PG Suspension

A biological control agent for Heterobasidion annosum (formerly known as Fomes annosus)

The Forestry Commission has a commitment to reducing chemical usage in forests in line with the aims of the United Kingdom Woodland AssuranceStandard (UKWAS). Although chemical stump treatment using urea is practised on many conifer species planted in the UK, a non-chemical alternative produced by Forest Researchis available for use on Pinus species, and has been used in Thetford forest in East Anglia for the past 30 years.

This biological control agent is called PG Suspension and the active ingredient is a wood-rotting saprophytic fungus, Phlebiopsis gigantea. This fungus does not attack living trees, but when applied to stumps prevents surrounding trees becoming infected with H. annosum by competing for resources on the stump surface.

It is currently only licensed for use on Pinus species in the UK.

Further information

• The biological control of conifer root and butt rot
• Forestry Commission pesticides pages
• PG Suspension product label with statutory conditions ^(PDF-1237K)
• PG Suspension for the control of Fomes Root Rot of pine
  Forestry Commission Information Note 18