ALS Contract Services


CASE STUDIES – Chafer Grub Control

Professional Application Using Nematodes – A Form of Biological Control


Client :
Ashburnham Golf Course – Carmarthenshire

Brief Summary


Ashburnham Golf Course is located close to Burry Estuary and Worm’s Head in the South West of Wales. The Amateur Home Internationals have been held there several times as well. It is a superb 117 year old links course that drifts seamlessly into the neighbouring sand dunes. Harry Vardon a Jersey professional golfer who won the Open Championship a record six times and also won the U.S. Open said that it was “The course I like best in Wales”.


Ashburnham Golf Course has been experiencing problems with Chafer Grubs since the beginning of 2011 – Paul Hopkins, the Head Greenkeeper, returned from holiday to discover a sight that he’d been dreading discovering. They had experienced problems in the previous two years in the rough areas of the course; however this was the first year that the problem had moved out onto the fairways. In previous years it had simply been a matter of repairing the damage caused by predators seeking an easy lunch. At one stage 48 magpies were dispatched over a 6 day period. However this didn’t resolve the problem and Huw Morgan, the Golf Club Manager, had to resign himself to removing the food source of the predators.

There are six species of Chafer Grub in the UK: the Welsh Chafer, Summer Chafer, Brown Chafer, Cock Chafer, Garden Chafer and Rose Chafer. The most familiar being the Cock Chafer or ‘May bug’, a large beetle that can be heard as a low droning noise on pleasant spring evenings. The grubs feed on the roots of grasses and other plants, their presence can be detected by the yellowing patches that it creates in turf. Chafer Grubs can be found in the soil under the loose turf. They have stout white bodies curved in a C shape, light brown heads, with three pairs of legs and darker patches at the base of the abdomen. They are bigger than the adult beetles although their size varies according to species, 8-35mm. They live within the soil for up to 3-4 years going through various ‘instars’ as they develop. The real damage to turf is done by predators such as starlings, rooks, crows, jackdaws, magpies, foxes and badgers that make the most of an abundant high protein food source lying just beneath the surface.

Huw Morgan, the Golf Club Manager at Ashburnham, has many years of experience as the Course Manager at The Wildernesse Golf Club in Kent. Huw became aware of the problem and appraised the options that were available to him. Huw contacted Ray Hunt, a technical advisor at ALS, qho has 34 years extensive experience in golf course management at both links and inland courses with six PGA European tour events including two British Masters. Ray was able to recommend the application of nematodes. The ALS Contracts team has applied biological control methods such as nematodes extensively and effectively on previous jobs. The species of nematodes, Heterorhabditis megidis, is host specific and only feeds on white grubs such as Chafers.

In the early hours of a September morning the nematodes arrived on site in 100 x 500g trays, each containing 250,000,000 nematodes. Providing the soil is sufficiently moist to allow the nematodes to move within the soil, the nematodes seek out the Chafer Grubs and attack the pest by entering natural body openings. Once inside, they release bacteria that stops the pest from feeding, quickly killing it. The nematodes reproduce inside the dead pest and release a new generation of hungry infective nematodes, which disperse and search for further prey. Whilst on site ALS Contracts were able to ascertain the level of infestation recording 144 grubs per square metre.

ALS contracts are acknowledged specialists in the application of pesticides. The water volume rate of 2000 litres/hectare was used in conjunction with a wetting agent to ensure that sufficient numbers of nematodes were applied to come into contact with the Chafers. This volume of material applied over 15 hectares of the course required two specialised spraying rigs. The operatives started at 6.30am and completed the task that day without impacting upon a society playing later that day.

Huw Morgan worked hard to communicate the problem to the club membership and what would be required to resolve it. The membership, although understandably frustrated by the damage caused by the Chafer Grubs, understood that the problems were beyond the abilities of the green staff to control and responded positively to Huw’s request to deal with the problem. Having such wonderfully firm fescue greens in such a beautiful location and have the course damaged by an agent outside of their control was an exasperating time for Huw and his team, however the problem was resolved thanks to some inventive thinking and the support of ALS Contracts.

Huw recently cheerfully related that he’s had no further problems with Chafer Grubs and states that he thinks that this is due to the application of nematodes applied in 2011.

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