Period prior to interference of morning glory in sugarcane

Resumo

Sugarcane had great change in its production environment with the adoption of mechanized harvesting, highlighting the increasing importance of morning glory, for which there is no information about its interfer­ence in sugarcane cycle. The aim of this study was to determine the period prior to interference (PPI) of a weed community with predominance of Ipomoea hederifolia on sugarcane 'SP81-3250' in sugarcane plant cycle and its effect on technological parameters. Treatments consisted of increasing coexistence periods at the early of the cycle: 0, 0-15, 0-30, 0-45, 0-60, 0-75, 0-90, 0-120, 0-150, 0-180, 0-210, 0-270, 0-330 days after emergency. A randomized block design with four replications was used. Phytosociological analysis of weed community was performed, which confirmed morning glory dominance in the community and PPI obtained was 76 days after emergence, with a level of 5% of acceptable loss. The yield loss of industrialized stems due to morning glory interference was 17.5%. There was no change of sugarcane technological parameters.