Performance Story: An on-farm approach to evaluate the interaction of management and environment on Fusarium Head Blight development in wheat
Christiane Catellier, Indian Head Agricultural Research Foundation
Fusarium head blight (FHB) has become a substantial management concern for wheat growers in Saskatchewan, affecting both yield and quality of the crop. An integrated approach to FHB management is recommended, including the use of resistant varieties, a timely fungicide application, and crop rotation, along with other cultural practices.
FHB development in the crop is dependent on environmental conditions and FHB forecasting tools have been developed to predict the risk of disease development based on local and regional weather. In commercial production, the effectiveness of mitigative management practices undoubtedly varies with environmental conditions. Thus, improved disease management can potentially be attained with a better understanding of the interacting effects of management and environment on FHB development in wheat. The objective of this study was to examine the effects of multiple factors simultaneously, utilizing a multivariate perspective, with data obtained from fields under commercial production.
A field-scale observational study was conducted in collaboration with local producers near Indian Head, Melfort, and Scott, Saskatchewan, from 2018-2020. Environmental and agronomic data were collected from several sample sites in several fields throughout the growing season, and management data was provided by producers. Data was collected for a total of 91 fields from 12 different operations over the three seasons.
First, individual effects of each management and environmental variable on FHB symptoms in the field (FHB index), Fusarium damaged kernels (FDK), and deoxynivalenol (DON) level were examined. Then, a multivariate analysis using a multiple regression and competing models approach was conducted to assess the relative influence of each variable and the interactive effects of different combinations of management and environmental variables on the level of FDK.
Results showed that the choice of cultivar and fungicide product were highly influential on FHB development. The timing of fungicide application was not as influential as would be expected, but this was likely because fungicide was applied at the recommended timing, prior to anthesis, in nearly all the fields. Environmental variables affecting the development of FDK in the crop during pre-anthesis stages were mainly related to temperature, while influential variables during post-anthesis stages were related to moisture. The effects of environmental variables did not appear to be additive, but rather entirely interactive with management.
More importantly, results showed that recommended management practices were in fact highly effective for FHB mitigation, however their effectiveness was also highly moderated by environmental conditions. FHB risk management practices are nearly always applied in fields under commercial production. Thus, these findings confirm that in order to advance our ability to forecast the risk of FHB infection using predictive models, it will be necessary to more thoroughly evaluate the interactive effects of management and environment. Based on the results of this study, it would be most insightful to compare genetic FHB resistance or effectiveness of different fungicide strategies (products and timing) as a function of various environmental conditions.
The study was also useful in demonstrating the potential of on-farm observational studies, and validating a systems approach to agronomic research.