Caracterización Molecular de la Diversidad Fúngica de los Bosques Llucud y Palictahua: Potencialidades en Control Biológico/Molecular Characterization of Diversity Fungic of the Llucud and Palictahua Forests: Potential in Biological Control

Dentro de los microorganismos más abundantes que se pueden encontrar en formaciones ecosistémicas naturales como los bosques andinos del Ecuador se encuentran los hongos microscópicos, los cuales desempeñan funciones cruciales en dichos ecosistemas. Por lo cual el objetivo de esta investigación fue caracterizar molecularmente la diversidad de hongos presentes en los bosques nativos Llucud y Palictahua, estableciendo sus potencialidades de uso en el control biológico de plagas y enfermedades que afectan a los cultivos agrícolas y cuyo control en su mayoría se lo realiza con plaguicidas químicos. Mediante secuenciación de próxima generación (NGS por sus siglas en inglés) de las muestras compuestas de suelo tomadas del horizonte “A” (rizósfera) de cada bosque, se identificaron 56 especies de hongos en Palictahua y 38 en Llucud, presentándose en ambos bosques un total de 6 hongos con importantes potencialidades para su uso en el control biológico, dentro de las cuales se encontraron: Brachyphoris oviparasitica (nematófago), Simplicillium (entomopatógeno y micoparásito), Hamamotoa lignophila (levadura con actividad Killer) en Llucud, y Metarhizium robertsii (entomopatógeno), Brachyphoris oviparasitica (nematófago) y Paraphaeosphaeria parmeliae (micoparásito) en Palictahua. El Bosque Palictahua presentó mayor diversidad de hongos que el bosque Llucud, sin embargo es importante cuidar ambos bosques, pues poseen una gran riqueza microbiana con un sinnúmero de posibilidades de uso en la medicina, industria, biotecnología y otros campos. Among the most abundant microorganisms that can be found in natural ecosystem formations such as the Andean forests of Ecuador are microscopic fungi, which play crucial roles in these ecosystems. So that the objective of this research was to molecularly characterize the diversity of fungi present in the native forests Llucud and Palictahua, establishing their potential for use in the biological control of pests and diseases that affect agricultural crops and whose control is mostly carried out with chemical pesticides. Through next-generation sequencing (NGS for its acronym in English) of compound samples of soil took from “A” horizon (rhizosphere). 56 species of fungi were identified in Palictahua and 38 in Llucud, presenting in both forests a total of 6 fungi with significant potential for use in biological control, among which were found: Brachyphoris oviparasitica (nematophagous), Simplicillium sp. (entomopathogen and mycoparasite), Hamamotoa lignophila (yeast with Killer activity) in Llucud, and Metarhizium robertsii (entomopathogen), Brachyphoris oviparasitica (nematophagous) and Paraphaeosphaeria parmeliae (mycoparasite) in Palictahua. The Palictahua forest presented greater diversity of fungi than the Llucud forest, however it is important to take care of both forests, since they have a great microbial richness with a myriad of possibilities of use in medicine, industry, biotechnology and other fields. Palabras clave: Biodiversidad, Microbiota, Plaguicidas. Keywords: Biodiversity, Microbiota, Pesticides

Pathogenicity of Entomopathogenic Fungi on the Weevil of the Andes (Premnotrypes vorax Hustache) of the Potato (Solanum tuberosum L.) in Chimborazo Province, Ecuador

From thirty native isolates of entomopathogenic fungi, which were obtained from corpses of larvae and adults of Andean weevil (Premnotrypes vorax Hustache); two fungi with entomopathogenic characteristics were selected through laboratory tests, which will be used in a program of integrated management of this pest in the Ecuadorian inter-Andean region. The pathogenicity of the 30 isolates was determined by the mortality that they caused in larvae and adults and it was expressed in percentage; for this, a complete randomized design (CRD) was used. The LC50 and TL50 were determined by Probit analysis. The two selected isolates corresponded to: Metarhizium anisopliae (Metschnikoff 1879) Sorokin 1883 (A13) and  Beauveria bassiana (Bals.-Criv.) Vuill. 1912 (A21), which proved to be the best, because they caused the highest mortality in larvae of the fourth instar and adults of P. vorax. The Probit analysis showed that LC50 for A21 isolate (B. bassiana) in fourth instar larvae was obtained with a concentration of 1,75x109 spores/ml and 1,08x109 spores/ml for adults. Instead for A13 isolate (M. anisopliae), the LC50 was obtained with a concentration of 1,65x109 spores/ml for larvae and 2,42x109 spores/ml for adults. The LT50 for the selected isolates at the indicated concentrations, was 4,84 and 4,32 days for larvae with A13 and A21 isolates respectively, while, for adults, the shortest time was obtained with A21 isolate in 4.36 days, compared with A13 isolate, that delayed 20,70 days. The larval stage of P. vorax was the most susceptible to A13 isolate, on the other hand, larvae and adults were equally susceptible to A21 isolate at the indicated concentrations. According to the results obtained, the two selected isolates can be used as an alternative to the use of conventional agrochemicals, which will contribute to a more ecological production

Evaluación de tres dosis de potasio en la producción de lechuga (Lactuca sativa L. var. Crispa) bajo el sistema hidropónico recirculante NTF bajo invernadero

Three doses of potassium were evaluated in the production of lettuce (Lactuca sativa L. var. Crispa), under the recirculable NFT hydroponic system in the greenhouse of the Department of Horticulture of the ESPOCH. A completely randomized block design was used with three treatments and three replications. The doses evaluated were: low dose (LD) with 224,33 ppm, medium dose (MD) with 470,00 ppm, and high dose (HD) with 716,67 ppm. Evaluated parameters were: potassium content in leaves and root, fresh weights of the aerial part and root, yield per net plot and hectare. The economic analysis was carried out according to the relation benefit/cost. The best results for most of the parameters evaluated were obtained with the low dose (LD), obtaining fresh weights of the aerial part and root of 193,01 and 36,65 g respectively. It has a yield per net plot of 2,04 kilograms and per hectare of 15338,75 kilograms, and the highest cost benefit with 4,63 dollars equivalent to 362,75%. On the other hand, the highest content of potassium in leaves and root up to 40 days after transplant (DAT) was obtained with the medium dose (MD) with 5,13 and 6,00% of total potassium, respectively. In all treatments, maintaining turgor in the plants throughout the cycle is very important. From the agronomic and economic point of view, the use a nutritive solution containing 224,33 ppm of potassium was recommended