• Rake and Roll - An Integrated Approach to Blackgrass Management
• Grassweed Emergence Monitor
• This Edition's FAQs:
  • What nozzles should be used for an autumn application of UNITE or Broadway Star?
  • Can I apply a BYDV insecticide in tank mix with UNITE?
  • What cultivations are required before establishing OSR following an application of UNITE?
  • How can I control volunteer beans in Winter Wheat?
  • What is the current use up period on Doxstar, Grazon 90 and Pastor, and what is the position for these products next year?

The benefits of achieving a stale seed bed prior to the establishment of cereals and oilseed rape are well known, but not always easy to achieve when a fast turnaround between harvest and drilling, as with OSR establishment, is required.

To highlight the importance of an integrated approach to grassweed management, Dow AgroSciences are supporting the trial of a new cultural technique, the ‘Rake n Roll’ cultivator. The trailed implement manufactured by Tillso consists of spring tines which scratch the stubble surface, distributing straw trash and allowing any shed grassweed seed to come into contact with the soil. Tines go no deeper than 5 mm so soil to seed contact is achieved without burying the seed. This is crucial as blackgrass seed needs UV light to germinate, and if seed is buried it is more likely to lie dormant. A studded rubber roller follows the tines, pushing the seed into the soil and promoting conditions favourable for germination.

The emerged flush of weeds can then be sprayed off prior to drilling with a non-selective herbicide. This approach is ideal in situations where resistance is known or suspected and will optimise the performance of post-emergence herbicides.

Kerb Flo 500 and OSR establishment

When cultivating prior to OSR establishment, keeping blackgrass seed close to the soil surface will allow propyzamide, (which is most active within the top 5cm of the soil profile) to be more beneficial. Kerb* Flo 500 is a residual, soil acting herbicide which is taken up via the roots so any grassweeds germinating within this zone are optimised for control.

It is for these reasons that non-inversion cultivation and min-till techniques are more suitable for the activity of Kerb Flo 500.  Additionally, as there is no known resistance to propyzamide, blackgrass control across the rotation is optimised. 

Incidentally, if pyroxsulam products – UNITE* and Broadway* Star – were used in the preceding cereal crops for grassweed control there is no need to plough prior to the establishment of OSR - a useful plus.

When using Kerb Flo 500 in blackgrass situations, use at the full rate of 1.7 L/ha. The new high strength propyzamide herbicide optimises sprayer efficiency and reduces packaging waste. Soil temperatures of 8-10°C and falling will increase the effectiveness of Kerb Flo 500 in the soil and prolong its activity. Optimum soil moisture is also crucial in encouraging uptake via the roots. Kerb weather data, available as an e-newsletter, will give guidance on the optimum conditions for the application of Kerb Flo 500. Make sure you sign up to receive Kerb Weather Data reports direct to your inbox, see details below.

This season’s inclement weather has meant harvest has been delayed for many farmers across the UK and could mean that achieving a stale seed bed with non-selective herbicides is more of a challenge pre-drilling. Monitoring grassweed emergence will therefore be crucial for timely applications of graminicides this autumn. The Grassweed Emergence Monitor (GEM) is now in its third year, and provides growers and advisors with crucial information on the germination profile of key grassweeds.

Historical Patterns

GEM first began in the autumn of 2010, and already some key factors influencing emergence patterns have been recognised.

In 2010, key grassweeds had all emerged by late October and those who delayed treatments saw no new emergents but inevitably found themselves tackling bigger weeds. In 2011, when autumn was particularly dry, bromes and ryegrasses emerged quickly post-drilling whilst blackgrass germination was delayed until wet weather kick-started germination in early November, by which time pre-emergence herbicides had lost some of their vigour. Consequently for many, 2011/2012 saw a significant increase in blackgrass populations.

GEM Final Report Boxworth, Cambridgeshire. Drilled 20th September 2011.

Key: Note the graph shows cumulative grassweed populations.
A – Early germination of ryegrass and brome populations
B – Blackgrass emergence in response to rainfall
C – Winter kill sees decline in population.

Across both seasons the majority of grassweed germination has occurred in the autumn, with little emergence in the spring. Therefore delaying post-emergence graminicides until spring to catch the tail-enders may lead to a reduction in control, as plants will be much bigger in size. Sterile bromes and ryegrass are also predominantly emerging in autumn. Trials and demos have nearly always proven the time to control grassweeds is in the autumn when weeds are small.

Predictions for this season

This year we are hoping to monitor five representative UK sites in Cambridgeshire, Herefordshire, Oxfordshire, Wiltshire and Yorkshire. As in previous years this will involve monitoring;

• Three major grassweeds; blackgrass, sterile brome and Italian ryegrass and an unsown natural blackgrass population
• Two different timings, an ‘early’ late September/early October drilling and a ‘late’ timing at the end of October.

