Management of problematic aquatic weeds in Africa. FAO efforts and achievements during the period 1991-2001

agent de lutte biologique agentes de control biológico aguas interiores aquatic weeds biological control biological control agents case studies control biológico désherbage eaux continentales eichhornia crassipes escarda estudios de casos prácticos inland waters lutte biologique malezas acuáticas mauvaise herbe aquatique pistia salvinia molesta weed control étude de cas