SCEPTREplus: Rhubarb

Late winter herbicide screen for rhubarb

• Crop: Rhubarb
• Target: Broadleaf weeds and grasses
• Period: March 18- May 19

Take home message

AHDB9996 and Sencorex Flow could improve control of Himalayan balsam and other broad-leaved weeds when included with current herbicide programmes, subject to authorisation.

Trial summary

The trial aim was to identify crop safe and effective herbicides for rhubarb weed control.

Himalayan balsam, docks and thistles are a particular problem for rhubarb growers. As well as competing with the crop for nutrients and water, they also hinder pickers making harvest inefficient.

As a perennial crop, there is only a short window where the crop is fully dormant where non-selective herbicides can be used safely.

Conclusions

• All treatments were crop safe
• AHDB 9996 performed best, based on the final weed cover.
• Sencorex Flow gave a similar level of control

• Target: General broad-leaved weeds and grasses
• Period: Apr 2017 - Mar 2018

The aim of this trial was to expand post-harvest herbicide options.

Conclusions

Approvals for AHDB 9981, AHDB 9982 or Shark for post-harvest use would enable growers to improve weed control in rhubarb crops. An approval for AHDB 9985 would improve the options available for grass weed control.

Period: Jul 2017 - Mar 2018

This trial aimed to give growers guidance in the use of Callisto, testing rates and timings of application post-harvest, as well as in tank-mixes with other herbicides approved for use on outdoor rhubarb.

Conclusion

For less crop damage it is advantageous to apply Callisto, or any mixes containing Callisto, as soon as possible after topping the crop, or before new regrowth is present if possible.