra Collana (NGR), Salcedo (SAL), and Altiplano (ALT). Treatments were distributed in a complete randomized block design with five repetitions. Variables evaluated include: yield (kg/ha), plant height (cm), disease severity using Area under Disease Progress Curve (AUDPC), protein content (%), weight of one thousand grains (g) and grain size (%). Comparisons of means were conducted using Tukey’s test, Pearson correlation coefficient analysis and statistical significance was set at p < 0,05. Results revealed statistics differences among treatments. The AMR variety had the highest yield (262...

Custard apple (Annona cherimola Mill.), originally from the Andean region of Peru and Ecuador, faces a serious threat from root rot, a disease that significantly reduces its yield. In 2015, root damage caused by Dactylonectria macrodidyma was reported in Chile, while Pythium splendens was identified as the root rot culprit in the Annona genus in Australia and Florida. This study aimed to identify the causal agent of custard apple root rot in Peru using PCR. In 2014, twelve ‘Cumbe’ custard apple plants from commercial fields in Ancash and Lima, Peru, displaying symptoms like yellowing leaves and dieback, were examined. The molecular identification was performed through specific rDNA regions (ITS and Cox II) amplification using primers ITS6/ITS4 and FM66/FM58 and revealed the presence of Globisporangium splendens (previously Pythium splendens), which had not previously been recorded as...

The flowers blight caused by Botrytis cinerea Pers. is among the most important citrus diseases, especially in cultivars whose flowering coincides with the humid seasons of the year. As a result of the pathogenic features of this fungus and the complex nature of its control, it is necessary to establish a correct plan for the usage of highly efficient fungicides. The study aimed to evaluate the effect of four chemical fungicides, such as Captan (0.25%), Propineb (0.25%), Fludioxonil + Cyprodinil (0.05%), and Iprodione (0.15%); as well as the effect of a biological fungicide, such as Melaleuca alternifolia extract (0.1%), on Botrytis cinerea Pers. Two phases were established: the first, under laboratory conditions of Department of Plant Pathology of National Agrarian University-La Molina (UNALM), evaluated the effect on mycelial inhibition at 1, 3, and 7 days after inoculation with poison...