Markets, Aphids and grasses discussed at Forum

Teagasc’s recent Crops Forum dealt with many pressing issues, such as variety choice, markets, aphids, rotations and grass weed control. This article provides a short summary of most of these topics.

This annual look at global grain markets pointed to demand as being the major concern for the year ahead – demand is essential to find a use for the big global harvest. There are still uncertainties re total maize production but the wheat harvest has set another global record for the second year in a row.

Market prospects

The prospects remain for a big global harvest and much of the wheat has already been harvested. Big wheat volumes mean high potential exports from central Europe and the EU. John Bergin from R&H Hall indicated that global wheat stocks are at a record high and may increase by nearly 12m tonnes after this harvest to pass 220Mt for the first time ever.

Maize and coarse grain stocks, on the other hand, are set to fall. The major uncertainties remaining are output from the US maize crops and crop planting and performance in the southern hemisphere.

So how does the market react to the biggest wheat harvest and possibly the third-biggest maize harvest ever? It takes a lot of demand to consume this volume of production. Traders are nervous and prices are under pressure as exporting countries seek to buy demand by discounting sales. This is further exacerbated by the big crops in the five major exporting countries.

The Black Sea region has increased in relevance for wheat production and trade. Prior to the mid-2000s, production in the 12 Former Soviet Union (FSU) countries fluctuated between 60m and 90m tonnes. In the past eight years, this has ranged from 80m to 115m tonnes of wheat per annum. So these countries are increasingly important, both in terms of production and export, even though the average yield there is less than half what it is in the EU (2.4t/ha versus 5.7t/ha).

The situation with corn (maize) is broadly similar but current estimates suggest that demand may slightly exceed supply this year. This is helping maize to hold up in terms of price this autumn. Many of the major producers are expected to produce less, but again the FSU countries have come to produce and export more in the past eight or so years (1m tonnes in 2006 and 24m tonnes in 2013). Exports from Brazil also increased considerably over the past decade.

There were two major demand drivers for corn over the past decade – US bioethanol production and feed demand in China. The US bioethanol market has since matured so demand is no longer increasing and concerns about the Chinese economy send nervous signals with regard to demand levels from there.

For these reasons, the global feed grain industry is now looking for demand rather than supply and this implies price pressure. And the demand that is there is being supplied from cheaper eastern European sources where devalued currency is improving competitiveness.

Price pressures

Other factors are also acting against price and demand confidence in this oversupplied market. John referenced the slowing Asian economy and the falling cost of energy compared with a year or so ago. Then there is the influence of fund activity and the fact that this can provide occasional selling opportunities, as was the case in early July last.

There are many political concerns also, such as the export tax regimes in Russia and Argentina, the war in Ukraine, China’s reaction to its economic downturn, the refugee crisis, etc.

Perhaps the biggest impact will come from currency. Our weak euro is currently contributing a €10-€15/t price benefit to eurozone producers. And currency devaluations in Russia and Ukraine in particular are affording them increased competitiveness. John suggested that we may be in a period of strong dollar which could last up to five years.

John reminded us that the September/October period is not a good time to sell grain and yet a lot of our grain is being sold in this window. He asked if growers will continue to plant against a background of low prices and concluded, like the rest of us, that they will.

And for growers elsewhere in the world the, current November ’16 price of €185/t will provide an impetus to growers elsewhere to sell forward now and plant when the time comes.

While high prices quickly cure high prices by incentivising increased production, John reminded us that low prices are much slower to self-correct. This is basically because growers will continue to plant. It takes an unfavourable weather event in one or more of the major exporting countries to turn sentiment when prices are low, John said.

Aphid concerns

There has been a lot of interest in aphids in recent years following:

A few years ago, Teagasc reported that aphids carrying this kdr resistance were found in a limited survey. But these were only a small proportion of the population in Sitobion avenae (Grain Aphid), the main transmitter of BYDV. Since then, other samples were taken in sprayed fields where control proved disappointing. In these samples, the majority of aphids carried kdr, but this might be expected if all susceptible aphids were killed by the two sprays.

Given the recent concerns, Teagasc conducted a new survey of aphids this spring. Speaking on this subject, Michael Gaffney of Teagasc told us that this kdr resistance has, so far, only been found in a single clone of S. avenae (SA3) and that the proportion of this in the population could impact on the efficacy of any pyrethroid spray.

So have things changed? This is the question being asked by the new survey which took place in six major tillage counties. Michael warned that the concern about resistance is mainly associated with BYDV control and so is concentrated around the grain aphid (S. avenae). So the specific identification of this aphid is important for growers.

Michael said that the grain aphid can exist in a range of colours from green to black to red but all S. avenae have long black Siphunculi, which are the pair of little structures that stick out from rear end of the aphid. If these are not black then the aphid is not S. avenae.

