Biological management of fusarium head blight and mycotoxin contamination in wheat
Project Code: BPI07-110
Allen Xue - Agriculture and Agri-Food Canada.
To evaluate the efficacy new biocontrol strains against Fusarium, determine optimal timing of biocontrol agent applications, monitor the effect of the tested treatments on levels of Fusarium toxins in crop, and provide documentation to support value package for potential submission to PMRA
Summary of Results
Fusarium head blight (FHB) (Fusarium graminearum) is the most important disease of wheat and responsible for over $1 billion losses to agricultural industries in Canada. Current management of this disease problem relies on fungicides to sustain the productivity and quality of grains in most wheat production areas. Tebuconazole is the only fungicide registered for the control of FHB in Canada. Considerable efforts have been made by most wheat breeding programs aimed at FHB resistance development across North America. However, resistance breeding has not been productive, and cultivars with high levels of FHB resistance are not yet commercially available. There have been increasing concerns expressed by the public about environmental contamination, food safety issues, and human health problems resulting from widespread use of pesticides in agriculture and food production. Hence, there is a need for improved FHB management systems that will reduce fungicide use.
The goal of this project was to evaluate the efficacy of new biocontrol strains against Fusarium, as alternatives to chemical pesticides for control of FHB in Canada. Tests were conducted both in the lab and under a simulated epidemic environment in the field to determine the effectiveness of 20 different bioagents (15 bacteria and 5 fungi). In the lab fungal growth in the presence of potential antagonists was evaluated in dual culture. In the field experiments researchers considered the reduction to the FHB index, the fusarium damaged kernels and the presence of mycotoxin (a dangerous side effect from infection).
ACM941, a strain of Clonostachys rosea, was the most effective bioagent, When sprayed onto wheat heads, ACM941 significantly reduced the FHB index by 46.4%, the fusarium damaged kernels (FDK) by 29.0%, and the mycotoxin in grains by 28.7%.
An enhanced effectiveness was observed when ACM941 was combined with a low rate of Tebuconazole in the reduction of infected spikelets (IS), but not for other disease parameters. ACM941 was better than Tebuconazole in reducing the production of F. graminearum, in the lab, but was less effective than the fungicide in reducing the FHB index, fusarium damaged kernels, and mycotoxin in the epidemic field environment.
Under the natural field conditions where the FHB disease pressure was low, ACM941 significantly reduced the FHB index in both no-till and conventional tillage systems. The effects were not significantly different from that of the Tebuconazole fungicide used as a positive control of the experiment.
When used as a seed treatment applied to the Fusarium -infected seed, ACM941 significantly increased emergence by 10.0% and yield by 9.9%, which were less but not significantly different from those of the untreated control with the non-infected seed.
On the average of nine cultivars with different levels of FHB resistance, ACM941 reduced FHB index by 50.0%, percentage of infected spikelets (IS) by 24.3%, fusarium damaged kernels by 34.8%, and mycotoxin by 18.6%.
Results of this research project suggest that ACM941 is an effective bioagent that has great potential for commercial use in the control of FHB in wheat production. The bioagent can be used alone as an alternative to the fungicides or in combination with a low rate of the fungicide for a pesticide reduction strategy in an integrated disease management program. Further research on this promising organism is supported by PMC under project codes BPI08-020, BPI09-040, BPI09-050 and BPI09-070 (to facilitate the development of a commercial product).
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