The present work aimed to evaluate the smallest concentration of the tracer fluorescent Poliglow 830 YLS necessary for an adequate contrast with the plant surface, as well as to develop a process for determination of spraying coverage using the software IDRISI for imagery analysis. Three doses of the fluorescent tracer Poliglow 830 YLS (5, 12.5 and 25 g) were previously mixed to 10 g of a mancozeb formulation, diluted in 5 L of water (0.001, 0.0025 e 0.005% w.v. of tracer) and applied on Hibiscus spp, with three different sizes of drops (very large, fine and very fine). After the complete drying of the carrier, samples of leaves were collected, taken to the laboratory and analyzed under ultra-violet light, where a leaf was visually selected with light, medium and heavy deposition, for each one of the nine treatments. The smallest dose of the tracer provided a quite incipient fluorescency for visual analysis, therefore being discarded. The other leaves were photographed with digital camera, in a totally dark atmosphere, under ultra-violet illumination. With these images, a routine analysis was developed in the software IDRISI, which allowed the automation of the coverage analyses. The software IDRISI showed to be an appropriate and efficient tool in the evaluation of the spraying coverage in the plant surface studied. The largest concentration of the tracer improved the sensitivity of the analysis.
spraying; distribution; imagery analysis; fluorescent tracer
