Sugar beet and maize will be vying for their share of sprayer time over the next couple of weeks to keep competitive weeds at bay, says Agrovista agronomist Craig Green.

Article taken from Farmers Guide

Most sugar beet crops under Craig’s care will have received a pre-emergence herbicide, given this season’s adequate soil moisture levels.
“Growers’ decisions are driven by soil moisture – many prefer to leave the pre-em and go early post emergence when seedbeds are dry, but this year we’ve had plenty of rain to activate chemistry,” says Craig.
Subsequent advice will be tweaked according to whether fields received a pre-em spray or not.
Craig’s pre-em recommendations will have bought some flexibility in the post-em programme. He recommended chloridazon + metamitron, as Volcan Combi at 3 litres/ha, or straight chloridazon as Pyramin at 2.5kg/ha where fat-hen was absent.  The chloridazon will have given good initial control of black bindweed, which is rife in many beet areas, while metamitron will have boosted activity on early-emerging fat-hen.

“Chloridazon can only be applied pre-emergence so if you miss this timing you are left with phenmedipham post-emergence, which is less effective on black bindweed,” says Craig. “Once the weed gets to one true leaf, it is difficult to take out.”
Growers who applied a pre-em can allow crops to grow a bit longer and weather before returning with the sprayer with the first post-em spray, reducing the risk of checking crop growth.  Craig recommends Betanal Maxx Pro at 1litre/ha when beet cotyledons are fully expanded. “The product contains ethofumesate, which tops up residual activity, and phen- and desmedipham that provide strong contact activity against a range of grass weeds. It also contains Lenacil, which hots the mixture up on weeds.”
He will add 1 litre/ha of Target (metamitron) where fat-hen is a problem. Another favoured ingredient in the mix is KryptoN, a 28% liquid nitrogen formulation that acts as a crop safener.

“I really rate it – sugar beet can break down desmedipham and phenmedipham but it needs nitrogen to do it, so this will minimise growth check.”
Crops that did not receive a pre-em will need treating earlier, before beet cotyledons have fully expanded. “I’ll use Betanal Maxx Pro, but at no more than 0.75 litres/ha, with Target at 1 litre/ha. I’ll add KryptoN at 0.75 litres/ha.”
The mix is less flexible than the one following a pre-em, and doesn’t allow much leeway if weather conditions hamper spraying. “You also need to be careful of spraying if we get warm days and cool nights – large temperature differences can stress small beet plants.”
Subsequent contact sprays will depend on the weather. If it is set fair, he’ll use the FAR little and often approach; if the forecast is doubtful or where sprayer time is limited he’ll go for the Broadacre approach.
“FAR does result in a cleaner crop with less risk, but for growers with big acreages or who rely on a contractor applying just two further applications in two big hits does have its advantages.”
He’ll use Betanal Maxx Pro plus Target as appropriate, or switch to Beta Team (desmedipham, ethofumesate + phenmedipham) to shave costs.  Debut (trisulfuron-methyl) will be added to control fumitory, volunteer OSR and cleavers, while grass-weed control will require a pass with Falcon (propaquizafop). Dow Shield (clopyralid) will take out creeping thistle.