The signalling of fungal treatments of oilseed rape against Sclerotinia sclerotiorum and Phoma lingam

Abstract: The infection pressure of pathogens Sclerotinia sclerotiorum and Phoma lingam in the oilseed rape has been monitored at the workplaces in Opava and Šumperk for a long time. The results from 2016 to 2018 confirmed the strong dependence of infection pressure of pathogens on the weather conditions. The lowest contamination of the oilseed rape petals by S. sclerotiorum ascospores was recorded in 2018 and the higher contamination of petals and higher infestation of oilseed rape in 2016. In this year, the infestation of oilseed rape by Sclerotinia stem rot was rare. Higher captures of ascospores of pathogens Leptosphaeria maculans, L. biglobosa (asexual stage Phoma lingam) were recorded at the both sites in September and October 2017. In mid-September 2017, higher precipitation (96.2 mm) was recorded in Opava. In Šumperk was recorded higher precipitation 92.5 mm in September 2017. The month October was temperately higher than the long-term normal (+10.49 °C). In both locations Šumperk and Opava there was measured higher temperature than the long-term in all autumn months. The infestation of oilseed rape stems before harvest 2018 ranged from 80 to 90 percent. The highest effect of fungicidal treatment combined with insecticidal treatment on the yield and the thousand seed weight values was reached in 2018.