Harmful winter wheat diseases and possibilities for their integrated control in Latvia

Decision support systems based on control thresholds are an important part of integrated disease control systems in winter wheat. Various warning and forecast systems have been developed in different countries (in Latvia – under the framework of Danish-Baltic joint project ‘Development and Implementation of an Internet-based Decision Support System for Integrated Pest Management’), but results were contradictory. The aim of this investigation was to identify the possibilities for integrated disease control under intensive management of winter wheat. Different schemes of fungicide treatment, including a decision support system, were tested in field trials from 2008 to 2012 in two places. Leaf blotches caused by Pyrenophora tritici-repentis and Zymoseptoria tritici are recognised as the most harmful wheat diseases in Latvia. The total impact of diseases, which was calculated as area under disease progress curves, was affected by the year and the scheme of fungicide treatment. Significantly higher yields wer...