TITLE:
Epidemiologic Study of Ramularia areola under Different Soil Covers and Spacings, for Cotton Crops
AUTHORS:
Jaqueline Aguilla Pizzato, Dejânia Vieira Araújo, Milson Evaldo Serafim, Kelly Lana Araújo, Rivanildo Dallacort, Thiago Alexandre Santana Gílio, Jair Romano Júnior, Vanderlei Antunes Maciel
KEYWORDS:
Pennisetum glaucum; Crotalaria spectabilis; Areolate Mildew; High-Density Crops and No-Till
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.11,
November
13,
2013
ABSTRACT: The objective
of this work was to evaluate the progress of the areolate mildew of cotton
under different soil cover and spacing conditions. The experiment was carried
out using randomized blocks and a 2 × 3 factorial design, with
two spacings (0.45 m and 0.90 m) and three soil covers (no cover, Pennisetum glaucum and Crotalaria spectabilis) with four
replications. The plants were inoculated with R. areola, sixty DAS. A total of 14 evaluations of disease severity
were performed. At the lower, middle and upper thirds of plants, a diagram
scale with nine levels of severity was used and the resulting data
were converted into the AUDPC. Gompertz, logistic, and monomolecular
mathematical models were tested in the disease severity curves for each third.
Agronomics characteristics were evaluated as well. Significant differences of
AUDPC were found for the cotton plants thirds, and the middle third was the
highest AUDPC. Significant difference for the lower and upper thirds, whose
AUDPC were highest on 0.90 m spacing, was observed too. The disease
progress curves of the thirds did not fit the tested models. Significant results
to the both covers situations, where the treatments grown on crotalária cover
and without cover had highest AUDPC, were evidenced. The treatments with C. spectabilis cover were taller than
other treatments. Significant data were observed for the cover crops used and
in the treatments grown at 0.90 m spacing, to residual cover and crop
yield, respectively.