Tribenuron-Methyl Resistant Shepherd's Purse (Capsella bursa-pastoris (L.) Medik.) in Hebei Province of China

Shepherd's purse seeds were collected from winter wheat fields and road sides in Hebei Province, China. Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse. Results revealed that HB-1, HB-2, HB-3, HB-4, HB-6, HB-7, HB-17, HB-18, HB-19, HB-20, HB-21, and HB-22 populations were susceptible to tribenuronmethyl characterised by very low GR50 values of about 0.10 g a.i. ha-1. On the other hand, populations HB-15 and HB-16 had moderate resistance to tribenuron-methyl with resistance indices (RI) ranging from 10-100 folds, whilst populations HB-5, HB-8, HB-9, HB-10, HB-11, HB-12, HB-13, and HB-14 expressed high level of resistance to tribenuron-methyl with resistance indices over 100. The proportion of moderate resistance level was about 9.09%, and that of high resistance was about 36.36%.