Control of Culex pipiens fatigans(W) by the larvivorous fish Poecillia reticulata and by removal of debris from the breeding habitat.

Twice weekly removal of floating debris from two polluted ponds in Bangkok resulted in 75% reduction of immature populations of C.p. fatigans for seven weeks. Subsequent introduction of the guppy Poecilia reticulata at 10 fish per m2 further reduced the aquatic population to 2% of the pretreatment level during 12 weeks. When debris removal was discontinued, partial recovery of the larval density was observed. When fish were introduced in a plot without prior debris removal, there was no reduction of the mosquito population, and when only part of the debris was removed from one plot, the reduction was immediate.