Keeping residues low enhances wool’s reputation as a pure and natural fibre and enables access to residue-sensitive markets. Most chemical residues are found in the wool grease and not on the wool fibre but there is a growing demand for low-residue wool because of issues with wool scouring effluent. European Union (EU) pollution control legislation which comes into effect in 2007 will place strict limits on emissions from wool scours and will require that European wool processors source wool low in chemical residues. Some processors in China are now also beginning to measure residue levels.

Pesticide residues in wool come mainly from lice and flystrike treatments. The highest residue levels generally result from long wool treatments or incorrect chemical use, but some post-shearing treatments can also leave high residues. Strategies such as treating only when lice are detected, avoiding long wool treatments where possible and choosing chemicals which break down rapidly, will help keep residue levels low. The WoolRes module in LiceBoss allows you to calculate the residues expected from use of any registered treatment.

For more information about wool residues see Wool residues - issues and Guidelines for preparing low residue wool.