Volunteer Kentucky Bluegrass(Poa pratensis)Control in Kentucky Bluegrass Seed Fields

The carbon banding technique was evaluated for control of volunteer Kentucky bluegrass(Poa pratensisL.) while Kentucky bluegrass was established for seed production. At Madras, Oregon, where terbacil (3-tert-butyl-5-chloro-6-methyluracil), diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] were applied at several rates each, volunteer Kentucky bluegrass control between the carbon bands ranged from 80 to 99+%. At Corvallis, Oregon, where Colonial bentgrass(Agrostis tenuisSibth. ‘Highland’), red fescue(Festuca rubraL. ‘Pennlawn’), perennial ryegrass(Lolium perenneL. ‘NK-100’), and orchardgrass(Dactylis glomerataL. ‘S-143’) were planted to allow identification of volunteer Kentucky bluegrass both between and in the carbon bands, diuron, atrazine, and a combination of diuron and terbacil eliminated volunteer Kentucky bluegrass. Terbacil did not control all Kentucky bluegrass between the bands. None of the herbicide treatments adversely affected crop establishment or seed yield.