Maize growers now have a valuable opportunity to increase yields, reliability and crop quality through the control of key leaf diseases, with the full approval for the new Quilt Xcel fungicide from Syngenta.
Quilt Xcel is the first fungicide approved for the two most common and increasingly prevalent leaf diseases affecting UK maize, Eyespot and Leaf Blight (Helminthosporium). The impact of leaf diseases that result in early die-back of plants can severely affect yields of forage maize and feedstock for biogas production.
Enhancing maize plant health and protection of the green leaf area ensures the crop can make more effective use of sunlight to boost cob yield. Yield improvements of over 15% have been seen in trials from the control of Leaf Blight alone.
Crucially for growers, trials have repeatedly shown that the use of Quilt Xcel causes no delay to cob maturity, ensuring crops can be harvested at the same time as normal – but with significantly higher yields compared to untreated crops affected by disease.
The label recommendation for Quilt Xcel is for one application of 1.0 l/ha, at any time from stem elongation (GS 30) through to the end of flowering (GS 69).
Systemic movement within the plant will ensure both fungicide actives – azoxystrobin and propiconazole – are distributed throughout leaves to offer effective disease protection and long lasting results.
Syngenta Maize Field Technical Manager, Simon Roberts, advocated that, for best results, application should be as late as possible through the flowering period, to minimise the impact of later occurring diseases. If early symptoms are identified, however, early intervention will protect uninfected plants and prevent further spread of the leaf diseases.
“In practice, application timing is going to be dictated by the physical ability to spray in tall plants as the crop grows. Syngenta application trials have shown best practice is to spray using the angled Syngenta Defy Nozzle, alternated to face forwards and backwards along the spray boom,” he advised. “The aim is to get all-round coverage of the plant and the optimum retention on the leaf.”
Operators should also look to shield sharp protrusions on the underside of machines and to adjust forward speed, so as to allow taller plants to push down and spring back without damage, he added.
Maize disease risks
When conditions are right for Eyespot it is the most damaging leaf disease for maize crops, warned Syngenta Maize Portfolio Manager, Wouter Keppens. In cool and wet seasons, infection can cut the maize growing season by several weeks, at a time when plants should be putting on the maximum cob grain fill.
“Experience in the UK in 2011 demonstrated the epidemic potential of the disease,” he reported. “There were instances of crops being harvested early, with warnings of limited forage supply and quality on farms.”
Trials in Denmark had shown a 75% reduction in severity of Eyespot infection on leaves from a single Quilt Xcel. NIAB trials inoculated with Eyespot after application had seen a 15% increase in Dry Matter (DM) yield with Quilt Xcel, compared to untreated.
In the UK Eyespot most typically occurs in the south and west, but can occur anywhere during wet weather. First infection can occur from early 2nd leaf growth stage, but is not usually seen until later in the season, added Mr Keppens.
The disease overwinters on old infected crop debris, with new spores spread by rain splash and on the wind the following season. Eyespot is endemic in traditional maize growing areas, but as the area of maize grown in the eastern counties for AD biogas expands, the background level of infective disease spore release is expected to increase each year.
Northern Leaf Blight has been identified in the UK relatively recently, however climatic conditions and the increase in industrial maize cropping is expected to see the incidence worsening over coming years, said Mr Keppens. “Wet soils and damp leaf surfaces in humid conditions appear most conducive to rapid infection; initial spots can spread by over 1cm in just 24-hours, leading top rapid leaf loss.”
Early infection at or before flowering can result in up to 50% yield loss, but if leaves can be kept clean for six weeks post flowering any late infection will have little or no effect on final yield.
Mr Keppens highlighted that whilst Leaf Blight in itself does not give rise to harmful mycotoxins, research has shown infections can make plants more susceptible to other fungi capable of producing mycotoxins, including Fusarium and Aspergillus.
“Maize growers need to be looking at all aspects of crop agronomy and whole Crop Solutions to counter the threat of diseases, including rotation; cultivations; crop nutrition; varietal resistance and integrated fungicide applications,” he advised.
“The launch of Quilt Xcel in the UK gives them the chance to counter damaging leaf diseases and ensure the crop has the chance to reach its full potential, for both forage maize and biogas energy production.”