Game Cover Crops

Game Cover advice for farmers in NorfolkChemspec agronomists have had many years of experience in advising on game cover crop mixtures and their agronomy requirements. Using our extensive data base we can recommend herbicide options for very complicated game cover mixes.

 

 

Flexible approach to early weed control in maize

Keeping weed competition to a minimum during establishment is key for any crop, but none more so than maize.

Yields can be hit dramatically by weed competition during the first six to eight weeks of growth, so whether it’s destined for forage, biogas, or grain, maize growers need to use a flexible and robust pre-emergence herbicide to give the crop the best possible chance, say experts.

“If you allow any weeds to compete with the crop at this early stage, growth will be more backward, yields will be reduced significantly and crop maturity will be delayed,” says BASF technical services advisor, Iain Ford.

He points to trials which have shown that the yield impact increases rapidly as weed control is delayed past early post-crop emergence. For example, controlling weeds by the 2 leaf stage of the crop resulted in a yield of 14 t DM/ha in the trials, while leaving crops weedy until 8 leaves reduced yields by 11%.

Mr Ford says Wing-P (dimethenamid‑p + pendimethalin) controls a wide range of weed species, has good residual activity which keeps weeds at bay for longer and offers growers timing flexibility in the event of catchy spring weather.

With more maize growers using contractors to spray crops and increasingly volatile weather, this flexibility could be vital, as herbicides may not necessarily go on in optimal conditions or contractors may have to come back at a later date.

Wing-P can be applied both pre-emergence and post-emergence of the crop from 1 leaf to 4 leaves (GS 10 to 14), and gives good residual activity against weeds throughout the establishment period and beyond, says Mr Ford. “The full rate [4 litres/ha] gives best persistency and, given sufficient soil moisture, can give good weed control until well past the time that crops meet across the rows.

“Weeds such as Black Nightshade, Orache and Fat Hen will germinate repeatedly throughout the season, so you need that residual activity to control each flush of weeds otherwise a programme of follow-up sprays will be needed.”

He acknowledges some growers may be reluctant to go on with a pre-emergence herbicide when seedbeds are dry, but says the dimethenamid in Wing-P gives it greater efficacy in drier conditions than straight pendimethalin. It’s efficacy against a wide spectrum of weeds also removes the need for tank mixing different products, he adds.

Chemspec agronomist Peter Pointen used Wing-P on 300 acres of forage maize in East Anglia last year and was “really pleased” with how it performed. “It is definitely a step on from straight pendimethalin and worked really well for us. We typically went on with half to three-quarter rate pre-emergence of the crop in mid-May and some fields didn’t need anything else. If I’d got half the level of control as last year, it still would have been worth doing.

“Maize is so susceptible to weed competition in the early stages and once the crop gets to eight leaves growers haven’t got many weed control options, so pre-/ early post-emergence herbicides are an essential management tool.”

While any pre-emergence herbicide needs a certain level of soil moisture for maximum control, he says Wing-P does offer greater flexibility in the event of exceptionally dry weather. “If the forecast is very dry, at least you have the option of being able to hold off application until there’s more moisture available. Pendimethalin is not very soluble in water, so once you’ve got the moisture there, you will get the persistency of control.”

Principle maize weeds

  • Blackgrass
  • Redshank (especially in crops grown under plastic)
  • Bindweed
  • Black Nightshade
  • Orache
  • Fat Hen
  • Knotgrass
  • Groundsel

Wing-P benefits;

  • Broad spectrum weed control
  • Flexible application window:
    • Helps avoid possible herbicide damage to crop
    • Weather delays are less critical
    • Potentially gives growers more time for seedbed preparationWide weed spectrum reduces need for tank mixes
  • Complimentary actives give good residual and immediate control
  • DMTA‑P is new to the UK maize herbicide market