A new total weedkiller which gives quicker burn-down on broad-leaved weeds and works more effectively at lower temperatures than glyphosate could make it a better bet for clean-up sprays of land going into root crops this spring, its manufacturer says.
Thunderbolt, containing glyphosate and pyraflufen-ethyl, also improves control of some broad-leaved weeds that straight glyphosate finds difficult, such as annual nettle, willow weed, cranesbill and volunteer oilseed rape, says Glyn Jones of Nichino Europe.
Those attributes should make it fit particularly well for cleaning up land going into root crops this spring, as well as for autumn stubbles, he suggests.
“Glyphosate works best when temperatures are above 15C, which isn’t going to happen very often pre-planting in the spring,” he notes.
But pyraflufen-ethyl is light rather temperature dependent, making it more flexible. It does need some warmth, he acknowledges, but when spray conditions are suitable in the spring it will do a job. “For example, it is a struggle to get on with glyphosate before sugar beet drilling starts in mid March, whereas you won’t with this.”
As well as meaning it can be sprayed in cooler conditions, pyraflufen also gives much quicker burn down of broad-leaved weeds without affecting glyphosate’s activity on grass weeds, says Camlad Agritech‘s John Davies, who is acting as Nichino’s UK agent for the product.
“It is not as fast as paraquat was, but in trials we’ve seen weed collapse and die-back after just 60 hours, with the difference compared with glyphosate most evident on weed species glyphosate isn’t so good on.”
The fast burn-down is particularly useful for growers looking for a quick turnaround before drilling, Mr Jones says. “From a cultivation perspective removing the green matter quickly might mean you can drill directly into it, rather than doing another cultivation pass.”
That’s where Agrovista’s Mark Hemmant sees Thunderbolt fitting in particular. “We see it being used in pre-plant situations where you have difficult broadleaved weeds. Previously the best legal option was a mix of Roundup and Shark, but that had a two to four-week planting restriction, whereas this is just two to five days depending on dose.”
In the autumn control of volunteer oilseed rape, in particular, could also be a driver for using the product, Mr Davies says.
Farmer trials in Cambridgeshire managed to take out “dinner-plate” size oilseed rape sprayed in October, Mr Jones notes. “Glyphosate barely does the job at that time of year. This will do those tough situations, but needs to be at the right rate.”
Typically for general broad-leaved weed control the rate should be 1.5 litres/ha. Perennial broadleaved weeds require a 4.0 litres/ha rate.
In trials the lower rate has given around 50% control of annual broad-leaved weeds in eight days compared with just 15% from 540g/ha of a 360g/litre glyphosate product. “Typically control is six days faster with no loss of overall control,” Mr Davies says.
But the product is more expensive, Mr Jones admits. “It is around 35-40% more than a standard Monsanto glyphosate.”
That makes it expensive if the target is just grass weeds. In that case glyphosate remains the best option, Mr Davies acknowledges. “Glyphosate doesn’t fail against grass weeds unless there is a good application reason, but Thunderbolt does give the same activity using 30% less glyphosate.”
Thunderbolt will be available through Agrovista and ProCam this season.