As worries about blackgrass increase, farmers are increasingly turning to Avadex granules. Andy Collings reports on a new piece of equipment that claims to make application of the product more accurate

The arable farmer’s armoury of products to control blackgrass is shrinking faster than an ice-cream in August. This hard-to-deal-with weed now infests more than 60% of the nation’s wheat crops – an area equivalent to 1.2m hecatres. And as other methods fall by the wayside, growers are increasingly falling back on Avadex Excel 15G granules to provide control.

According to Frontier’s technical manager Stuart Hill, blackgrass has flourished thanks to wheat-heavy rotations (which have made it difficult to get effective control) and extreme weather (which has hampered cultural control measures).

Chuck in the withdrawal of several key products and the ability of growers to keep on top of blackgrass has been seriously impaired.

See also: Avadex granule applicator gives good blackgrass control

“There are now just six main approved residual active ingredients,” Mr Hill points out. “And all but tri-allate (the active ingredient in Avadex) are affected in varying degrees by EMR – enhanced metabolism resistance. So it’s not hard to see why there has been a rapid upsurge in interest for Avadex.”

The volume of Avadex used has doubled every year since 2010, he says, and has been matched by an equally dramatic rise in the equipment to apply it.

New applicators can help

Gainsborough-based company Horstine, one of several manufacturers of this sort of equipment, says it has sold more than 40 applicators so far this year.

“With the virtual demise in Avadex use in past decades, our production of applicators designed to apply the product came to a halt about 10 years ago,” explains commercial manager Rob Starkey. “But fresh interest has led us to restart production with an updated design which draws on the latest developments in electronic application control.”

The company’s newly launched TMA4 pneumatic applicator applies small granules and comes in tractor-mounted or trailed versions. Both versions have a 12m boom with eight outlets at 1.5m spacing and plans are afoot to build a 24m version. There is no break-back on the 12m boom, though.

“There have been cases where growers needed a wider working width to suit their tramline spacing and we have fitted feed pipes and outlets on to a sprayer boom,” says Mr Starkey. “It’s a system that can be attached to the rear of a set of rolls, too.”

Individual metering

The distribution system on the TMA4 uses individual metering rotors for each of the outlets rather than an eight-point distribution head supplied from a single metering rotor.

Granules are delivered to the two metering blocks from a 380-litre hopper. The rotors are turned by a variable speed electric motor which, through a GPS system, is able to respond to changes in forward speed and maintain the required 15kg/ha application rate.

Granules pass into individual delivery pipes in which air generated by a hydraulically driven fan is flowing and conveyed to the outlets, the aim being to provide a double overlap. There’s a calibration system, too.

Horstine also offers a trailed version that can be hooked up to an ATV or farm buggy. This uses a 6.5hp engine to drive the fan and an alternator to generate electricity for the metering motors and control system.