SINTOMATOLOGIA E ETIOLOGIA DE Phyllachora sp. INCIDENTE EM FOLHAS DE GRAMA-BATATAIS (Paspalum notatum)

Abstract

Plant diseases play a crucial role in agriculture, affecting the productivity and quality of crops. This work focused on investigating the symptoms and etiology of Phyllachora paspalicola, a fungus found on the leaves of the potato grass (Paspalum notatum - Poaceae). Potato grass is a plant that adapts well to equatorial, tropical and subtropical climates, but faces plant health challenges. In this plant species, 329 records were found of the occurrence of 29 species of Phyllachora sp. as causative agents of black scab in species of Panicum spp. To carry out the analysis, we collected leaf samples in April 2019, which were examined and analyzed with the aid of a stereoscopic microscope. In addition, semi-permanent slides were prepared with lactophenol (cotton blue), using the techniques of direct fishing and histological sectioning for microscopic recording. The morphology and morphometry of the macro and microscopic structures was carried out for identification and comparison with the literature. Symptoms: blackish dots of chlorotic halos were observed, distributed throughout the tissue; when young, the lesions and/or crusts were 300-500 mm in diameter, progressing to yellowing, ending in grayish necrosis; confluent crusts covering a large area of plant tissue were not observed. Signals: The asca were cylindrical, subclavate, obtuse, eight ascospores per asca, paraphysed, their dimensions were 116.56-(83.2)-63.18 x 11.72- (8.0)-3.69 micra; the ascospores were hyaline, unicellular, ellipsoid and their dimensions were 16.3-(12.96)- 9.44 x 8.58-(5.87)-2.92 micra. This is the first record of P. paspalicola occurring on potato grass leaves in the city of Urutaí (GO).