Trials look at cost-effective spring weed control

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A Nottinghamshire farm is hosting field scale trials looking at cost-effective options for spring weed control.

The trial being run at Poole Farms, Southwell in Nottinghamshire is comparing the performance and overall cost-effectiveness of two mesosulfuron +iodosulfuron- based herbicides Pacifica and Cintac, as well as aiming to gain some insight into the most cost -effective adjuvant partners.

Cintac and sister product Niantic were the first off-patent mesosulfuron +iodosulfuron herbicides to be available to the UK arable market. Manufactured by Dublin- based off-patent manufacturer Life Scientific, Cintac is produced by the unique process of reverse engineering.

“This is the ability to clone a product from the original resulting in a product accepted as comparable by the regulatory authority (Chemical Regulation Division) –which means it is the same as the reference product –  and in the case of Cintac this is Pacifica,” explains Ruth Stanley, technical manager for Life Scientific.

She recognises the difficulty that whilst the product is recognised as comparable by CRD, many agronomists and growers want to see how it performs in the field.

“This is what we hope to demonstrate in this trial.”

Working together with farm contractor Alastair Baseley of JS Peak & Sons and agronomist Martin Hoggard of ProCam, the trials are spread across two separate fields .

The trial area is just short of 10ha and is being run on a split field trial basis on a field of Graham winter wheat, explains Martin Hoggard.

He points out that there are heavy black-grass populations across both fields, along with a smattering of brome and various broad leaved weeds.

“However we have gone on with a pretty hefty pre-emergence programme so if we get onto the black-grass early enough it will be interesting to see what control we get. We have not used any sulfonyl-urea based herbicides on these fields for a couple of years.”

“The crop had also had an application of 0.5l/ha of Pontos (flufenacet + picolinafen) post-emergence at growth stage 11.”

Mrs Stanley adds that the herbicides will mop any of the broad leaved weeds such as chickweed, and volunteer OSR as well as brome and wild oats that are also present.

The first trial will compare the performance of Pacifica and Cintac directly. Both products will be tank mixed with the adjuvant Cogent.

“We are not expecting to see any differences in control between the Pacifica and Cintac – that’s the whole point of the trial – as the products are the same!”

“What we will demonstrate is that the level of control from the Cintac is the same as that offered by the Pacifica.”

“We will leave an unsprayed strip to allow us a comparison with treated and untreated.”

Mrs Stanley will be carrying out plant counts of existing weeds before and after spraying to ascertain exact numbers.

The second trial will look at how Pacifica and Cintac compare when mixed with different adjuvants; the Pacifica will be mixed with BioPower and the Cintac with Cogent.

We will compare the differences in these treatments, she adds.

By demonstrating that Cintac offers the same levels of control as Pacifica, and at a more cost effective price it opens up the market-place to more choice for growers and agronomists, she points out.

“Its also worth noting that authorisation for Pacifica use expires on 30 April 2020, with all sales and distribution needing to happen before 30 April 2019, however this is not the case with Cintac which does not carry any expiry on authorisation of use. 

Getting the most out of spring spraying with independent expert Tom Robinson

Last year independent spray expert Tom Robinson conducted a trial at Thurlow Estates looking at the importance of spray application technique to maximise spring weed control. 

The trial evaluated spray coverage of Cintac + an adjuvant on water sensitive paper targets @GS30.

Four nozzles were compared, each at 3 different boom heights using a commercial sprayer.

Results showed that nozzle height is important for all nozzles however the coverage on vertical surfaces doubled at 40 and 50cm vs 100cm.

For the best performance the nozzle height should be no more than 50cm, noted Mr Robinson.

Nozzle height also has an effect on spray coverage, he adds.

The traditional 110° Fanjet did an acceptable job although it is sensitive to boom height and has a poor drift profile.

3D Angled spray produced the best coverage of vertical surfaces.

80° Flat fan produced the best coverage of flat surfaces.

Guardian Air was the least sensitive to nozzle height.

As blackgrass emergence in the replicated plots was too variable across the trials areas to allow differentiation of treatments by efficacy, the trial is being repeated this year.

Poole Farms Trial

  • Soils are heavy clay
  • Cultivations: Min till with a Sumo, Cambridge rolled and power harrowed before drilling.  Fields have not been ploughed for the last six years.
  • The wheat follows oilseed rape and was drilled on 23rdOctober 2018 at a rate of 190kg/ha.
  • Pre-emergence herbicide applications included: 0.5l/ha flufenacet, 4.2l/ha Bulldog (pendimethalin +diflufenican), full rate Avadex.
  • Sprayer is 24m Bateman using a 110°Flat Fan nozzle


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