Latest news with #ShayPhelan
Agriland
10-06-2025
- General
- Agriland
‘Getting to grips with herbicide-resistant grass weeds a priority'
The challenge of herbicide-resistant grass weeds continues to grow on Irish tillage farms at an alarming rate. Meanwhile, the prospect of a significant decline in the availability of herbicide chemistries needed to deal with this problem becomes ever greater, according to Teagasc tillage specialist, Shay Phelan. Recent months have seen Blackgrass declared a noxious grass weed by the Irish government. But this is only the tip of a fast-growing iceberg. Glyphosate resistant Italian ryegrass populations have also recently been identified in Ireland for the first time. Phelan said: 'Getting to grips with herbicide resistant grass weeds within crops is a priority now. Growers can't afford to wait until next season and hope to use a chemical at that stage. 'Such an approach just won't work. The only way to tackle the issue is to ensure that mature seeds are not allowed to be produced this year. 'Options here include spraying areas of crops that have heavy weed infestations with glyphosate or hand rogueing, if feasible. But these jobs must be tackled now.' Crucial to all of this is farmers being able to identify the various weeds within crops at their various growth stages. Phelan explained: 'These critical grass weeds can produce large numbers of seeds that will reinfest your land if no action is taken. 'Control measures include marking weed patches, preventing seed return through hand rogueing or spot spraying, and, for severe infestations, whole cropping or spraying off. 'Delaying these measures until after seed set will lead to costly, long-term consequences.' Mature grass weeds are easier to spot when they are flowering or have visible seed heads. Herbicide-resistant grass weeds Teagasc has quantified the scale of the threat now posed to Irish tillage by herbicide-resistant grass weeds. Italian ryegrass represents an increasing threat with 81% of suspected populations confirmed resistant, necessitating zero-tolerance and strict biosecurity. The plant has flattened spike heads with awned spikelets on opposite sides of the stem. According to the Teagasc tillage specialist, Blackgrass is not present on every farm. However, cases are cases are rising. Resistance has been confirmed in 63% of suspected populations, necessitating a zero-tolerance and strict biosecurity on the part of growers. The plant has compact, slender spike heads with brown or purple-tinged awned spikelets. Spring wild oats is a common, competitive grass weed with loose panicle, large spikelets and bent awns. Herbicide resistance has been confirmed in 34% of suspected populations. Growers should hand-rogue herbicide escapees to prevent resistance development.
Agriland
06-06-2025
- Health
- Agriland
Tillage: Irish wheat crops and the threat of yellow rust
The jury is still out on whether or not wheat crops grown in Ireland this year have succumbed to a yellow rust genetic breakdown, as seems to have been the case in the UK. According to Teagasc tillage specialist, Shay Phelan: 'The yellow rust issue is being investigated at the present time. 'Whatever the outcome of the work, it seems safe to conclude that the growing of wheat will become a more expensive operation into the future.' Meanwhile, the Agricultural and Horticultural Development Board (AHDB) in the UK is advising farmers not to rely on the current yellow rust disease resistance information published in the organisation's recommended list (RL) information sheets. Unusual activity was first seen in late March in an RL fungicide-untreated trial near Sunderland in the north-east of England. At this site, several varieties had yellow rust symptoms despite being classified as resistant to the disease at the young plant stage on the RL (2025/26). Paul Gosling, who manages the RL at AHDB, said: 'Following discussions with plant breeders, we suspected that an important yellow rust resistance gene – Yr15 – had potentially been overcome. 'We subsequently observed similar resistance-breakdown patterns more widely in RL trials, starting in southern Scotland before spreading down the eastern coast of England, down as far as East Anglia.' Trial operators sent diseased leaf samples from the affected RL trial sites near Sunderland and Berwick-upon-Tweed for analysis by the AHDB-funded UK Cereal Pathogen Virulence Survey. The National Institute of Agricultural Botany (NIAB)-led service confirmed that Yr15 gene had failed. Pathogen isolates from these samples not only infected a test variety known to carry the Yr15 resistance gene but went on to sporulate profusely. NIAB-funded work using molecular markers also confirmed the presence of the Yr15 gene in several of the varieties impacted at the young-plant stage. The initial tests prioritised testing of varieties with a strong level of adult plant stage resistance (disease rating 8 or 9), according to RL 2025/26. These tests found that the Hard Group 4 varieties KWS Dawsum, LG Typhoon and Champion carry the Yr15 gene. NIAB is currently testing a wider range of varieties, with further genetic screening also being done by the John Innes Centre in Norwich and the Global Rust Reference Centre in Denmark. The Yr15 resistance gene, which was discovered in the 1980s, confers broad-spectrum resistance against genetically diverse yellow rust isolates (from a large worldwide collection of more than 3,000) and was an important line of defence. Gosling added: 'Adult plant resistance has clearly taken a knock, but the full impact will depend on a myriad of other resistance genes, which vary from variety to variety. 'Some varieties appear to be fighting back, whereas others are recording unusually high disease levels.' 'Although we have not seen the unusual symptoms towards the south or the west, it appears to be spreading fast. 'No doubt it will impact on variety choice and disease management across the UK next season.'
