The effects of weevil on water hyacinth control
varied from one place to another. Four sites in Wen-
zhou City of Zhejiang Province were selected for the
experiments by CAAS (China Academe of Agricul-
tural Science) in 1996. A release of 1000 in-
sects/(1000 m2
) in two sites exerted an efficacy
around 90% of the water hyacinth infestation for the