Plant species attacked: Russian knapweed (Acroptilon repens); diffuse knapweed (Centaurea diffusa)
Damage to host: With permitable weather, this nematode can cause severe damage to the plant. The best incidence that supports this is the USSR

Releases:
First introduced into the United States: 1984, Washington
Now established in: Colorado, Montana, Oregon, Utah, Washington, & Wyoming (1)
Habitat: With enough moisture during the winter and spring infection periods S. picridis does very well. In dry areas S. picridis is less effective (1).
Availability: Limited