Accurate application of post-emergence grassweed herbicides in winter cereals will be especially important over the next few weeks after prolonged wet weather had hampered earlier attempts at control.

So, we asked Agrovista's technical manager, Mark Hemmant, how best to go about it for best effect: “Many spray programmes aimed at blackgrass and other problem grass weeds have been compromised, or not even started.

"Getting the best performance out of post-emergence actives is going to be critical. Choosing appropriate nozzles and setting them up correctly is vital to achieve the correct spray pattern and quality, particularly when grass weeds are small and difficult to hit.

“We need to ensure as much of the active ingredient as possible reaches the target,” added Mr Hemmant. “Grass weeds are extremely competitive and some, notably blackgrass, have become increasingly difficult to control.”

Nozzle angle is key. Agrovista trials consistently show that alternate angling of nozzles forward 30 degrees and straight down has produced significant improvement in control over the conventional vertical set-up, when using flat fan nozzles applying 100 litres/ha to create a medium spray quality (see graph).

Making the most of nozzle set-up to spray effectively

Making the most of nozzle set-up to spray effectively

“These are the parameters we would recommend,” he said. “We would also advise using blue 80-03s in the forward-facing position and blue 110-03s vertically to achieve the best droplet size and spray pattern.

“Angling nozzles in this way improves efficacy by breaking up the spray sheet to reduce drift overall, but increasing droplet movement at the target level which applies more active ingredient to the leaf. This is a particular advantage when you are faced with a small grass weed with upright leaves.”

Where drift is a concern, Lok-it can be added at 0.25% by volume, pointed out Mr Hemmant. “The product can also enable increased forward speeds of up to 14kph – in the right conditions, as long as booms are stable.”

Lilac 025 nozzles can be used to produce a finer spray quality if necessary and would be the nozzle of choice with twin lines, using forward-facing nozzles on the front line and vertically mounted ones on the back.

Matching the nozzle to the task:

The combination of nozzle choice and adjuvant is a cheap and simple solution that growers cannot afford to ignore, said Jonathan Cahalin, Agrovista’s head of arable in Scotland.

“There are no magic bullets when it comes to grassweed control, so anything we can do to improve control has to be worthwhile.

“It is not expensive to ensure the nozzle set-up is correct, especially when you consider the paybacks that can be achieved. Every extra percent of control is critical, particularly with blackgrass, and this is a really practical way of improving performance.

“On a more general note, given the wide variety of tasks a sprayer has to perform, operators should have more than one set of nozzles and should replace them regularly to maximise efficacy and boost returns.”

To help growers better match nozzle to task, Agrovista is rolling out a UK-wide nozzle delivery service after a successful pilot scheme in Scotland.

“Plant protection products are not cheap, so we want to ensure that growers can get the best return on their investment,” said Mr Cahalin.

“Our agronomists can now not only advise on which product is most appropriate to use and how to get the best from it, but also supply to growers the right nozzle technology to maximise efficacy and boost returns.”

Alternatively, growers can contact Paul Soppit, who looks after Agrovista’s new sprayer care facility at its Dundee depot, which dispatches to all corners of the UK – usually within 48 hours of an order.

It carries a large stock of nozzles from leading brands including Hypro, Syngenta, Teejet, Billericay and Lechler.