Study on the occurrence pattern of Eichhornia crassipes in Changde

Scince Eichhornia crassipes has been a disaster in southern China, its occurrence pattern in Chuanzihe River was studied for finding the reasonable and economical control techniques. The result indicated that the main biomass was got from June to mid September and affected by the climate and water conditions, it was also affected by the water pollution level because its biomass in heavily polluted Chuanzihe River was higher than that in lightly polluted pools.