Accurate application of post-emergence grassweed herbicides in winter cereals will be especially important over the next few weeks after prolonged wet weather hampered earlier attempts at control.
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.
Agrovista technical manager Mark Hemmant said: “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.”
“We need to ensure as much of the active ingredient as possible reaches the target,” says Mark. “Grass weeds are extremely competitive and some, notably blackgrass, have become increasingly difficult to control.”
Nozzle angle is also key. Agrovista trials have consistently shown 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).
“These are the parameters we would recommend,” said Mark. “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, explained Mark. “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 are recommended 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 nozzle to 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 very successful pilot in Scotland.
“Plant protection products are not cheap, so we want to ensure that growers can get the best return on their investment,” added Jonathan.
“Our agronomists can not only advise on which product is most appropriate to use, and how to get the best from it, but can now 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 the Dundee depot, which dispatches to all corners of the UK usually within 48 hours of an order.
Agrovista carries a large stock of nozzles from leading brands including Hypro, Syngenta, Teejet, Billericay and Lechler. Further details at www.agrovista.co.uk