Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Rates of terbuthylazine and its mixtures with terbumeton for weed control in poplar and willow nurseries.

Abstract

Field trials were conducted with Populus deltoides × nigra (= × canadensis) Veronese, P. × canadensis × yunnanensis NZ5007, Salix matsudana × alba Tangoio and shrub willow [Salix] Irette purple osier, planted on 22-23 Aug. 1989 on loamy sand at Aokautere, New Zealand. The 4 clones were sprayed on 18 Sep. 1989 with 2-8 kg/ha terbuthylazine alone or with 1:1 or 2:1 mixtures of terbuthylazine:terbumeton at terbuthylazine rates of 1-12 kg. Weed control was, in general, good with all herbicide treatments and was very good at the higher rates. However, Digitaria sanguinalis and Cirsium arvense were not well controlled. Damage, assessed 32 d after treatment, was rated on the Shaw and Swanson scale (where 0 = none and 10 = all) as 3-5 to Irette and slight (≤3) to the other 3 clones. NZ5007 was significantly less affected than the others. Injury was significantly greater as the application rate increased but was never rated >5. Terbumeton caused little, if any, additional damage to that resulting from terbuthylazine application. Fitted cubic curves predicted an optimum use rate of 1.4 kg terbuthylazine.