Agriland
22-05-2025
- Climate
- Agriland
Has the rain come too late for some spring barley crops?
The rain that has fallen earlier this week in the southeast will have, undoubtedly, have helped spring barley crops in the region. Teagasc tillage specialist, Shay Phelan, spoke to Agriland about the impact of the lack of rainfall across the island recently on spring barley crops. Phelan said: 'March-sown barleys have fared quite well. But later-sown crops have been hit by the full impact of the dry weather. 'Trace element deficiencies are a real issue in most spring crops at the present time.' Phelan advises that the future management of these crops should reflect the yield potential that now exists. He said: 'On the plus side, the dry weather has reduced the disease threat impacting on crops. 'As a consequence, many barley fields may only require one fungicide treatment this year. 'However, it is now apparent that the heavy dews of the past week or so have predisposed spring wheat and oat crops to mildew attack.' Trace element deficiencies can be brought about in one of two ways: inherent mineral shortages in the soil; or transient deficiencies brought about by period of extreme, dry weather. 'In the case of weather-related deficiencies, crops will respond between five and seven days after rain of a substantial nature has fallen,' Phelan explained. 'But the jury is out on how much of crops' initial yield potential has been impacted by that stage.' According to the Teagasc agronomist, reducing stress levels within cereal crops must remain a priority. 'This is especially so when applying plant growth regulators to spring wheat and oat crops at the present time.' Potato and fodder beet crops have not been affected by the recent dry spell, to any great extent. Here, according to the agronomist, the issue is getting effective weed control measures in place. 'Contact herbicides so not work well under very dry conditions,' Phelan commented. 'However, beet crops are growing very well at the present time. They have responded to the warm, dry conditions.' Potato blight on-farm events Meanwhile, Teagasc will host two on-farm potato blight events next week. The first will take place near Goresbridge in Co Kilkenny on Wednesday, May 28. The second event will be held the following day at a venue close to Duleek in Co Meath on Thursday, May 29. Full details of venues and timings will follow. Teagasc agronomists remain very concerned about the growing levels of fungicide resistance within blight populations and the impact this could have on the Irish potato sector. Confirmation of the potato acreage sown out in Ireland this year will be forthcoming over the coming week or so.
