Nuisance chironomids in waste water stabilization ponds: monitoring and action threshold assessment based on public complaints.

Large populations of non-biting midges (Chironomidae) that emerged from waste water stabilization ponds in central Israel created severe nuisance to nearby residents in 1998. A study was begun in summer 1998 to examine the dynamics and phenology of the population as a basis for a successful control strategy. The extensive waste pond area required the development of efficient, reliable and competent sampling methods. The efficiency of four sampling methods was tested: (1) egg-mass counts, (2) larval counts, (3) adult emergence traps, and (4) sampling adults with yellow sticky traps placed on the shoreline. The latter two methods were significantly correlated with and accurately detected midge outbreaks. Yellow sticky traps were safer, easier and more convenient to employ for large scale monitoring. An action threshold was determined based on public complaints that were correlated with the numbers of midges caught by yellow sticky traps.