Sugar beet growers ordering seed for next season are being urged not to disregard new seed treatments because of restrictions on using some pre-em herbicides.

Both long-time market leader Gaucho (imidacloprid) and new Syngenta offering CruiserForce (thiamethoxam + tefluthrin) should not be used in conjunction with lenacil pre-emergence because of negative impacts on emergence, says Broom’s Barn herbicide specialist Mike May, although there is no restriction with Bayer CropScience’s Poncho Beta (beta-cyfluthrin + clothianidin).

But the restrictions need not affect the vast majority of growers’ choice of seed treatment, he says. “Lenacil is better used post-emergence than pre-emergence.”

Growers opting to apply a pre-emergence treatment would be better choosing chloridazon, he suggests. “It has a similar weed spectrum to lenacil, but can be used at a lower, cheaper rate.”

The shift towards fewer farms with larger areas of beet and the need to cut costs will drive growers towards simple spray programmes, says Mr May.

“Chloridazon pre-emergence followed up by two post-emergence sprays, or just three post-emergence treatments without a pre-emergence, are likely to be the most cost-effective options regardless of seed treatment.”