Agriland
10-05-2025
- Climate
- Agriland
Tillage farmers need rain to maintain crop growth
Tillage farmers need rain over the coming days to maintain crop growth rates. But this is only part of the story. According to Teagasc specialist, Shay Phelan: 'Potato and beet growers will be spraying contact herbicides on their respective crops over the coming days. 'And rain will be required to allow these chemicals do their work. 'Some rain is expected over the coming days. But I am not sure if it will be enough to meet crop and farmers' requirements at the present time.' Met Éireann is forecasting more unsettled weather in certain parts of the country through Sunday and the early days of next week. After that, high pressure will take control once again. The current dry spell has succeeded in reducing the disease threat within most cereal crops. But there is one very obvious and significant threat to this rule-of-thumb – yellow rust in winter wheat. 'Varieties such as Thorpe and Spearhead are very susceptible to the disease,' Phelan explained. 'And it's very much a case of farmers walking their fields now and checking the bottom leaves of their crops. 'If yellow rust is present, it will quickly spread to the upper canopy where it can wreak real havoc in terms of final yields, if not treated as a matter of priority. 'It is critically important to deal with yellow rust before flag leaf emergence.' If there are live pustules on the leaves, then the Teagasc advice for growers is to consider applying tebuconazole +/- Comet to give 7-10 days control until the flag leaf fungicide application is due. Potato crops Meanwhile, the jury is out as to the area of maincrop potatoes planted out in Ireland this year. Phelan said he hopes the final figure is down on last year, as potato prices have dropped over recent weeks. 'The last thing that growers need is for a glut of potatoes to be overhanging the market later in the season,' he said. 'My clear advice to farmers is to only commit to the potato acreage that matches the customer outlets they actually have. 'Speculative growing is in nobody's interest.' And, finally, the 2025 Teagasc crops open day is planned for Wednesday, June 25 at the Teagasc Crops Research Centre in Oak Park, Carlow. This year's event will cover the latest research on all the main tillage crops and horticultural field crops. It will also include a major machinery demonstration, with a particular focus on sprayers and the technology available for more accurate applications.
Agriland
30-04-2025
- Health
- Agriland
Yellow rust and mildew an issue in winter wheat crops
Up to this point, yellow rust had been identified in winter wheat crops, growing in the north-east of the country. But now the problem has been tracked south with growers in the midlands confirming the presence of the disease. 'And we can add mildew to the list of disease challenges now confronting wheat growers across the country,' Teagasc tillage specialist, Shay Phelan confirmed to Agriland. 'At this stage, Teagasc is advising growers to inspect all of their fields now and to manage each on a bespoke basis. 'Taking a blanket approach and treating all winter wheat crops in the same way is not the way forward under current circumstances.' According to Teagasc, outbreaks of yellow rust occur occasionally in certain prone varieties of wheat. The disease can be controlled at the Leaf 3 timing with triazole-based and SDHI fungicides. Mildew is most evident in dense, susceptible varieties of wheat on older leaves. It appears as white pustules on the leaf. Mildewicides are very active on wheat mildew. Growth phases Turning to spring barley, Phelan confirmed that most crops are going through their growth phases at a fair rate of knots. 'Magnesium and manganese deficiencies are now apparent in many crops. Growers should take steps to address these issues with immediate effect,' Phelan continued. 'With the month of May beckoning, spring barley crops will be striving to reach their maximum growth potentials.' Later sown crops of spring barley will also be prone to Barley Yellow Dwarf Virus (BYDV). Teagasc research is delivering new insights into the challenge posed by BYDV for Irish tillage farmers. Specifically, the work is confirming that extremely complicated processes are at play, all of which are associated with the relationship that develops between aphids, the virus they carry and the host cereal plant. And each link in the chain has a number of factors that can work through to the final impact – if any – that BYDV can manifest within a crop. E.g., there are different forms of the BYDV virus, with differing capabilities of interfering with crop growth patterns. In addition, the timing of the initial infection and the stage of plant growth can have a key impact on subsequent crop performance. This is why sowing times are so critical in terms of the disease pressure that cereal crops are exposed to. But in terms of practical advice to farmers, the route one BYDV prevention measure comes back to sowing date. 'March-sown spring barley crops will not need an insecticide to control BYDV; it's too early in the season,' Phelan advised. 'On the other hand April-sown crops, will, invariably, require an insecticide to control the issue. 'Where autumn sown crops are concerned, the late-early scenario also kick-in, but this time in reverse. Later sown crops are less exposed to the threat posed by aphids. 'And, of course, all of this comes down to grower choice. Some farmers may not wish to use an insecticide under any circumstances,' he added.
