May 20th, 2021
The critters destroying golf courses
Ban on chemicals is leading to immeasurable damage to greens and fairways
Words: David Adair
These evil little critters called leatherjackets, once controlled using the chemical chlorpyrifos, are running riot. This organophosphate pesticide used on crops and other settings to kill several pests, including insects and worms was banned in 2016. Unfortunately, the ban has left golf courses powerless to control the leatherjackets.
Crane flies lay their eggs in the ground, and on hatching the larvae proceed to feast on the roots of the grass. The small grubs, viewed as a tasty morsel by birds and small mammals, also lead to them pecking or digging up the surface to get at the leatherjackets.
Ironically one of the reasons the chemicals were banned was that they also killed the predators of the leatherjackets. As millions of the little critters were exterminated so the number of predators fell. The resurgence in the larvae numbers has not been matched by that of the animals and birds that feast on them.
The problem has been exacerbated by the wet autumn and dry spring. The loss of root structures has led to less moisture being sucked up the grass leading to boggy conditions during the winter months.
Some chemicals can be used but only in limited circumstances, but there is a more environmental solution, the use of nematodes.
Nematodes are tiny microscopic worms commonly found living within the soil, which will attack soil-borne insect pests with no harmful effects on earthworms, plants, animals or humans, making it an environmentally friendly solution.
The problem is that nematode treatment can be expensive and can only be carried out at certain times of the year.
One hands-on treatment that greenkeepers may adopt for their greens is to cover an area with thick plastic sheeting that blocks the light overnight. The leatherjackets, thinking it is night-time, come to the surface and stay there. Then, on removing the plastic in the morning, the grubs can be disposed of.
A less abundant but potentially more devastating friend of the leatherjacket is the chafer grub. Chafer grubs are the larvae of the chafer beetle and they do similar damage as they too feed on the roots of the grass.
What makes chafer grubs the more significant problem is that animals such as badgers and foxes will rip up the turf to get at a potential meal causing colossal damage. The writer can testify to this as part of his lawn at home was ploughed up by foxes.
The treatments for chafer bugs is similar to leatherjackets with the use of nematodes, again the best but expensive solution.
Having played a few courses of late that all have leatherjackets it is clear that this is becoming a plague on a considerable number of golf courses. Greenkeepers are struggling as fairways deteriorate and members start to grumble and complain.
Hopefully, the predators will start to come back in number soon but one fears that this is a problem with us for quite some time.