The past few weeks have been a hive of crop-related activity with numerous open days and visits taking place. On the adjoining page, Stephen Robb looks at information on varieties that are coming on stream via the recommended list system and others that are in the pipeline. In this article, I report on crop condition and disease pressures from the different events and on the recent observations at Teagasc trials on SDHI performance.

This might be regarded as a relatively low-pressure year given that we had spells of dry weather that helped slow the progress of septoria. As a result, most crops with good well-timed programmes are quite clean of septoria. There has been some disease movement in recent weeks in some crops but hardly enough to heavily affect yield potential.

Septoria moves against SDHIs

At the recent Teagasc Crops & Cultivations open day, growers got a chance to see potential emerging problems for control of septoria using SDHIs. At a number of recent field workshops, Dr Steven Kildea showed trials where SDHI actives were used alone in plots for experimental purposes. Their efficacy was noticeably down on previous years and this was happening at sites where the level of a moderately resistant isolate of septoria was present at high levels.

This asked the question as to whether this isolate would adversely affect field performance? The answer was clear and unambiguous. The presence of high levels of this moderately resistant isolate significantly decreased the performance of SDHI actives alone. This is a worrying development but it was also inevitable. However, this finding was confined to trials where only SDHI actives were used and where they were used alone. The performance of mixtures in well-timed programmes was still solid.

The fact that the level of this moderately resistant septoria isolate is increasing all around the country is, therefore, worrying. However, the use of good sensible mixtures in combination with chlorothalonil continue to perform well at sites where this isolate is present at high levels so field control is still possible, Steven emphasised. The challenge is to manage treatments carefully so as to minimise the risk of allowing any further isolates to develop at field level.

Timing is everything. Another trial which applied a fungicide mix on each leaf from leaf-four onwards found that either a leaf-three or leaf-two spray, followed by a leaf-one spray had resulted in the lowest level of septoria on the crop. The standard recommendation is leaf-three and leaf-one but a five-day delay on the leaf-one timing may have given the leaf-two spray an advantage (relative to the later flagleaf timing) at this site.

Steven emphasised that their results will be examined with scrutiny to formulate sound fungicide advice for 2018. But the game has changed once again and he said that it is up to every grower to do all they can to minimise disease pressure. This means some combination of later planting and better variety septoria resistance.

Looking at similar trial at UCD sites the story was broadly similar. However, the level of fall-off in the performance of straight SDHI products was much less obvious. Still there were patches in many of these plots that would give cause for concern that the level of resistance was building.

It is possible that the level of resistance will be higher initially at intensive trial sites but this will spread to commercial fields sooner or later. There remains considerable variability in septoria populations and pressures at local level.

Goldcrop days

Goldcrop had two excellent days recently, one in Dunleer and the other annual event on John Dunne’s farm in Shanagarry, where there was a good test of varieties, old and new. One thing that hit me between the eyes was the level of septoria on Rockefeller in Cork. This is a relatively septoria resistant variety but it was badly infected, especially in comparison to Costello beside it, which is only moderate on septoria.

John commented on the importance of timing in this regard. He said that he timed the fungicide on the varieties relative to Costello, which was sown around the trials. While the importance of timing is unquestioned, I wondered if I was looking at breakdown in the variety resistance because this difference was not obvious at other trial sites. Whatever the reason, the potential pressure from septoria at this site continues to support the identification of reasonable variety resistance.

During discussions at both sites, the ever restricted access to chemicals was discussed. At Dunleer, Mairead McGuinness MEP talked about the ever increasing resistance among consumers to pesticides and she said that this will only increase.

The subject of BYDV also came to the fore and while many may wish for access to Redigo Deter for use on spring cereal crops, its continued use on any crops may be the more important question.

SeedTech

This year, many farmers and trade members were given the opportunity to visit the new SeedTech and DLF seed processing and distribution facility just opened in Belview port in Waterford.

This is a state-of-the-art 52,000ft2 facility processing high-quality cereal and grass seed, along with premium grains for the food industry. It represents a significant investment for the future of the agricultural sector.

The SeedTech trial site near Ballymountain acts as a research facility for variety testing and it is also used by Syngenta for pesticide evaluation.

This site is also a hot bed for septoria but some combination of weather and fungicides helped to keep treated plots looking quite clean. Untreated plots were a different story though and disease was rife.

There were many new varieties on show which showed considerable promise. Varietal septoria restance continues to be evaluated at this site and progress is tangible.

Syngenta also showed very good performance from Elatus Era on all crops.

Drummonds

Different years bring different pressures and septoria was not so bad at Drummonds open evening in Co Louth. Here, the unsprayed wheat variety plots took on a different appearance as yellow rust ravaged them since before Christmas. Having lower septoria pressure did not result in a lesser dependence on fungicides on many farms in this region this year.

But, like the other sites, well-treated plots were very clean and showed great potential.

There were terrific winter oilseed rape trials at this site and a raised view over the plots showed the variability in height and maturity.

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