Browsing by Author "Staier, TN"

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Can directed-spray strategies control Guinea Grass stools? : ASSCT peer-reviewed paper
(ASSCT, 2019) Fillols, E; Staier, TN
Guinea grass is a troublesome perennial grass in our sugarcane farming system. Despite a range of effective pre-emergent and early post-emergent herbicides, optimum spray windows are often missed and established Guinea grass stools are commonly found. To control established Guinea grass stools, growers often rely on spot spraying, which is time consuming and often requires multiple passes. Four replicated field trials were established to assess if directed-spray strategies could replace spot-spraying strategies. Field trials showed that a late application of isoxaflutole (75 g/ha) + MSMA (2.16 kg/ha) applied at the base of the row generated the strongest phytotoxicity symptoms on Guinea grass stools and reduced by up to 67% the number of Guinea grass stools in the following ratoon. However, this herbicide mixture also reduced sugarcane yield by 34-41% depending on the application technique. The safest treatment for sugarcane was an early banded spray with asulam (3.4 kg/ha), followed by a late interrow application of glyphosate (2.7 kg/ha) using a shielded sprayer, but the reduction in the number of Guinea grass in the following year was highly variable from trial to trial (0-67% reduction). No directed-spray strategies were identified to control established Guinea grass in sugarcane rows without a significant sugarcane-yield penalty.
Efficacy of alternative pre-emergent herbicides applied in trash-blanketed ratoons in the Wet Tropics
(ASSCT, 2016) Fillols, E; Staier, TN
As a result of continued exceedances in permissible pesticide levels in watercourses, the Australian sugar industry is under considerable environmental scrutiny, which has resulted in the restriction of use of products such as diuron.
Optimising spot spraying for controlling Guinea Grass : ASSCT peer-reviewed paper
(ASSCT, 2019) Staier, TN; Fillols, E
Established Guinea grass stools are commonly found in our sugarcane-farming system. No registered herbicides that are both effective on perennial Guinea grass stools and selective to sugarcane are available. Directed-spray strategies using registered herbicides and current spray configurations are not effective in controlling Guinea grass stools, so growers with Guinea grass escapes rely on spot spraying. To optimise spot spraying, the mixture applied needs to be effective in a single application with minimal impact on the adjacent sugarcane stools. Two pot trials screened herbicides registered in sugarcane for their efficacy to control established Guinea grass stools. The first pot trial showed that good spray coverage was crucial for successful control of Guinea grass spot sprayed with 1.35 L per 100 L of Weedmaster® Argo® (glyphosate 540 g/L) + 0.3 L of LI700* per 100 L. The second pot trial showed that isoxaflutole (75 g/ha) + MSMA (2.16 kg/ha) was the most effective herbicide combination and the application rate could potentially be reduced. Bobcat® i-MAXX (imazapic 25 g/L + hexazinone 125 g/L) was also effective when used at 2 L per 100 L, but Barrage® (diuron 468 g/kg + hexazinone 132 g/kg) was only effective when used at twice the recommended rate (2 L per 100 L) and only when the entire foliage was soaked to the point of runoff. The most effective spot-spraying options for Guinea grass control with the lowest impact on adjacent sugarcane were: isoxaflutole + MSMA, but this mixture is not registered for spot spraying application; and Bobcat® i-MAXX. Bobcat® i-MAXX SG (granular formulation), registered since 2018, includes a spot-spraying rate at 350 g per 100 L that is equivalent to the effective rate tested in the second pot trial.