Integrated Disease Management

The application of a range of hierarchical methods, commonly utilising several methods in combination as part of a routine grounds’ maintenance programme to control turfgrass diseases. The term is often shortened to the acronym IDM.

Prevention of disease in the first place is what good turf management practices will aim for and this can often be achieved through effective cultural practices. The disease triangle identifies the three requirements needed for disease attack to occur: a pathogen (i.e. presence of the disease, typically as spores), a suitable host, which is a turfgrass species that is susceptible to the relevant pathogen, and suitable environmental conditions, especially moisture, in which the disease can rapidly spread. Controlling moisture is arguably the main key environmental condition that can be managed to help prevent disease outbreak in the first place. Other factors such as pH and nutrient status - either excessive or insufficiency, as well as stress placed on the grass plant due to usage and mechanical activities, and shade conditions, will also be contributory factors. Good management practices will be looking to minimise the contribution these conditions have in encouraging a turfgrass disease attack.

Physical and mechanical control should be carried out to maintain a sward and soil environment that produces a more competitive environment for a turfgrass to thrive in. So, good aeration of the soil and surface, reducing any thatch build-up by scarification, cleaning out the base of the sward through scarification and verticutting to ensure good air flow throughout the grass leaves and basal areas. Brushing of a sward to remove surface moisture and monitoring soil moisture content, as well as potential-evapotranspiration, to control irrigation inputs. A curative action to a disease attack might be the application of a fertiliser, for example, Nitrogen to help reduce the effects of Red Thread disease, as well as mowing and the boxing off of clippings to avoid or reduce any further spread of the disease.

Biological control might be achieved through the use of a biopesticide. These are currently of limited availability in the UK, but one example (in 2026, but which is due for being withdrawn on 7th February 2027) is Harmonix Turf Defense, which contains the active substance Bacillus amyloliquefaciens strain QST 713 and acts on contact with a diseased plant. It might help reduce the incidence of Anthracnose, Dollar spot, and Microdochium patch.

Indirect contributions to reducing disease incidence might be achieved through the use of biostimulants, helping to reduce plant stress by improving plant growth and development conditions. A biostimulant doesn’t attack a pathogen, so might not be considered a biological control, but rather a cultural control.

Chemical controls will be focused on applying a curative fungicide where the disease has already attacked the grass plant and needs controlling, or the application of a preventative fungicide which is applied when conditions seem likely to favour a potential disease attack. Chemical control is often considered the last line of defence against disease, however, where preventative treatment is undertaken this is then the first line of defence.

Setting an acceptable maximum level, or threshold, of disease content within a turfgrass area is an important first step in the process of IDM. However, due to the often rapid spread of some diseases, the need for allowing for an increase in base line thresholds where the disease is permitted to be present for a defined period of time above its base line value, before being controlled back to its maximum desirable level, or more realistically acceptable level because very few managers would desire even a very small content of disease within a turfgrass surface due to its potential to spread extremely fast given the right conditions. A useful guide to helping determine what might be a suitable threshold is through the use of performance standards. These provide pre-set values, which can be adjusted to suit local needs, for different quality levels for sports pitches, as well as for amenity grass areas.