![]() ![]() Simultaneously with this study, an informative manual for the management and culture of cycas was developed. To evaluate the severity of the symptoms in the two field experiments, a scale of 0-7 (0=no symptoms and 7=severe symptoms) was developed and validated at the beginning of the experiments. Results of this experiment indicate that the treatments did not have an effect in the severity of the symptoms of chasparria. In the other field experiment of phase three foliar fertilization using (Ca, Mg and Si as a management strategy for chasparria was tested). The acetic acid decreased the severity of the disease in the T2 and T3 but increase it in T1 treatment. It was determined that the conventional treatment is the best to manage chasparria in field conditions. One of them consisted in the evaluation of the rotation of conventional (T1) and non-conventional fungicides (T4) and the addition of acetic acid (50 ml L-1) (T2-T3). During the field trials, two experiments with experimental designs that consisted of five blocks and four treatments were conducted. Prochloraz, difenoconazole and pyrimethanil were the best of the systemic fungicides tested. Protectant fungicides, metiram, propineb and clorotalonil resulted in a highly percent of inhibition of the mycelial development. The active ingredient were categorized as high sensitivity 50 mgL-1 (clorotalonil, azoxistrobin, boscalid, mancozeb and mancozeb + oxicloruro de Cobre. Six concentrations of the active ingredient (0.01, 0, 0.1,1, 10, 100 ppm) of each fungicide were tested. proteae to fungicides (protectant and systemic) was tested. In another experiment the sensitivity in vitro of C. The leaves that were affected with more severity were those of phases V2 and V3. The disease presented an incubation period (IP) of three to five days on phases V1, V2, V3 and a latent period (LP) of six days for phase V4 the IP was seven days and LP nine days. proteae under experimental conditions were similar to those observed for chasparria in commercial farms. The disease symptoms were reproduced and the same fungus was isolated from infected tissues of all inoculated plants. The fungus was isolated from diseased tissues and inoculations to healthy plants were made. In the second stage, it was determined that the causal agent of chasparria was Colletotrichum proteae. Furthermore a photographic scale represented 12 phases of these foliar development was designed. These were designated as: Infant (V1), Formation (V2), Juvenile (V3) and Mature (V4). ![]() In the first stage the various phases of leaf development were determined. The investigation was divided in three stages. The following investigation was conducted with the objective of developing strategies to manage the foliar necrosis of cycas with plan knowledge and the study of the etiology of the disease. Por todo esto, sería conveniente incluir al Si entre los temas de investigación de los sistemas biológicos, para describir su participación en los procesos metabólicos. También, en animales se han reconocido las funciones del Si, principalmente en la formación de huesos y la respuesta inmune. Aunque se han encontrado evidencias genéticas de los posibles mecanismos de absorción y acumulación de Si, aún queda mucho por explorar acerca del papel bioquímico y fisiológico de este elemento en las plantas. El Si también les confiere resistencia al estrés biótico y abiótico. En ausencia de Si las plantas vasculares son más vulnerables a patógenos, insectos fitófagos y herbívoros. Esto se ha comprobado en algunos organismos unicelulares como las diatomeas, organismos marinos multicelulares como las esponjas, y en algunas plantas terrestres como las equisetáceas y otras de evidente interés para la humanidad como el arroz, caña de azúcar y calabaza. Dada su abundancia sobre la corteza terrestre y la suposición de que su concentración era aún mayor en el tiempo en que la vida hizo su aparición en la Tierra, es de esperarse que este elemento tenga algún papel en los organismos vivos. En los últimos años ha aumentado el interés por estudiar el papel del silicio (Si) en los organismos vivos en general. ![]()
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