Spring grass weed control in winter wheatwill be driven largely by drilling date in autumn 2013, as two distinctscenarios emerge – those who drilled before the weather broke in mid-October,and those who drilled later, into December.
Each scenario calls for a very differentcontrol strategy, with priority being given to those later-drilled crops.
John Cussans, Weed Biology Specialist forNIAB TAG said: Getting a residual on now is crucial in these later drilledcrops dont wait for temperatures to rise. Once active growth begins, thefocus should switch to applying a contact product as soon as possible.
Many later-drilled crops went in tosub-optimal seed beds and in the rush to get finished there was little time toemploy grass weed control measures. Action is now vital; graminicides offeringboth contact activity and a strong residual element will be key to achievinggood results, said Stuart.
Where blackgrass is the primary threat, DowAgroSciences recommends UNITE (pyroxsulam + flupysulfuron-methyl) with afurther residual treatment, preferably 120g ai/ha flufenacet and consideradding pendimethalin to the mix as well. This approach will control grass weedspresent, and any that emerge later. UNITE offers the added benefit ofcontrolling the widest spectrum of broad-leaved weeds, including volunteerbeans and cranesbill, and providing flexibility in post-harvest cultivationswhere oilseed rape will follow wheat in the rotation.
Where bromes, wild oats or rygrasses are thekey problem grass weeds, Broadway Star (pyroxsulam + florasulam) isrecommended, which offers the additional benefit of controlling an extensivespectrum of broad-leaved weeds.
Earlier is better, when it comes to grassweed control this spring, says Stuart. Its a very different season to spring2013 where growth stalled for months. To save time and money, both UNITE andBroadway Star having an extensive range of supported tank mix compatibilities,including many T0 and T1 products.
For those crops drilled earlier in autumn2013 its a very different story. Seed went into mainly good soils and staleseed beds and the dry weather also allowed for a programmed approach with aresidual pre-emergence followed by a post-emergence application. However, thereis no room for complacency and spring applications may still be required.
If a post-emergence application was missed,it will be vital to apply a contact product such as UNITE, as soon as growth recommences.Despite the relatively mild winter, there is still time to target blackgrassuntil it reaches growth stage (GS) 24. To extend control over any lategermination, adding a residual with a different mode of action from thatapplied in the autumn, will be of benefit. These treatments can be timed tocoincide with T0 applications.
Broadway Star will similarly provideeffective control of bromes and other grass weeds, along with a range of broadleaved weeds. Applying to weeds that are small and actively growing ispreferable, but Broadway Star is still recommended up to the following growthstages: Ryegrass up to GS29; Brome up to GS24; Wild oats up to GS29; Tame oatsup to GS24.