Charcoal Rot on Cotton in Ecuador: Symptoms, Etiology and Management with Seaweeds
Charcoal Rot on Cotton in Ecuador: Symptoms, Etiology and Management with Seaweeds
Frank G. Cedeño-Lozano1, Freddy Zambrano-Gavilanes2 and Felipe R. Garcés-Fiallos3*
ABSTRACT
In this work, the effect of commercial algal extracts was examined based on Ascophyllum nodosum, Sargassum spp., and Spirulina spp. on the incidence of dead plants (%), Area Under the Disease Progress Curve (AUDPC) concerning that variable, severity (%) of rot in roots and hypocotyls, and vascular necrosis in hypocotyls (%) associated with charcoal rot, and the chlorophyll index (SPAD) in cotton plants (Gossypium hirsutum L.) varieties DP ALCALA 90 and COCKER 310 established under field conditions. Under semi-controlled conditions, emergence (%) and damping-off (%) were evaluated in seedlings of the two genotypes grown in soil where the field experiment was carried out and another obtained from a distant place where no agricultural activity was carried out. Under the same conditions, the size of microsclerotia (n=20) and pathogenicity of two Macrophomina isolates on COCKER seedlings were determined. After the data were subjected to a two-way ANOVA, the Tukey test separated the means (P ≤ 0.05). All the plants analyzed presented charcoal rot and presence of microsclerotia, mainly in hypocotyls. Only vascular damage in hypocotyls was higher in COCKER 310 plants compared to those of the other genotype. A significant interaction between varieties and algal extracts was found for dead plants incidence (P ≤ 0.0305). Seedling emergence (%) was higher in COCKER 310 seedlings grown in infested soil compared to those of the other genotype (P ≤ 0.0276). To our knowledge, this is the first report of Macrophomina phaseolina on cotton in Ecuador.
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November 2023
Vol. 39, Sp. Iss. 2
