Globally, corn is the most economically important crop, surpassing crops such as wheat, rice and barley. However, the presence of pathogenic fungi associated with corn, have favoured the appearance of diseases that cause economic loss. Therefore, the aim of the present study is to assess the efficacy of treatments in vitro and in vivo with Trichoderma asperellum in controlling the disease severity and the yield reduction in corn plants caused by Fusarium verticillioides and Ustilago maydis. In vitro confrontation experiments demonstrated the high antagonistic capacity of the T. asperellum strains, which is able to reduce the radial growth of the pathogen’s colonies from 88.71% up to 100%. In the field experiments treatments 6 and 7, where T. asperellum was confronted with F. verticillioides and U. maydis, showed a significant reduction in the average damage of the disease by 8.3 ± 6.7 and 9.5 ± 3.0, and an increase in their grain yield by 4.43 ± 0.33 and 4.11 ± 0.15 t/ha, respectively. Similarly, the percentage of good ears of 66.75 ± 5.4 and 70.37 ± 5.4, obtained in treatments 6 and 7, was higher than those values obtained in treatments 2 and 3 without Trichoderma confrontation. These results indicate that the selected Trichoderma strains isolated from Zea mays could effectively control these phytopathogenic fungi in field.
Scyphophorus acupunctatus Gyllenhal (Coleoptera: Dryophthoridae), which also is known as agave weevil, is distributed across 5 continents. In Mexico, their presence has been reported in 12 states. Many species of Agave (Asparagaceae) are suitable hosts, though not all are equally suitable. Plant infestation can start with either female or male weevils, and their presence can be detected by gummy secretions emanating from feeding sites. The punctures are observed principally in the lower part of the trunk and external roots of the infested plants. Eggs are deposited singly or in clusters of up to 4 eggs at the feeding punctures after tissue decay has begun. The eggs hatch after about 5 d, and young larvae begin to create tunnels in the plant tissue. The larvae display 11 instars, and require about 50 to 90 d for development. The pupae normally require 11 to 14 d. The life cycle lasts between 105 to 137 d depending on the agave species with which the weevil is associated. The active insect can attack during any mo of the yr, although it is more frequent in the rainy season. Scyphophorus acupunctatus dispersion is determined by the attraction of volatile agave compounds. This insect apparently introduces different microorganisms that have been associated with the agave maladies. Plant extracts and seed powders have been assessed as potential botanical insecticides on larvae and pupae, with plant extracts causing mortality of 43 to 53% in larvae and 3 to 15% in pupae, and with seed powders causing 90 to 100% larval mortality. Synthetic insecticides have not been successful because the larvae and adults live inside the plant tissues. Alternative effective control tactics are needed to avoid increased damage and destruction of this important crop.
Large quantities of seeds are generated and discarded during agro-industrial mango processing. However, mango seeds still contain valuable components such as starch, which has applications in various industries. This study aimed to obtain and characterize starches from the seeds of five mango cultivars (Ataulfo, Manililla, Piña, Tapana, and Tommy Atkins). The isolated starches were evaluated for their physicochemical, morphological, structural, thermal, and rheological characteristics. The starches showed creamy white colorations, and their granules had spherical and oval shapes. This starch source contains a high percentage of apparent amylose, greatly influencing its thermal, rheological, and functional properties. Structural and molecular studies showed that all starches presented an A-type X-ray diffraction pattern, impacting their water absorption and viscosity. The transition temperatures were relatively high, which could be influenced by the length of the amylopectin chains and their intermediate components, the apparent amylose content, and other components such as lipids and anomalous amylopectin. The starches evaluated behaved as pseudoplastic materials, while oscillatory tests revealed that the pastes formed with mango starches are more elastic than viscous. In conclusion, research on the seed starch properties of different mango cultivars provides interesting results for their potential application in foods. It could contribute to the value-added processing of mango seeds as a potential starch source.
Globally, corn is the most economically important crop, surpassing other cereals of economic importance. However, the tillage methods, monoculture and the abuse of synthetic agrochemicals used in Mexico have led to the loss of fertility and soil yield. In this sense, the application of alternative fertilization methods based on chemical fertilizer, organic matter and biofertilizer, applied alone or in combination, can stimulate the defense systems of corn plants and increase their yield. Therefore, in this research, some fertilization schemes were tested on purple corn plants of the Kculli race through the evaluation of some growth and yield variables, as well as the subsequent evaluation of the chemical characteristics of the corn grain produced in each fertilization scheme. The results indicate highly significant differences (p ≤ 0.05) between treatments, for the different growth and yield variables studied. Of all the fertilization schemes evaluated, treatment T7 obtained the best grain yield of 6.19 ± 0.07 t ha−1, with respect to treatment T1 of 1.02 ± 0.01 t ha−1, as well as the highest protein content and starch quality. Being clear the positive effect of the adequate contribution of the macro and micronutrients used exerts on the corn crop in each of the fertilization schemes studied. On the other hand, the analysis carried out on the grains was found within the values reported by other authors.
7 February 2019 in International Journal of Bio-resource and Stress Management
Introducción: Trypanosoma cruzi (T. cruzi), esta clasificado en seis linajes mediante marcadores moleculares de tipificación, que son fácilmente amplificados por técnicas de biología molecular. El objetivo del trabajo fue identificar y ubicar geográficamente a los aislados de T. cruzi que infectan naturalmente a los triatominas de los municipios del Estado de Hidalgo a través de la técnica de PCR, que amplifica fragmentos de la región intergénica del gen mini-exón. Método: Se recolectaron 170 muestras de insectos hematófagos en 14 municipios del Estado de Hidalgo, México. El diagnóstico de laboratorio en las muestras de heces y de tejido digestivo de los triatominos, se realizó de manera convencional por microscopia óptica y por la técnica de PCR para determinar la presencia o ausencia de T. cruzi y para la identificación del linaje correspondiente del parásito.Resultados: Se identificaron tres taxones de triatominos: Triatoma dimidiata (87/170), Triatoma mexicana (14/170) y Triatoma gerstaeckeri (7/170). En el 36.47% (62/170) de los especímenes colectados la especie no pudo ser identificada y se clasificaron únicamente como T. spp. Se determinó la presencia del parásito en el 1.76% de los vectores analizados por el método parasitoscópico y en el 11.17% por el método de biología molecular. El total de los parásitos analizados corresponde al biotipo TcI de T. cruzi. En el ecotopo peridoméstico, se encontró la mayor abundancia de triatominos (80.58%) y el mayor porcentaje (10.58%) de infección por T. cruzi.Conclusiones: El vector más importante encontrado en la región en estudio fue Triatoma dimidiata seguido de T. mexicana y T. gerstaekeri y el biotipo con el que están mayormente infectados es el TcI. Los triatominos encontrados se distribuían principalmente en hábitats peridomésticos en los municipios estudiados. Los resultados indican la existencia de riesgo de infección para los habitantes de esas regiones endémicas del Estado de Hidalgo, México.