EAMUs secured

Authorisations secured following SCEPTREplus trials for herbs

• Devrinol as a herbicide for spinach and herbs
• Emerger as a herbicide for caraway, dill and parsley
• Venzar 500SC as a herbicide for outdoor leafy vegetables and fresh herbs

Weed control trials

These trial aimed to identify new crop-safe herbicides which could replace linuron.

The wide range of herb species makes identifying crop safe herbicides for each species difficult.

Linuron has been a key component of herbicide programmes for a number of herbs, along with Venzar Flow. The withdrawal of linuron left growers with limited options for pre-emergence weed control.

Weed control for transplanted herbs

• Crop Group: Leafy vegetables - herbs
• Target: General broadleaf weeds and grasses
• Period: May – December 2018

Conculsions

Pre-planting

• Aclonifen was safe to nearly all herb species when applied at up to 2.0l/ha, with the exception of oregano, which was not safe to use pre-planting at any rate.
• Devrinol 450 SC has been approved for use at 0.85l/ha and is safe to use on chamomile, mint, sage and thyme at that rate.
• AHDB9918 was only safe to tarrago at pre-planting

Post-planting

• Centurion Max was safe to all herbs in trialwhen applied up to 2.0l/ha
• Aclonifen was more damaging post-planting, and was safe only to chamomile, tarragon and thyme at 0.5l/ha
• AHDB9981 was safe for chamomile, mint, oregano and thyme
• Oblix 500 was safe to mint and oregano up to 1.0l/ha and 4l/a for sage and tarragon

There is at least one promising pre- and post-planting herbicide for each herb species which can be taken forward for testing in the field. They also will be considered for EAMU applications.

• Crops: Leafy vegetables (herbs)
• Target: Broadleaf weeds and grasses
• Period: May - Dec 2018

Conclusions

Pre-emergence

For those herbs where germination was greater than 70% (basil, coriander, dill and fenugreek), the following conclusions can be drawn:

• Aclonifen was safe to nearly all the herb species when applied at up to 2.0L/ha. Basil was an exception
• Devrinol 450 SC was safe to basil and fenugreek up to an application rate of 2.8 L/ha. However, it has subsequently been approved for use at a lower rate of 0.85/L/ha and wasn’t tested at that rate in the trial.
• AHDB 9918 was only safe to dill

Post-emergence

For those herbs where germination was greater than 70% (basil, coriander, dill and fenugreek), and where they were unaffected by the hot weather, the following conclusions can be drawn:

• AHDB 9981 was safe to dill and fenugreek
• Oblix 500 was safe to all herbs when applied up to 2.0 L/ha
• Centurion Max was safe to all herbs when applied up to a rate of 1.0 L/ha

There is at least one promising pre- and post-emergence herbicide for each herb species which can be taken forward for testing in the field, as well as warranting investigation for an EAMU

• Crops: Leafy vegetables (herbs)
• Targets: Broadleaf weeds and grasses
• Period: Aug- Sep 2017

Conclusions

For those herbs where germination was greater than 60% (chives, coriander, dill, fenugreek and parsley):

Pre-emergence

• Devrinol 450 SC was safe to nearly all the herb species when applied at up to 1.4 L/ha, with the exception of dill
• AHDB 9987 was only safe to coriander up to half dose
• AHDB 9974 was safe to use on coriander up to single dose or label rate, and half dose rate in parsley

Post-emergence

• AHDB 9974 was safe to use over coriander up to double-rate, but only up to half rate / dose for parsley
• AHDB 9981 was safe to dill and fenugreek up to single dose
• Centurion Max was safe to all herbs when applied up to a rate of 1.0 L/ha
• AHDB 9953 was safe to all herbs when applied up to half dose

There is at least one promising post-emergence herbicide for each herb species which can be taken forward for testing in the field and warrant investigation for an EAMU. For pre-emergence there is a promising herbicide for each species except dill, which was sensitive to all tested.

• Crops: Leafy vegetables (herbs)
• Target: Broadleaf weeds and grasses
• Period: March - Dec 2019

Conclusions

• Emerger 0.5 L/ha was safe to use over parsley, coriander and chives, causing only a slight stunt to parsley at this rate.
• Emerger was also safe to use in parsley and coriander at a post-emergence timing when applied in a tank-mix with Stomp Aqua 2.2 L/ha
• The higher rate of Emerger - 0.75 L/ha was safe for use over coriander and chives only.
• AHDB9981 caused stunting at all rates used in the trials, but may be safer at a lower rate and offers a useful range of weed control
• AHDB 9860 2.0 L/ha caused yellowing of chives, but was safer at 1.0 L/ha. This product was not tested post-emergence over parsley and coriander
• AHDB 9855 was only safe to use on chives

Emerger 0.5 L/ha applied either alone or in a tank-mix with Stomp Aqua was the safest to the widest range of herbs in these trials an authorisation for the product for use in coriander, parsley and chives would improve weed control for herb growers. AHDB9981 would also fill gaps in control of cleavers, groundsel and black nightshade.

• Crops: Leafy vegetables (herbs)
• Target: Broadleaf weeds and grasses
• Period: Mar - Dec 2019

Conclusions

• Emerger 0.75 L/ha reduced weed numbers and was safe to use in parsley, coriander and chives, causing only a slight stunt to parsley at this rate.
• The higher rate of Emerger - 1.75 L/ha was safe for coriander and chives only.
• Devrinol 0.85 L/ha was safe to coriander and chives only.
• AHDB 9860 2.0 L/ha reduced weed numbers, but was only safe to coriander at this rate.
• AHDB 9855 reduced weed numbers but is only safe to use in chives.

Emerger has an EAMU (4485/19) for coriander and parsley, and use as a pre-emergence herbicide should increase weed control in these crops. An authorisation for use in chives would be useful. It has not been tested in tank-mixes, therefore care should be taken if using this approach. Devrinol 450 SC has an EAMU (2121/19) for use in a range of herbs but was only safe to use on coriander and chives. It caused moderate stunting of parsley.