Potato crops that have been held in check by the cold weather areexpected to put on a surge of new growth after any rain or irrigation whenconditions warm up. But a rapid expansion in the leaf area will stretch theprotection of blight fungicides, at a time when risk is likely to significantlyincrease, warns Syngenta Technical Manager, Stephen Williams.
He advocated growers and agronomists should be looking to utilise themovement of Revus fungicide into expanding leaf growth, to offer extendingprotection from infection between applications.
New leaf growth is especially susceptible to infection, advised MrWilliams, partly since the soft tissue is easier for the pathogen to infect,but also because it is unprotected by conventional contact fungicides.Furthermore, their efficacy is reduced over time after each application.
Revus will move with the expanding leaf to offer protection of the newsurface area. It is also highly effective at maintaining protection betweenapplications.
Revus is proven in trials as the leading blight fungicide for protectionagainst foliar infection. Maintaining a clean leaf in the early stages isessential to prevent disease developing later in the season, as well asstopping transfer of blight to tubers, added Mr Williams.
Mr Williams pointed out that new criteria for foliar blight predictionon the Syngenta website BlightCast service had already indicated the potentialfor infection in the crop this season. The forecast triggered potentialinfection periods at lower temperatures, believed to be more representative oftodays more aggressive blight strains.
BlightCast provides afree localised forecast for growers and agronomists, based on both traditionalSmith Periods and the New Criteria, to help with better timing and selection ofappropriate blight fungicide programmes.