California Pest Rating for Desert knapweed: Volutaria tubuliflora (Murb.) Sennen Family: Asteraceae Pest Rating: A | Seed Rating: R   PEST RATING PROFILE Initiating Event: This plant has been rated as “Q” on the CDFA Plant Pest Rating list for 2 years.  History & Status: The genus Volutaria comprises plants in the thistle tribe (Cardueae) of … Continue reading desert knapweed: Volutaria tubuliflora →