Integrated plant disease management in spring barley and oat production. | Integreeritud taimekaitse kasutamine odral ja kaeral.

Efficacy of the fungicide tebuconazole was tested in two treatment regimes in three spring barley and four oat varieties belonging to different resistance categories in years 2003–2005, the effect of fungicide on fungal contamination of harvested barley grain was tested in 2004–2005 and the effects of four fertilizer doses and two variants of chemical treatments on fungal disease infection and yield of two oat varieties was tested in 2006–2008. All experiments were carried out at Jõgeva Plant Breeding Institute. The impact of the fungicide on the control of major barley pathogens Pyrenophora teres and Cochliobolus sativus and oat pathogens Pyrenophora avenae and Puccinia coronata, as well as kernel yield was studied in the field trials. The fungicide treatment had a strong impact on the control of infection of P. teres and increase grain yield. For the more resistant barley genotype, fungicide application had relatively low returns because of the much higher level of biological resistance and small disease-related yield reductions. There were no single solutions for timing of the fungicide application on oat. Depending on the weather conditions, better efficacy in disease control or higher economic return was achieved from fungicide use at flag leaf stage or at heading stage. The significant differences in levels of disease infection and grain yields between fertilizer and chemical inputs and oat varieties were observed. The infection level of oat diseases and yield increase resulting from intensive fertilizers with pesticides were mostly influenced by the yearly weather conditions. It was found that the fungicide and genotype factors contributed to the variance seen in fungal contamination. The time of fungicide application had clear effect on the incidence of phytopathogenic fungal species. The results illustrate the possibility of use of fungicide and variety resistance based disease control strategy for reduction of seed contamination by fungal spores.