Non-target organisms programme

The potential effect of Bti-based mosquito control on non-target organisms is monitored by our follow-up programme , with focus on the non-biting midges (chironomids). Chironomids are an important food source for birds and bats, and are sensitive to Bti although at a higher dosages than mosquitoes.

The non-target follow-up programme is performed in 12 wet meadows, at the fringe of Lake Färnebofjärden, in the River Dalälven floodplain. Six study areas are designated “experiment areas” where floodwater mosquito control with VectoBac G is performed when required, and 6 study areas are “reference areas” without mosquito control.

Each study area has 10 emergence traps in continuous operation from May until September, with captured insects collected each week. Emergence traps catch all insects that hatch underneath the cone and occassionally fly up to the top where they are collected in a special container. The traps are put on the ground, but can float and will continue catching insects when the water rises in the study areas. The captured insects are sorted to insect order and for some groups further to family and subfamily level.

In addition, environmental variables such as water depth and air temperature are assessed. If there is a flood, water samples are taken for analysis of nutrient status of each study area.

Long term studies on the effect of VectoBac G treatments on non-target organisms in the River Dalälven floodplains commenced in 2002, with a wide focus on both direct and indirect effects. The results of the first six years of studies did not show any significant negative effects as reported in scientific journals READ MORE», and in one PhD thesis at Uppsala University READ MORE».

The current follow-up programme commenced in 2012, after suggestions by the Swedish Agricultural University (SLU) and discussions with authorities during 2011. The new programme is suggested to have higher resolution than the previous, and is included as mandatory in the mosquito control permit issued by the Swedish Environmental Protection Agency.

Map (2023)
Map showing our 12 study areas, 6 reference areas (green rectangles) and 6 experiment areas (blue triangles)
Emergence trap (with logo)
Emergence trap with temperature logger