Evaluation of flazasulfuron for hair fescue (Festuca filiformis) suppression and wild blueberry (Vaccinium angustifoliumAit.) tolerance

Abstract

Flazasulfuron was evaluated for crop safety and efficacy on hair fescue (Festuca filiformis Pourr.) in wild blueberry (Vaccinium angustifolium Ait.) fields. Treatments consisted of flazasulfuron applied at 38 and 50 g a.i. ha−1in fall of the bearing year and spring and fall of the non-bearing year. Industry standard fall bearing year pronamide (2240 g a.i. ha−1) and spring non-bearing year terbacil (2000 g a.i. ha−1) and foramsulfuron (35 g a.i. ha−1) applications were included for comparison. Pronamide consistently reduced flowering hair fescue tuft density in the non-bearing and bearing years across sites. Terbacil reduced flowering tuft inflorescence height in the non-bearing year, but did not reduce total or flowering tuft density in either year. Foramsulfuron reduced flowering tuft density and flowering tuft inflorescence number and height in the non-bearing year, but hair fescue recovered in the bearing year. Fall bearing year flazasulfuron applications did not reduce total or flowering tuft density or flowering tuft inflorescence number and height. In contrast, spring non-bearing year flazasulfuron applications reduced flowering tuft density and flowering tuft inflorescence number and height, though hair fescue recovered in these treatments in the bearing year. Fall non-bearing year flazasulfuron applications reduced hair fescue total tuft density, flowering tuft density, and flowering tuft inflorescence number in the bearing year. No treatments caused significant injury to wild blueberry. Flazasulfuron may contribute to improved hair fescue management in wild blueberry, and this herbicide should be evaluated further to confirm crop tolerance and identify potential use patterns with currently registered herbicides.