Modelling the effectiveness of Integrated Pest Management strategies for the control of Septoria tritici

Reducing reliance on pesticides is an important global challenge. With increasing constraints on their use, in recent years there has been a declining trend in pesticide use for arable crops in the UK. But with increasing disease pressures and global demand for food, there is a greater need for effective measures of pest and disease control. These circumstances highlight the need for widespread adoption of sustainable alternative control measures. Integrated Pest Management (IPM) is one such solution, comprising a set of management strategies which focus on the long-term prevention, detection and control of pests, weeds and diseases. While many of these methods are acknowledged to offer effective control, their implementation has thus far been limited in practice. As a case study we considered Septoria tritici blotch (STB) (Zymoseptoria tritici), an economically important disease of wheat. We used epidemiological modelling techniques to investigate the potential of different IPM control strategies (crop residue burial, delayed sowing, variety mixtures and biocontrols). Combining existing data with a deterministic, compartmental infectious disease model of STB transmission, we simulated the implementation of an IPM regime into the STB disease system. We investigated the outcomes on disease prevalence and crop yield when comparing conventional and IPM control regimes. In a single field, for the individual implementation of IPM measures we found the starkest difference in potential yield outcomes between delayed sowing and biocontrols (greatest yields), and crop residue burial and variety mixtures (lowest yields). We also found that the collective use of IPM measures has the potential to offer individual growers comparable control to a standard fungicide regime. For a multi-field setting, representing a community of crop growers, a high proportion of growers using IPM can reduce the level of external infection incurred by the growers who maintain a fungicide regime. Author SummaryWith the UK Government seeking to reduce the environmental risk posed by pesticides, the agricultural industry is under increasing pressure to explore alternative methods of disease control. One such alternative method is Integrated Pest Management (IPM), which consists of a variety of management strategies for long-term prevention, detection and control of crop diseases. In our study, we simulate the potential outcomes of using IPM for the control of Septoria tritici blotch, a common disease of wheat. Our results suggest that a regime of IPM control methods may offer growers comparable yields and disease control to conventional fungicide treatments. Furthermore, in a wider system of crop growers, a higher proportion using IPM can reduce the level of infection incurred by all growers in the system, including those who do not use IPM. These findings can offer insight to crop growers who are considering the use of IPM, and to policy-makers who are interested in encouraging its uptake, by validating and quantifying its effectiveness relative to current standard practices.