Flexible contact herbicide provides a good start in potato crops – Potato News Today
UK potato growers can give crops a head start by changing the basis of their broadleaf weed control plans to Shark (carfentrazone-ethyl). But, as with diquat, timing is key.
Able to control weeds typical of a wide range of soils and potato growing regions, Shark is highly effective when used alone or in combination with other residual herbicides when applied just before crop emergence, says Jeff Fieldsend, Commercial Technical Manager at FMC Agro UK.
Timing is important
It is recommended to apply Shark at 5-10% emergence (5% emergence on early varieties and 10% emergence on main crop varieties), but operators should be careful with deadlines, warns Jeff.
“Although application at 5-10% emergence is attractive in terms of timing flexibility, it is best to use the product as soon as weed growth has developed and not risk applying too much. later crops are moving very fast at this time and late applications can hit them,” says Jeff Fieldsend.
Agronomist Rob Ramsey reports: “Shark has been a reliable diquat substitute for my customers, and we have seen good results with well-timed applications, with the crop coming back strongly even when 5-10% has emerged, there therefore has a fair application window, much like there was with diquat.
Trials by FMC and AHDB in the UK have proven that Shark is extremely safe for crops when applied at the right time. However, if application is delayed on potato plants more than 5-10% emerged, necrotic spots will occur which will disappear quickly and have no long term effect on vigor or yield.
Effective on a wide range of broadleaf weeds
“Shark is particularly effective on a wide range of broadleaf weeds including polygonum species, cleavers, annual nettles and speedwells up to the seedling stage when applied at a rate of 0 .33 L/ha, with excellent activity observed within 2-3 days of application,” adds Jeff.
“It is suitable for all varieties of potatoes and all types of crops, including seeds and seeds, and in terms of application has no buffer zone requirements and withstands rain in one hour .”
Another option for applying Shark to uncultivated land prior to planting is also a proven method of clearing both grass and broadleaf weeds, allowing for a clean start.
“Mixing Shark with glyphosate allows growers to control tough weeds that glyphosate cannot control when used alone,” advises Jeff. “There is a real improvement in the control of annual nettle, cranesbill and willowherb with the mixture and may allow lower rates of glyphosate to be used. A one month interval after application exists when of using this mixture before planting a crop, but this is not a problem in most situations.
The agronomist’s point of view
New fields leased by growers as clean potato land pose new challenges for weed management, points out Rob Ramsay, who provides agronomy on around 160 ha of fresh potato crops and transformation as part of 1,600 ha of walks in North Lincolnshire.
“We often face unknowns when it comes to managing new land, in terms of weed loads among other factors, so it’s important to start with clean land.
“Although it has no grass activity as such, it attacks weeds where the residual chemistry is a little weaker and gives us a good start to the crop, helping it to move away strongly. And if the weed load is low, it is possible to adjust the rate a little, perhaps reducing it to 0.3 or even 0.25 litres/ha if it is only small weeds. herbs, which is often the case.
“Rents for potato land are not cheap, so it is important to invest what is needed to get maximum returns. Add a residue like Artist (flufenacet + metribuzin) or Praxim (metobromuron), plus maybe Defy (prosulfocarb), for the addition of grasses and extra broadleaf weed control, and we have a good approach belt and suspenders for a good start to harvest.
Source: FMC Agro UK
Further information :
Jennie Green [email protected] or Liz Tomkinson at The Ad Plain, [email protected]