El coquito (Cyperus rotundus L.) en el cultivo de yuca: Interacciones y control

Recent information on the biological balance between purple nutsedge (Cyperus rotundus) and cassava is analyzed; the possibilities of influencing this balance to favor cassava are also studied. The slow initial growth of cassava highly favors the development and propagation of C. rotundus, resulting in competition between the 2 species during the 1st part of the cassava growth cycle. While competition for light may be of little importance, the allelopathic effect and the large consumption of water and nutrients by the weed may be responsible for cassava production losses. In cassava, mechanical control of C. rotundus continues to be the most common practice; however, this can aggravate the problem instead of reducing it. Only mechanical control during the dry season shows some promise. Preemergence herbicides or preplanting incorporated products currently used in cassava are of limited and erratic effectiveness against C. rotundus, but chemicals with improved effectiveness have been identified. In the area of postemergence herbicides, glyphosate continues to be the most effective. Since there is still no idealcontrol system, simple practice, or single herbicide to control and finally erradicate C. rotundus, investigation has focussed on integrated control measures that combine mechanical, chemical, and cultural practices. Future investigations will try to establish practical and economical integrated control systems and at the same time determine the factors responsible for yield and quality losses in cassava due to C. rotundus, such as allelopathy and competition for water and nutrients. (AS)