Herbicides for Planting year in Blackcurrants

Herbicide failure on planting year has a significant cost--$2-3k/ha in hand weeding costs, or a year’s delay in harvestable yield ($10-12k/ha).

The focus of this year’s trial work was to identify combinations of herbicides that are safe on cuttings, broaden the herbicide group rotations away from triazines (gp 5) and away from oxadiazon (concern about loss from regulation) and still give adequate weed control.

This trial built on the lessons from the last two years (crop safety and efficacy), as well as experience from Europe and advice from Matthew Crampton.

Summary of key outcomes

Eight products/combinations were evaluated for weed control efficacy and plant safety for pre-emergent weed control in blackcurrant cuttings on the establishment year.

Three treatments stood out as viable alternatives to the Exadia/Simazine grower standard.  All were combinations of products:

• Terb/Oxy (groups 5/14) was remarkably effective, and the cheapest option.
• Artist/Stomp (groups 15/5/3) was also very good on the main weeds, including wireweed.  Adding Stomp gives significant improvement over Artist alone. 
• Chateau/Stomp (groups 14/3) was very good on broadleaf weeds, but would need an addition of a strong grass pre-emergent or a follow-up addition of a grass-selective herbicide by November.

Sakura, Alion and Callisto were surprisingly ineffective in a pre-emergent application for blackcurrant establishment.

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