| dc.description.abstract | In cereal production plant pathogens cause yield losses, and management strategies for controlling them are important. Cover crops as a part of the cereal production have beneficial properties for the soil health, can increase the biological diversity in the fields, and the soil structure can be improved, additionally cover crops can reduce soil erosion. Therefore, this thesis argues that implementing cruciferous plants as part of the cover crops have the potential to reduce plant pathogens. Cruciferous plants used as cover crops have shown to reduce plant pathogens survival both in laboratory and field plots. The suppression is due to the volatile glucosinolate (GLS) and isothiocyanate (ITC) content cruciferous plants. As a part of a project at NIBIO Ås, an in vitro experiment with allyl ITC were done to look at the effect on survival of Heterodera avenae, Fusarium graminearum and Microdochium nivale, with increasing allyl ITC concentration. Also, a closed jar experiment was conducted to look at the effects of cruciferous plants on suppression of survival of Heterodera avenae and Fusarium graminearum.
The aim of the in vitro experiment was to see at which concentrations of allyl ITC that suppressed fungal growth of F. graminearum and M. nivale and hatching of the cereal cyst nematode H. avenae. The EC50-values of the F. graminearum isolates 200 630, 201 196 and 202 058, were 6.36, 9.50 and 7.62 mg/L respectively. EC50-values of M. nivale isolates 200 136, 200 231 and 202 786, were 8.60, 10.83 and 10.27 mg/L respectively. For H. avenae, the EC50-value was at 5.66 mg/L. This demonstrates a differentiation of EC50-values between nematodes and fungi, but also between fungal species and fungal isolates.
A closed jar experiment was conducted to see if incorporation of cruciferous plants in soil may affect the survival of H. avenae and F. graminearum. Two different time exposures in jars with either two or eight weeks of exposure in jars, were performed. After treatments in jars, the cysts were given either a diapause or no diapause treatment. The total number of eggs and J2 were significantly lower for cysts exposed for eight weeks in jars compared to two weeks, but the total number of eggs and J2 were almost equal for diapause and no diapause. The number of hatched J2 (15°C) for cysts with diapause treatment had significantly higher number of J2 than no diapause treatment. Also, the number of hatched J2 were significantly higher for two weeks exposure in jars compared to eight weeks. The mycelial growth from F. graminearum on oat spikelet incorporated in soil with plant material was not different from untreated. | |
