PROGRESS OF THE BEAN ANTHRACNOSE, WITH AND WITHOUT IRRIGATION, FROM FOCUS PLANTS

The anthracnose of the common bean, by Colletotrichum lindemuthianum, can severely compromise the grain yield of the crop. The dissemination of fungus internally in agriculture and the consequent infection is mediated by water spills that carry the spores at short distances. The present work was evaluated by the influence of temporal and spatial energy of the disease in a field, from plants in numerical source, in a plant arrangement of 200,000 pl / ha. In this way, the entire area was supplied with the irrigation system and daily execution at the end of the day, except on rainy days. In the irrigated area, an irrigation era was performed every two days and an area not irrigated, once produced once a week. From the disappearance of the leaves and petioles infected with disease, disinfested by specific techniques and by successive repetitions, the pure colony to stimulate sporulation in natural environment sterilized pod. The source of the inoculum was inoculated with control suspension, described above, adjusted with hemacytometer to a concentration of 1.2 x 10 6 spores / ml and inoculated with the aid of a spray bottle. See the viewing of the disease storms, in-scocular source plants arranged in the center of each plot (10x10meters) to assess disease progress from the point of view.It was observed a greater severity in the plants positioned at 0.5 m distance, reaching 12.25% in the irrigated condition and 0.75% in the non-irrigated area. As the distance from the source of inoculum was increased, the final severity under irrigation decreased to 6.25% (1.0 m), 5.00% (1.5 m), 4.00% (2, 0 m), 3.75% (2.5 m) and 2.25% (3.0 m). With these results it can be observed that in the evaluated period (35 days) the spatial evolution of the disease was 0.08 meters / day and highly dependent on the splash of water to reach a space of 3 meters in the crop. The prolonged and prolonged period of rainfall may have been the key to successful infection. In the non-irrigated area, the rainfall was 25% lower than the irrigated area, even though a period of leaf wetting was sufficient and satisfactory for the dissemination and development of the epidemic. The sharp gradients of infection of the plants from the inoculum source suggest the possibility of managing the disease by altering the arrangement of plants with larger spacing and / or smaller population.