Abstract

Four experiments were conducted to evaluate the tolerance of three landscape crops to over the top spray applications of diuron. Rates ≥ 0.56 kg ai/ha (0.5 lb ai/A) provided excellent (100%) yellow woodsorrel control regardless of the time of year the treatment was made. Diuron applications ≤ 1.12 kg ai/ha (1.0 lb ai/A) in fall and spring caused slight to no injury to dormant abelia, barberry, and spirea. Plants leafed out normally in the spring after application and there was no difference in growth 180 days after treatment (DAT). Application at 2.24 kg ai/ha (2.0 lb ai/A) caused slight to no injury on abelia, moderate injury to spirea, and severe injury to barberry by the following spring. Spring application to actively growing abelia and spirea caused slight to moderate injury from which plants treated with ≤ 0.56 kg ai/ha (0.5 lb ai/A) completely recovered by 90 DAT. Abelia treated with 1.12 kg ai/ha (1.0 lb ai/A) were slightly injured 90 DAT, and spirea were moderately injured 90 DAT. Abelia and spirea treated with 2.24 kg ai/ha (2.0 lb ai/A) were severely injured with many dead plants 60 DAT. Actively growing barberry treated with 0.28 kg ai/ha (0.25 lb ai/A) remained moderately injured by 90 DAT. Rates ≥ 0.56 kg ai/ha (0.5 lb ai/A) caused death to actively growing barberry by 60 DAT.