Avalia??o da deposi??o de calda em anteras de trigo, para o estudo do controle químico de giberela (Gibberella zeae)

摘要

The head blight caused by the fungus Gibberella zeae (Fusarium graminearum) is a major floral disease of wheat. The chemical control is efficient only if the fungicides are applied at the full anthesis to protect anthers. In this research, the main objective was to built such a spray boom to allow different spray nozzles arrangements. The anther staining provided by color dyes applied with different spray nozzles, nozzle arrangements, and spray volumes was also assessed. Two spray booms were used, one with individual nozzles spaced at 0.50 m and another one mounted with adjustable sets, also spaced at 0.50 m, each one having one nozzle forward (30o or 45o) and the other backward at an angle of 30o or 45o. The nozzle types used were flat fan, twin flat fan, and hollow cone. A total of four experiments were carried out. The deposition of color dye was higher on loose than on trapped anthers. The double nozzle sets resulted in increased spray volumes (200 to 400 L ha-1) and higher numbers of fungicide sprayed anthers. The nozzle types did not differ from each other. The anther staining was improved by nozzles positioned at 45o (forward and backward) but not at 30o.