As grass cuts reach their lower summer heights, Bayer’s Technical Manager, Dr. Colin Mumford explains that while this might please club members, it’s important to point out the stress that this height reduction inflicts on turf. 

“Daily cutting is a key stress factor and will generate increased susceptibility to disease.  Heat, drought, cold and intense ultraviolet light from the sun are also some of the other factors contributing to turf stress,” says Colin. 

Anthracnose and Red Thread – pictures courtesy of the STRI.

He adds that it’s important to clarify here that the plants won’t necessarily be more likely to get disease; however if there are disease pathogens within the turf already, the stress will make the grass more susceptible to the effects of infection. 

“Some courses will be trying to maintain a grass height of just 2mm over the summer. This obviously increases stress due to daily mowing. Coupled with that, the minimal grass leaf surface area prevents the plant from photosynthesising efficiently,” Colin explains.

“In a plant of this height, there will be fewer chloroplasts within the leaves and therefore less chlorophyll to photosynthesise; ultimately weakening the plant.”

An important and relevant consideration during the mowing season is the need to keep mower blades sharp. A sharp blade will result in a clean cut, which essentially provides a minimal area of damage. Daily cutting will blunt blades quickly and blunt blades are more likely to tear the leaf rather than providing a sharp, clean cut. Colin points out that this creates a jagged edge which results in a larger area of wound. 

“Much like our own skin, this creates a larger area for infection to enter, which ultimately increases the likelihood of disease spread.”

Player demands mean that this particular early summer turf activity is unavoidable and while it does impose stress, it needn’t be a problem at all. Just bear in mind that being particularly alert to early disease signs is important in order to prevent problems further down the line.  If disease is present, a fast acting fungicide such as Interface ^® may be appropriate to control the disease and reduce the stress on the turf.