The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.
QUIK STATS (last updated Mar 06, 2004 )
NOTES ABOUT THIS BIOTYPE
Solymosi, P.; Nagy, P. 2000. Sulfonylurea resistance in Picris hieracioides L. Növényvédelem 2000 Vol. 36 No. 12 pp. 619-624 A keserűgyökér (Picris hieracioides L.) taxonómiailag is azonosítható szulfonilkarbamidellenálló biotípusának jellemzése.
We have found a sulfonylurea resistant Picris hieracioides biotype in Russia. This is a new case of sulfonylurea resistance. The degree of resistance varies with the biotype and herbicide. For chlorsulfuron, triasulfuron, tribenuron-methyl and amidosulfuron, the herbicide concentration required to reduce enzyme activity 50% (I50) was 6 to 22-fold greater using ALS [acetolactate synthase] isolated from the resistant biotype compared to ALS from the susceptible biotype. The imidazolinone herbicide imazapyr was less inhibitory (1.4-fold) to resistant P. hieracioides ALS. Lontrel 300 [clopyralid] (0.5 l/ha) and Mustang [florasulam + 2,4-D] (0.6 l/ha) herbicides were effective against the sulfonylurea resistant biotype of P. hieracioides.
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