Tackling wild oats
The control of this vigorous weed – of which there are two species – is therefore a priority on infested land, with the prevention of seed production essential, especially as cultural controls such as later autumn drilling, spring cropping and ploughing are often less effective against wild oats due to the weed’s protracted emergence and ability to germinate from depths of up to 15cm.
Wild oats are one of the most competitive grass weeds with just one plant per square metre able to reduce winter cereal yields by as much as 1%.
A range of cultural and chemical control strategies must therefore be used, with hand rogueing essential in heavily infested crops. Weed mapping in June and or July (when the two species are more easily distinguishable) is also recommended as this will enable ensuing herbicide programmes to be tailored according to which species is prevalent.
Machinery hygiene is also required to limit the spread of wild oat seeds, with good levels of control seen where crops have been established by direct drilling or with minimal soil disturbance as this can help to reduce the germination of dormant seeds.
Herbicide best practice
When it comes to herbicide applications, sprayer operators are urged to be extra diligent when treating advanced crops as their dense canopy could prevent herbicides from reaching underlying wild oat plants.
An appropriate herbicide should be used to treat the worst affected areas prior to the shedding of seeds which typically commences from late June onwards: TOPIK (240 g/L clodinafop-propargyl and 60 g/L cloquintocet-mexyl) is approved for use in cereals, with FALCON (100g/L propaquizafop) the preferred option in broad-leaved crops. Axial Pro (55g/l pinoxaden) is also available for use in barley.
In all cases, these herbicides should be used with caution to ensure the required level of spray coverage and application accuracy: this means spraying slowly, at a sensible boom height, and with an appropriate water volume to optimise coverage of the target weeds.
For early spring herbicide applications (before GS31) it is feasible to reduce the water volume as the target weeds will be smaller and won’t be protected by the crop’s canopy. The inclusion of an adjuvant will enhance the efficacy of TOPIK at this early timing.
Later in the season (GS31-41), a greater water volume must be used to ensure good coverage of weeds hidden below the crop. At both timings, herbicide uptake will be aided if applied during good growing conditions, with a maximum forward operating speed of 12kph and a boom height of 50cm recommended. Nozzle choice will also have a significant effect on spray coverage. Improved control of wild oats is achieved when TOPIK® is applied at a reduced operating speed. (Photo credit: TOPIK® forward speed trial carried out by Syngenta)
Improved control of wild oats is achieved when Topik® is applied at a reduced operating speed.
(Photo credit: Topik® forward speed trial carried out by Syngenta)
The inclusion of non-cereal break crops into the rotation will also help in the battle against wild oats as this make it possible to use additional active ingredients such as propaquizafop, quizalofop, cycloxydim, clethodim and propyzamide.
For a detailed guide on how to distinguish between the two species of wild oats, and how to combat them effectively, please visit our wild oat information page here.