Assessment of Drift Exposure through Abrasion of Treated Seeds and Testing the Effects on Arthropods

To investigate the dust deposition during sowing of coated seeds or granule application with pneumatic or mechanical sowing machinery. Field studies are carried out following the draft Guideline SANCO/10553/2012 rev. 16 (2018).

We have been conducting dust deposition and dust filter trials since 2009, with a variety of machinery and crops within different countries.

Deposition trials collect dust (i.e. mechanical abrasion of the dressed seeds) emitted during seeding of dressed seeds or during granule application this is done with 2D and 3D sampling.

The deposition is collected using:

• Petri dishes filled with trapping fluid, horizontally arranged on the soil surface in certain distances to the seeding area (2D).
• Vertically erected and glycerol/water wetted gauze netting (3D).

Heubach test

The quality of the seed dressing needs to be assessed to determine if seeds are within commercial requirements. The Heubach method was developed for this purpose, it can be done in house by our phys-chem department.

Dust applicator

For risk assessment purposes, tests with realistic applications of defined amounts of dust might be needed, e.g. to determine NOEC or LOEC values. However, tests with dusts are much more difficult than tests with liquid substances. Due to the solid state and the varying particle size, it is challenging to develop standard ways of applying dust in situ and in vitro. In the field it is even more problematic to apply the low rates required.  

For this purpose we developed a application device to apply defined amounts of dusts to determine the effects of exposure on honeybees (Apis mellifera L.) or other non-target organisms.

A dust applicator was constructed specifically for ecotox trials. The application width is 3m - the principle of the application is the distribution of dust through high air pressure into the plant cover.