Bixlozone in Isoflex active is from the isoxazolidinone chemical family and will be FMCs first new herbicidal mode of action in cereals for several decades.

Isoflex provides both systemic and contact activity, with residual control and can be applied pre-emergence and early post-em to control key grass-weed and broad-leaved species, including ACCase and ALS resistant black-grass and ryegrass, according to FMC.

It is also said to provide effective control of other key weed species including chickweed, speedwell, groundsel, mayweed, shepherds purse, dead-nettle and cleavers.

Dependent on approval, the herbicide can be used in winter cereals and as a pre-em in oilseed rape, maize and other spring crops including potatoes.

Gareth Jones, UK technical leader at FMC says its application timing will offer growers flexibility in the field and lasting control of key grass and broad-leaved weed species.

If we get the expected label in cereals it should be able to be applied from pre-em to peri-emergence of the weed, which is probably one or two leaves of the crop , so it can either be in a pre-em residual stack or follow up spray.

Post-emergence of the crop but peri-emergence of the weed is the key timing, and it will act as an ideal complementary mixing partner for broad-leaf weed herbicides, says Mr Jones.

With other new actives coming to the market, Mr Jones sees an opportunity to reset the autumn residual stack over the next two to three years and reduce risk of further resistance development.

We are already seeing flufenacet insensitivity in ryegrass and I think we will see that with black-grass in the next few years.

Isoflex helps to contribute to the new strategies we need.

I think we will remain in a stack situation, where it will be a contributor.

It is not going to be a standalone product for black grass control but the key is it is a different mode of action.

Current programmes may be based on flufenacet, pendimethalin, DFF and prosulfocarb but future programmes could be based on Isoflex, cinmethylin, picolinafen and aclonifen.

There will still be a place for the older products at whatever rate they will be approved.

After acquiring half of DuPont and much of its R&D in 2017, FMC has a strong pipeline of chemical and biological products including three new herbicide modes of action.

Isoflex active will be available partnered with another of FMCs emerging new herbicide products which has an alternative mode of action.

Subject to registration, it is hoped it will be available for autumn 2024 in the UK and 2025/26 in Europe.

The herbicide is already in use in cereals and oilseed rape in Australia and is going through the registration process in Argentina.

Isoflex was discovered during the original development of the herbicide clomazone, and although it has a similar mode of action, they are very different molecules, with Isoflex offering differentiated crop safety in comparison, says Mr Jones.

It works by inhibiting carotenoid production in susceptible plants carotenoids are pigments that are critical to protecting photosynthetic processes and ensure normal plant growth and development.

This effect, which is often referred to as bleaching, stops the photosynthesis in target weeds, leading to their death.

• Subject to UK registration Isoflex active will be available for autumn 2024
• The new mode of action provides both systemic and contact activity with residual control
• Effective on key grassweed and broad-leaved species including ACCase and ALS resistant blackgrass and ryegrass
• Can be applied at pre-em or early post-em
• In trials shows comparable efficacy to competitor products for black-grass and better ryegrass control