IDENTIFICAÇÃO, MORFOMETRIA E MORFOLOGIA DA FERRUGEM DA ERVA-GROSSA (elephantopus mollis-asteraceae)

Abstract

The thick weed (Elephantopus mollis) is an important weed in agricultural fields and has uses in home medicine. Coarse grass rust provides information on the survival of the initial inoculum in off-season periods, allowing linkage of hostability with commercial asteraceae and/or ability as a bioherbicide. The objective of this work was to characterize morphologically and morphometrically the rust caused by Coleosporium elephantopodis. Samples of blackthorn leaves showing rust symptoms from Urutaí (17° 29 08 S 48 12 47 O) and Hidrolândia (17° 0 56 S 49 12 2 O), Goiás, were analyzed in the laboratory. Macroscopic recordings of the symptoms and microscopic (stereoscope and optical) recordings were made of the signs. Semi-permanent slides were prepared for morphological and morphometric analysis of reproductive structures (uredinial cycle) using direct fishing and histological sectioning techniques. The symptoms of pustules are more abundant in the abaxial part of the leaf, however, amphigenous, and located both on the veins and on the leaf blade. It has a yellowish pulverulence, and may display a chlorotic halo with polygonal necrotic lesions on the adaxial surface. Urédia has dimensions of 151.1-(89.0) -36.0 x 100.1-(47.4) -20.0 m, in histological section it occupies an area of 7213.4-(3198.5) -246.92 m2; urediniospores catenulate, ovoid, cylindrical, oblong clavate, fringed, and their dimensions are 22.7-(18.2) -12.3 x 17.8-(14.4) -9.7 m. based on morphological and morphometric characteristics, isolates from both localities were identified as C. elephantopodis.