When conditions during seed maturation are cool and wet, blackgrass is more likely to lie dormant which may mean the germination period is extended this coming season. In such circumstances, a robust programme is integral. After application of a pre-emergence herbicide such as flufenacet, an application of UNITE at 270 g/Ha when weeds are small and actively growing is the best approach to blackgrass control. An additional residual such as Stomp Aqua applied in conjunction with UNITE may be beneficial.

In order to maximise performance of UNITE:

• Use as part of a programme and follow WRAG guidelines
• Apply to weeds at the 1-3 leaf stage – efficacy will be more variable as the weeds get bigger
• Apply to actively growing weeds
• Use a residual partner

It is important to remember that germination of grassweeds will also be subject to local factors and the information provided by GEM should supplement but not replace field monitoring.

Learn more about Broadway Star  

Q. What nozzles should be used for an autumn application of UNITE or Broadway Star?

A. For Autumn applications of UNITE and Broadway Star, CFF, VPFF and Defy nozzles are recommended. In the spring Broadway Star can be applied using CFF, VPFF, Air-inclusion and Twin fluid nozzles.

Q. Can I apply a BYDV insecticide in tank mix with UNITE?

A. If BYVD is a concern for you this season it will be beneficial to know that UNITE + Adjuvant + residual partner is compatible with the following BYDV insecticides: Cypemethrin EC, Decis Protech, Fury 10EW, Hallmark Zeon, Karate 2.5 WG, Mavrik, Sumi Alpha. For more information on compatibilities refer to www.dowagro.com/uk/tankmixsummaries.htm

Q. What cultivations are required before establishing OSR following an application of UNITE?

A. There are no cultivation restrictions prior to sowing following crops. It should be noted however that following a sequence of UNITE + metsulfuron-methyl or florasulam, treated ground should be ploughed to a depth of 15cm before establishing OSR.

Q. How can I control volunteer beans in winter wheat?

A. Spitfire* is an ideal solution for the control of key broad-leaved weeds including volunteer beans in winter and spring wheat, barley, oats, rye and triticale and can be applied from GS13. UNITE and Broadway Star also have activity against volunteer beans. 

Q. What is the current use up period on Doxstar, Grazon 90 and Pastor, and what is the position for these products next year?

A. Grazon* 90 (MAPP No. 13117), Pastor* (MAPP No. 11168), and Doxstar (MAPP No. 11063) all now have a phase out requirement as follows:

• The sale and distribution of existing stocks will end on 30th June 2013
• The disposal, storage and use of existing stocks will end on 30th June 2014

There are new Annex III authorisations already in place for all these products.

Doxstar and Grazon will be replaced by Doxstar Pro (MAPP No. 15664) and Grazon Pro (MAPP No. 15785)  – new formulations and updated labels.  Pastor will continue but with some minor label changes.

More details on these new approvals will be conveyed to you over the coming months.

Dow Shield^† (MAPP 14984) is now approved on linseed, broccoli/calabrese, cabbage and cauliflower. Ring Hotline for details. An updated label will be available on our web site shortly.

Subscribing to Dow AgroSciences' Agronomy Update & Pestwatch gives eligibility for 1 Crop Protection BASIS Points annually. Please include course name "Agronomy Update & Pestwatch" and the number "CP/24531/1213/g" on your training record. These details apply until 31st May 2013.

If you require any further information please contact our technical Hotline on 0800 689 8899 or your local Dow AgroSciences representative.

Dow AgroSciences supports the safety and efficacy of its products for tank mixes shown as Physically and Biologically Compatible, but does not warrant the efficacy of other tank mix partners.

Use plant protection products safely.  Always read the label and product information before use.
For further information including warning phrases please refer to the product label.

* Broadway, Doxstar, Grazon, Kerb, Pastor, Spitfire and UNITE are trademarks of Dow AgroSciences LLC.
^† Dow Shield is a trademark of the Dow Chemical Company
All other brand names are trademarks of other manufacturers for which proprietary rights may exist.

Broadway Star contains pyroxsulam and florasulam
Dow Shield contains clopyralid
Doxstar contains fluroxypyr and triclopyr
Grazon 90 contains clopyralid and triclopyr
Kerb Flo 500 contains propyzamide
Pastor clopyralid, fluroxypyr triclopyr
Spitfire contains fluroxypyr and florasulam
UNITE contains pyroxsulam and flupyrsulfuron-methyl-sodium

More information can be found at www.dowagro.com/uk