Worms love wet soil, and their casts are turning our courses into a muddy mess, but don’t give the greenkeepers grief – their hands are tied
You may not believe it but worms are considered the superheroes of soil – so much so they’ve been classified as a beneficial species. They improve soil fertility, break down organic matter and help aerate and improve drainage, improving surface playability.
There are 28 species in the UK and most of them get on with life without ever causing golf courses a problem.
Four, though, are a bit trickier, because they produce casts – the small muddy mess you’ll see on tees, fairways and greens – as they rise to the surface.
The removal of a key pesticide, carbendazim, has left greenkeepers largely powerless to deal with their menace.
What’s more, worms love wet soil that’s why you’ve suddenly seen an explosion of casts causing short term ruin at clubs up and down the land.
“Wormcasts are becoming one of the biggest issues,” said Chipstead course manager Sam Bethell when summing up the recent wet spell.
“It’s perfect for them – nice soft, wet, soil and their castings are absolutely everywhere.
“Brushing (to clear them) is hit and miss because brushing a wet cast just smears it. On our greens and fine turf areas we use a switch cane and it takes man hours and time.
“That’s your morning – you’ve lost half your day just clearing wormcasts from playing areas. That’s without trying to cut.”
Yet it’s not just about them being unsightly, getting stuck in the soles of your shoes, and generally being difficult to control.
If greens teams don’t spend the time getting rid of the casts, they can cause big problems to a shed’s expensive machinery.
Bethell added: “If you don’t knock the wormcasts off, you are going to roll them – creating a smear or flat wormcast.
“That takes up grass space, flattens on top of the grass and kills the grass underneath it.
“Your rollers will get blocked up and it changes your height of cut if your rollers are covered with wormcasts. If they get into the cylinder they blunt the blades.
“If you kill the grass underneath, it’s going to get infected by a weed. And if you’re on a fescue or bent green, Poa annua (annual meadowgrass) is going to invade that space or, at this time of year, disease. It’s just an open pore for disease to jump in.”
Bethell’s team, and greenkeepers everywhere, can try to remove surface litter and clippings to discourage feeding worms.
There is some evidence acidifying the soil can reduce populations but more trials need to be done, while drier conditions are also a deterrent.
But with the extreme deluges set to continue, giving conditions where worms thrive, we’re just going to have to accept some unsightly surfaces.
So next time you step on a wormcast, or are tempted to complain as they invade a green and make your putts more difficult, give your greenkeepers a break. Their hands are tied.