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Crop Advice & Expertise

The Benefits of Post-emergent Herbicide Pacifica Plus

Pacifica Plus was available for the first time in spring 2020 as a straightforward single product to control a range of grass weeds and broad leaved weeds. As a step forward from conventional Pacifica, it improves broad-leaved weed control.

H2: Weed pressure in crops for the current season

Wheat area has rebounded to normal levels after the 2019 wash out, but wet weather has still caused problems in the current season. Wind and rain disrupted drilling and herbicide applications, opening the door to greater weed pressure in crops.

“The settled spell at the start of November meant that most of the planned wheat went in this year,” says Darren Adkins, Bayer Commercial Technical Manager in Lincolnshire. “There was an understandable tendency to prioritise drilling, so Liberator (flufenacet + diflufenican) and other residual herbicides didn’t all go on at the optimum pre-em timing.”

Seedbed quality was also affected by the wet weather, which gives weeds an advantage. Walking crops field-by-field to assess the situation is essential, according to Mr Adkins. There is lots of variation in how well wheat established and weed levels.

Some farmers drilled early and there was protracted black-grass germination, all of which adds to the number of crops in need of a follow up herbicide this spring.


H2: Utilising Pacifica Plus for weed control

Oxfordshire based agronomist Sam Clarke has noticed a similar pattern in his region, with an estimated 80% more wheat drilled than last year. As the weather deteriorated, farmers had to use tine drills and couldn’t roll and some crops didn’t get the autumn herbicide programme at the right timing (or at all).

Mr Clarke used Pacifica Plus (mesosulfuron + iodosulfuron + amidosulfuron) on a limited area of wheat last year and expects it to feature again this spring.

With a similar situation this year, albeit on a much larger wheat acreage, post-emergence sprays will be important to tackle a wide range of weeds. The Pacifica Plus worked very quickly on cleavers and did well against a range of grass-weeds. It’s very effective against brome and is the best available on black-grass, according to Mr Clarke.

“Pacifica Plus is the best performing product against a wide range of grass-weeds, including black-grass and is particularly useful when the focus moves to spring grass-weed management, as it is likely to for spring 2021.”

  • Lindy Blanchard, Bayer’s Herbicide Campaign Manager


H2: The importance of long-term weed management

Long-term weed management shouldn’t be overlooked. Reducing seed return by any means possible is essential, especially with such a limited range of profitable crops. Spring cropping and diverse break crops will do a great job controlling black-grass, but farm finances often rely on a large area of winter wheat.

Farmers need to maximise the opportunity to control weeds this season to prevent problems in the following crop, especially in tight rotations with lots of winter cropping. Each head of black-grass produces up to 200 seeds; that’s 200 more potential weeds to control in autumn.

With small differences in control leading to large differences in seed return levels, application timing and quality is essential. “Suitable conditions are vital to get the best results from Pacifica Plus,” says Mr Adkins.

“Active growth is absolutely essential for the black-grass to absorb the active substances to take effect. For blackgrass control, applying to small plants generally gives you the best chance of overcoming any kind of metabolic resistance. Apply to a dry or drying leaf with a fine–medium quality spray at 100–200 L/ha. As it is contact acting, avoid windy conditions because the spray has to land, settle and dry on the leaf to be effective.”


H2: Alternative post-emergent herbicide options:

(Mesosulfuron + iodosulfuron)

Controls a wide range of grassweeds in winter wheat crops including black-grass, wild oats rye-grass, plus the useful addition of chickweed and mayweed. 

Mesosulfuron + propoxycarbazone)

Good for targeting grass-weed only populations, excellent brome control.

(Mesosulfuron + iodosulfuron + diflufenican)

Annual meadow-grass control in crops that missed out on a pre-em.



This blog post is based on an article from the spring 2021 issue of Crop Focus magazine. The magazine is packed full of insight, advice and research from the world of arable farming to help you grow the most profitable crops possible. Over 90% of readers find Crop Focus an interesting read – it’s free to subscribe so sign-up today!