Arable
Fungicide performance and disease management in wheat, barley and OSR At the Agronomists Conference 2021, Jonathan Blake, technical director of crop protection at ADAS, ran through the results of the 2021 fungicide trials conducted primarily by AHDB and ADAS with assistance from the wider fungicide working group. Rachel Hicks reports.
Table 1 shows the various agro-chemicals and their modes of action in wheat and barley that AHDB tested in 2021, and Mr Blake drew attention to two relatively unknown names on there, including Myresa (mefentrifluconazole), the new azole which BASF recently launched, commonly known as Revysol (also available as a co-form with fluxapyroxad in Revystar XE). The other he mentioned is Peqtiga (fenpicoxamid), which is also known as Inatreq – one of the active ingredients in Univoq, the new QII fungicide launched by Corteva in spring 2021. He pointed out that both Myresa and Peqtega are registered as solo products, but it’s not advised to use them that way, and commercially they are only available in a twin pack with a partner product, to be used with other modes of action. See Graph 1 for a summary of their efficacy as a protectant at various dose rates. In the graph on the right hand side, it shows the products with a single active ingredient, while on the left hand side it’s the Table 1: Wheat and barley – registered products Product Arizona* Proline Myresa Imtrex Elatus Plus Comet Peqtiga Ascra Xpro Elatus Era Revystar XE Univoq Barley only Siltra Kayak
Active (s) folpet prothioconazole mefentrifluconazole (revysol) fluxapyroxad benzovindiflupyr (solatenol) pyraclostrobin fenpicoxamid bixafen + fluopyram + prothioconazole benzovindiflupyr + prothioconazole mefentrifluconazole +fluxapyroxad fenpicoxamid + prothioconazole
Mode of Action Multi-site DMI (azole) DMI (azole) SDHI SDHI Qol (strobilurin) QII SDHI + SDHI + DMI SDHI + DMI SDHI + DMI QII + DMI
bixafen + prothioconazole cyprodinil
SDHI + DMI Anilinone-pyrimidine
*Arizona tested at 100% dose only.
Active (s) prothioconazole azoxystrobin + difenoconazole bixafen + prothioconazole boscalid mepiquat chloride, prohexadione calcium + pyraclostrobin boscalid + pyraclostrobin difenoconazole azoxystrobin dimoxystrobin + boscalid
mixes. The data compares quarter, half, full dose, up to double rate. Arizona was tested at a single 100% dose for comparison. Both of the mixes performed very well, so it is *No label recommendation for light leaf spot control but may be applied at the appropriate time, for the control of other diseases. hard to separate them based on that data. effective at controlling net blotch, while Testing the same products in terms of their mefentrifluconazole (in Revystar) added good curative ability, everything tended to perform efficacy against ramularia. The SDHIs fluopyram less well. Mr Blake warned you should be careful and bixafen (in Ascra Xpro) added useful activity when interpreting curative data though, as there on net blotch. are often numerous infection events that will have occurred prior to leaves being sprayed, and on many occasions, they may have a level of septoria that’s Fungicide performance in OSR already beyond control. So, in terms of curative data, Architect and Shepherd have only just been it’s not an absolute value – more just a measure of registered for use in OSR – see Table 2 for a full how products compare. list of OSR products tested. Shepherd (boscalid + In terms of yellow rust trials, Elatus Plus and pyraclostrobin) has a full label dose of 0.8-litres/ha, Imtrex provided the best control among the with the same total dose per crop. single actives at lower dose rates, while Elatus Era Architect (mepiquat chloride + prohexadione performed best in the mixes, which suggests it calcium + pyraclostrobin) has a full label dose of would have a role to play in geographical areas with 2-litres/ha, with a total dose per crop of 4-litres/ha. a high rust problem. Mr Blake also suggested that In terms of differences between products, for yellow rust control is just as much about timing as it phoma stem canker, they are quite small. OSR crops is about the specific products used. are quite tolerant of canker, so there is little benefit In the 2021 trial, Elatus Plus and Myresa were from applying more than 50% of full label rate as most effective on brown rust and Proline the least, part of a two-spray programme, with an average while in the mixes, Revystar XE was slightly stronger yield response of only around 0.3t/ha. than Univoq, although both were effective. For light leaf spot, azoles and non-azoles provided There’s a new addition to the barley toolbox, a similar level of disease control and yield, but the with Asca Xpro being newly registered in April/May use of different modes of action (azoles/non-azoles 2021 for use in barley. It has a different full label rate in sequence or in mixture) is vital for resistance for barley, at 1.2-litre/ha, and a total dose per crop of management going forward. FG the same 1.2-litre/ha rate. Graph 1: 2021 Overtrials – Septoria Protectant (6 trials) In terms of rhyncosporium, Use Imtrex and Myresa only in mixtures with at least one fungicide with an alternate mode of action that has as a protectant Imtrex out efficacy against the target disease performed the rest, followed by Myresa 25 25 Proline, Revystar XE and then Revystar XE Proline 275 Univoq Imtrex Ascra Xpro. However, as an 20 20 Arizona Arizona eradicant, Ascra Xpro performed best, although Revystar and 15 15 Imtrex weren’t far behind and 10 10 Proline brought up the rear. Net blotch and ramularia 5 5 were also tested against, 0 0 with prothioconazole and 0% 50% 100% 150% 200% 0% 50% 100% 150% 200% Percentage of full label rate Percentage of full label rate fluxapyroxad both being Disease %
Wheat and barley
Product Proline Priori Gold* Aviator Filan* Architect Shepherd Plover Amistar Pictor
Disease %
Mr Blake began by explaining that the AHDB Appropriate Dose Network was started around 27 years ago, and has been championing independent information on fungicides, looking at both efficacy as well as appropriate dose. The team has been testing various products at sites across the UK, located in the higher disease risk parts of the country. The products have been tested over a range of different spray timings, to give relevant protectant and curative data.
Table 2: Oilseed rape products
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