New herbicide to help replace linuron

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Bayer’s new herbicide Emerger (aclonifen) has been authorised for potatoes and gained EAMUs for carrots, parsnips, onions and a range of herbs.

The company’s campaign manager for root crops Edward Hagues says: “Emerger is a consistent performer against a wide range of weeds and will become a key herbicide for the potato crop. In trials it has shown high levels of activity against nettles, polygonums, brassica weeds (charlock, runch, volunteer OSR and shepherd’s purse), Chenopodium weeds (fat hen and orache) and made a good contribution on grass weeds.”

Containing 600 g/L aclonifen in a suspension concentrate (SC) Emerger is authorised for one pre-emergence application in potatoes at a maximum individual dose of 1.75 L/ha. Mr Hagues says it is a flexible product that can be used effectively in combination with other potato herbicides. “From European experiences the mix of 2 kg/ha Artist (flufenacet + metribuzin) with 1.75 L/ha Emerger will be a robust programme for pre-emergence weed control.

“Uptake is by shoots not roots. As the weed emerges the hypocotyl (broad-leaved weeds) or coleoptile (grasses) picks up the herbicide as it grows through the soil surface. This means it needs to be applied uniformly to an even, friable seedbed to form a consistent film.”

Weed symptoms are bleaching and necrosis of young shoot tissue as it develops. The active substance is absorbed strongly onto soil particles and has very low water solubility making it very low risk to groundwater. Residual activity is usually two to three months.

Bayer campaign manager for horticulture Tim Lacey adds: “Emerger will be a big help to vegetable growers. The loss of linuronwas looking set to make weed control almost impossible in many crops. We have done our utmost to get Emerger authorised for use this year and are indebted to AHDB, BCGA and BLSA for their support.”

There are three EAMUs covering Emerger’s use in carrots, parsnips, root parsley, garlic, onion, shallot, caraway, dill and parsley which permit one pre-emergence treatment at a maximum individual dose of 1.75 L/ha. They were sought by the AHDB EAMU programme following good results in SCEPTREplus trials.

Prior to the loss of linuron, the standard pre-emergence mix for carrots was pendimethalin + clomazone + linuron. Mr Lacey says: “In trials we’ve seen similar weed control where Emerger was swapped for linuron so we expect pendimethalin + clomazone + Emerger to become the new standard.”

In addition to the broad spectrum of control listed by his colleague in potatoes, Mr Lacey says carrot, parsnip and onion growers will benefit from its contribution to control of annual meadowgrass, knotgrass, charlock and cleavers and its activity on groundsel.

Onion growers are advised to read the advisory information on the EAMU and to note that use of Emerger on onions grown from seeds requires extreme caution as damage may occur if cool and wet conditions occur after application.


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