Abstract

Ethanol production from sweet sorghum depends on the quality of the biomass and sugars in the juice extracted from the plant. However, quality may be compromised by Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) or sugarcane borer infestation. This study evaluated the effects of infestation by the pest on sweet sorghum juice productivity and quality. Sorghum variety BRS506 was planted in an experimental area with 4,800 m². Samples were harvested at 115 days after planting and the following variables were evaluated: physical injury caused by the pest in the stalk, juice yield, total soluble solids in the juice and chemical composition. Additionally, the presence of Fusarium sp. in the stalks was checked. A significant difference was detected for juice yield, with lower values found in bored stalks resulting in a 2.62% decrease in juice yield at an infestation intensity of 4.16%. Infestation of D. saccharalis also caused a reduction of 34% in the plant sucrose content and significantly decreased fiber, lignin and ash rates. Infestation by D. saccharalis in sweet sorghum caused a significant reduction of plant height, juice productivity, and was associated with the presence of Fusarium sp., and sugar and fiber reduction.

Key words: Chemical composition, integrated pest management, juice quality, sugarcane borer.