The revival of Avadex has spurred manufacturers to produce a mass of new equipment that can distribute microgranules from sprayers, seed drills, rolls and purpose-built applicators.

“Avadex Excel 15G has a key role to play in a control-and-resistance strategy because it has a mode of action different from almost all other autumn-applied herbicides and there has been no field experience of resistance in over 40 years of use in Europe,” says Dominic Lamb of Avadex manufacturer Gowan.

See also: Chafer shows ultra-accurate applicator 

“Avadex is not a silver-bullet solution to blackgrass control; growers need to use all the different technologies and measures, including crop rotation and other cultural methods,” he adds.

“But it does play a critical role by boosting overall performance of the chemical ‘stack’ by increasing control of a range of grass weeds, including wild oats, and it can be used in winter barley where there are very few active ingredient options.”

However, the rush back to Avadex has raised concerns over application as growers pull out old granule and fertiliser spreaders from the back of sheds and rig up spreading systems on to drills, rollers and other implements.

So what’s the best way to apply Avadex, and when?

It can be applied before drilling of spring barley and legumes, incorporated in the final pass, distributed after drilling but before the crop has emerged and post-emergence in winter wheat and barley.

But in all cases, it must be before the blackgrass has emerged.

Broadcasting from a multi-point system on the back of a seed drill is an obvious place for application because it saves a separate operation and ensures the granules are in place ready for blackgrass to germinate.

But when drilling wheat it’s important to get good separation between the seed and granules.

“That separation can be less good where the granules land in moving or settling soil, with rolling then further decreasing separation,” warns Dominic Lamb from Avadex manufacturer Gowan.

“Bear in mind also that drilling speeds have increased to 14-15kph with modern disc and tine drills, and the Avadex label states a maximum of 8kph to maintain the integrity of the spread pattern.”

At fast drilling speeds, he adds, it is possible for a vortex effect to influence the spread pattern from the outer distribution plates and leave strips of untreated ground. However. many growers apply Avadex from the back of the drill with good results.

What about from rolls?

This saves a separate pass and gives the drill driver one less thing to think about. There is a risk, though, that wet conditions after drilling will delay rolling until after blackgrass emergence.

It’s important to recognise that full and even coverage is essential. Installing and maintaining the “splash” plate deflectors at the correct height, angle and orientation is therefore crucial.

“Bear in mind also that Avadex application requires a PA 4G qualification, so that would apply to the roller operator in this case,” adds Dr Lamb.

10 machines to apply Avadex granules

1. Horstine Twin Air
   

Horstine’s 300-litre stainless steel hopper uses a metering system originally designed for microgranule application. The hopper has a removable divider making it also suitable for broadcasting oilseed rape and slug pellets without mixing the two.

High capacity fan and hydraulic metering unit drives make it suitable for Avadex application through up to 16 outlets.

2. Horstine TMAir
   

Electrically driven fan generates the granule (and small seed) transporting airflow, with precision metering achieved by individual rotors for each outlet.

3. Stocks Ag applicator
   

A higher-powered fan option is recommended by Stocks AG for Avadex application from drills, cultivators and rolls using the TurboJet air seeder.

It provides 25% more air volume to cover wider working widths using up to 20 splashplate broadcasting outlets, each with its own metering roller within the cassette-type metering system.

The ‘V’ shaped spreading plates are carried on a steel channel rail – they slide and lock into position – and the angle is also adjustable to suit the implement width.

4. Techneat applicator

Techneat’s Avadex granule application system for drills or rolls is 550mm wide and attached using a three-point mounting frame.

A 200-litre plastic hopper and single-point metering mechanism, air fan and distribution ‘mushroom’ feed the close-spaced distribution plates, with an electronic GPS system providing the metering control.

Cost £6,000-£6,500

The fan can have electric drive or – preferably, says Techneat – a hydraulic motor. Cost for a 12m mounted unit is £10,000, while a trailed 12m one is £11,600.

A 24m mounted unit with 1,200 litre hopper and hydraulic-folded boom is £29,000.

5. Kuhn Aero/Amazone Jet
   

Tractor-mounted pneumatic broadcasters such as the Kuhn Aero and Amazone Jet, which are no longer available new, are being pressed into service as Avadex applicators, providing good work rates at boom widths up to 24m.Gowan provides set-up and calibration guidance on its website www.avadex.co.uk.

6. Horstine TMA4
   

Horstine re-introduced its 12m TMA4 purpose-built microgranule boom applicator last year.

It can be drill or roll mounted but is more commonly used on a tractor or operated in trailed form behind an ATV with a small petrol engine driving the fan.

Individual rotors feed each distribution outlet, which applies the granules over 1.5m, with two metering units supplying four outlets each.

1. Opico/Techneat
   

Two new alternatives are the Opico Micro Pro 16 and the Techneat AvaCast Gr, both of which come in mounted or trailed form.

The 12m GeoBoom developed for the AvaCast designed to keep level and steady over a field surface.

The Opico Micro Pro 16 can spread across 12.5m using its 16 outlets at the maximum 75cm spacing to get a robust double-overlap spread pattern.

Each outlet is fed by a Hatzenbichler individual metering roller mechanism with boom outlets adjustable to balance the air-flow and electronic control with radar speed measurement is available. to keep the application rate consistent.

9. Techneat Geoboom
   

Instead of being rigidly mounted, Techneat’s GeoBoom is carried on a two-point suspension to help keeo it steady when passing over depressions and bumps.

It can be retro-fitted to existing Techneat trailed applicators, which have an engine to power the granule distribution fan.

10. Horstine Cascade
    

Horstine’s  Cascade is another new option. It goes up to 24m, with up to six sections with individual shut-off and sizes to suit different tramline spacings – 15m (30m tramlines), 16m (32m), 18m (36m), 20m (40m) and 24m (24m and 48m tramlines).

Rob Starkey of Horstine Farmery says the implement has been developed to do more than just apply herbicide microgranules to help growers justify it.

“It will put on slug pellets at a fixed width, could be used to broadcast cover and companion crops and is equipped for application rates up to 500kg/ha at 12kph, so it could have a role top dressing or applying P&K fertilisers,” he points out.

“The 1m spaced spreading plates give a double overlap application with plus or minus 2% accuracy – which is well within the 10% NSTS margin.”

The linkage-mounted implement has a 1,500-litre plastic hopper with individual outlet metering and hydraulic drive to the fan.

An RDS Athene touch screen controller provides manual or auto section control and is equipped for variable rate application for fertilisers and guidance for running between tramlines.