Michael said that if a grower suspects a control failure he/she should:

Eamonn Lynch of Teagasc asked if the recent increase in BYDV prevalence is related to the increase in winter barley area, which has increased by 40,000ha in the past four years. Infection risk is further increased by earlier drilling dates, geographical location and the recent mild autumns and winters.

The incidence of BYDV in winter barley in Eamonn’s east Cork region was quite high and he sampled sites across the region to help identify differences arising from sowing date, seed treatment and spray application. And at the end of the day he concluded that all infected sites, except for one late-sown site where BYDV was evident, suffered some level of grain yield reduction.

The greatest yield loss (3.0t/ha) occurred on a continuous winter barely site which was sown on 24 September. Where sowing date was delayed to 5 October and one aphicide was used, symptoms were still very evident but the yield reduction was down to 1.25t/ha. A hybrid winter barley sown on the same day was treated with an insecticide seed dressing and got one follow-up spray in December – the yield loss here was estimated at 0.6t/ha.

One crop sown 25 October was sprayed once with an insecticide and suffered no yield reduction. So, in general, the later crops were planted and the more protection that was used, the lower the yield loss arising from BYDV, Eamonn summarised.

These experiences have resulted in the advice to use an insecticide seed dressing on all winter cereals that are planted early in an area, especially in high-risk areas. This will always need to be followed up by at least one aphicide spray. The use of seed dressing might be considered for medium to late planting also and, depending on the sowing date, these may or may not need a follow-up aphicide.

Where no seed treatment is used with later planting, all crops should be sprayed once with a contact aphicide in November. And if a grower finds that a pyrethroid aphicide has not knocked down a population, the advice is to spray again with a different mode of action using products like chlopyrifos.

Grass weeds

Grass weeds are an ever-increasing problem in tillage systems. Brome is now one of the most spoken about problems because wild oats are virtually ubiquitous. Blackgrass is the great fear arising from the challenges and experiences in Britain. Others include scutch, creeping softgrass, annual meadow grass and rat-tail fescue.

One of the speakers at the crops forum was UK consultant, Patrick Stephenson. Patrick is a very practical man who told us that in his area around north Yorkshire sterile brome is the main grass weed.

Grass weeds are very much a barometer of farming practice. Practices like non inversion and early planting favour many grass weeds and so they proliferate if not controlled in some way. For most growers, grass weed control is about herbicides but, as evidenced in the UK, we are losing this battle. If we are to have a realistic chance of containing any weed we must understand its biology and manage husbandry practices to disadvantage it.

Patrick presented a slide based on recent research which quantified the contribution of different husbandry practices to the reduction in blackgrass levels in a crop. If there is a background black grass population of 500 plants/m2, the sensible use of shallow stubble cultivation can reduce this number alone by 20%, or reduce the weed problem down to 400 plants/m2. If shallow cultivation was followed by delayed drilling (not necessarily late) the blackgrass population would be further reduced by an additional 37%, or down to 252 plants/m2.

The use of higher crop seeding rates could bring a further 30% reduction in this number to 176 plants/m2 and the choice of a more competitive variety could bring a further 22% reduction to 138 blackgrass plants per square metre. This represents a significantly lower challenge to the herbicide used.

With this level of population challenge, Patrick suggested that an effective herbicide might be expected to give 99% control. But to win this battle, any surviving plants still need to be removed.

The combined benefit of all of these complementary practices is capable of bringing control levels to 99.8% but this is not practically possible through the use of herbicide alone.

Panel discussion

A useful panel discussion on the subject of grass weeds emphasised the need to understand the biology of the weeds you are targeting. And you need to target any weed of which there is one plant in a field. Tim O’Donovan suggested that many weeds get out of hand before the grower actually realises what the problem is and that it may have spread significantly by that stage.

Barry O’Reilly from the Department of Agriculture outlined the very high standards associated with Irish certified seed and stated that the industry operates even higher voluntary standards with regard to grass weeds such as wild oats, sterile brome and blackgrass.

He said that a crop will be rejected for seed on the final inspection if plants of any of these are found in the field.

This is creating challenges for the seed industry and John Dalton, who is the current chairman of the Irish Seed Trade Association (ISTA), said that it is getting increasingly difficult to get clean land for certified seed production.

Athy grower Jonny Green told us that he is continuously tackling two specific weeds – sterile brome and blackgrass. Having discovered that a field had quite a bit of blackgrass last year, his immediate reaction was to ensile the crop before it set viable seeds. The major challenge with all weeds is to prevent seed return by whatever combination of actions necessary.

Jonny has been working to improve his soils and the use of catch crops and both min-till and direct drilling have featured in his farming system. He spoke about the need to actively reduce the weed bank through shallow cultivations post-harvest. He emphasised the need to keep this shallow so as not to bury any of the seeds shed.

He also said that ploughing is a useful tool for some weeds but emphasised that the quality of job must be good, with good burial, and that ploughed ground should not be turned up again for a number of years.

“Leaving the seeds buried for longer helps to decrease their viability and reduce the size of the weed bank,” Jonny stated.