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Fitopatologia Brasileira

Print version ISSN 0100-4158

Abstract

ALVES, Marcelo C. et al. Geoestatistics as methodology to study the space-time dynamics of diseases transmitted by seed-borne Colletotrichum spp.. Fitopatol. bras. [online]. 2006, vol.31, n.6, pp. 557-563. ISSN 0100-4158.  http://dx.doi.org/10.1590/S0100-41582006000600004.

The aim of this work was the characterization of the space-time severity progress of the common bean Anthracnose and cotton Ramulose through Geoestatistics. The experiments were conducted over different periods during the rainy season, in field conditions. Seeds inoculated by the water restriction method were sowed in the center of experimental plots standing as inoculum source of point type. Six evaluations of the epidemics’ severity were done weekly following disease diagrams. The clustered pattern and the spatial dependence in both pathosystems were verified with isotropic spherical and gaussian semivariogram models adjusted to the data. With the ordinary block kriging method, it was possible to verify that the severity of the diseases was lower in the first stages, becoming higher over time in both epidemics. Anthracnose presented initially secondary inoculum focus formation besides the focus with initial inoculum with later coalescence. The severity of Ramulose decreased gradually, both radially and smoothly from the center of the plot to the borders, with a larger capacity to infect neighboring plants, when compared to the Anthracnose, possibly due to the fungi’s aggressiveness and to the cotton plant’s shrubby growth habit.

Keywords : Colletotrichum lindemuthianum; Colletotrichum gossypii var. cephalosporioides; ordinary kriging.

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