Infestação de Diatraea spp. (LEPIDOPTERA: CRAMBIDAE) em variedades RB (República do Brasil) de cana-de-açúcar

Abstract

The aim of this study was to evaluate the variation of infestation Diatraea spp. in different varieties RB (Republic of Brazil) of cane sugar in cropping systems for dryland and irrigated four and three years, respectively. The varieties studied were as follows: RB72454, RB867515, RB971755, RB951541, RB931003, RB92579, RB863129 and RB93509. For the irrigated system, the variety RB98710 was also included. Assessments of the percentage of intensity of internal damage were carried out at harvest, in 15 stalks in each plot. All stalks were opened longitudinally, thus obtaining the percentage of internodes damaged by the complex borer/rottenness. The results were submitted to analysis of variance and means were compared by Tukey test at 5% probability. In the first year of assessment, in rainfed crop, the variety RB971755 showed the highest average of infestation by Diatraea spp. when compared with all other varieties. In the second year the variety RB931003 was the most attacked by the pest and for the subsequent two years the varieties did not differ in relation to pest attack. In the first year, for the irrigated system, the most infested variety was RB867515. In the following two years it was not possible to identify a variety with striking characteristic of preference by the sugar cane borer. In both systems, there was a decrease in crop productivity during annual assessment. The values of % infestation showed no significant correlations with the agroindustrial parameters evaluated in the two systems of cultivation.