Controle das brocas dos frutos no cultivo orgânico do tomateiro por meio de cobertura com manta de agrotêxtil

Abstract

Two fields plots dealing with organic farming tomato were conducted in Seropédica, state of Rio de Janeiro (Baixada Fluminense) along 2012 autumn-winter and spring-summer. In both experiments three management types were compared, as follows: (i) agrotextil (16 g m-2) permanent covering; (ii) agrotextil (16 g m-2) partial covering (from afternoon to next morning); and (iii) control treatment, without any covering. The study main purpose was to evaluate the protection of the crop by agrotextil as related to its ability to reduce the incidence levels of Helicoverpa zea and Neoleucinodes elegantalis, known as large and small tomato fruit borers, respectively. In the first experiment, the permanent (day and night) agrotextil covering was responsible for reducing in approximately 36% the proporcion of discarded fruits, comparing to the control. In the case of partial agrotextil covering such reduction reached 19%, but the treatment also was statistically significant relating to the uncovered experimented plots. In the treatment involving the agrotextil total protection the fruit setting by the UC-82 tomato cultivar was severely lowered (73,05%), again in comparison with the control treatment. On the other hand, the partial agrotextil covering surpassed the control in terms of marketable fruits. In the second experiment, the tomato crop faced very righ losses due to Corythaica cyathicollis (Hemiptera) that occurred all over the field regardless the treatments. Agrotextil covering either total or partial, had no interference in relation to the insect damage to the plants. This situation made entirely inviable to evaluate the agronomic parameters of the tomato crop as had been proposed. Results obtained in the first experiment indicated potential of the agrotextil use for partially covering dwarf tomato crop, under organic farming when carried out during the autumn-winter in the region.