Saturday, 15 September 2007

Grubby goings on in the park

Crows and Magpies dig the holes (© I hope to take a close up picture of a Lenton crow as soon as I can.

Damage to Lenton Recreation Ground Bowling Green, 12 September 2007

The Chafer Grub, which eat the grass roots causing bald patches to appear.

My wife Susan has a fridge magnet which reads 'Do you want to speak to the man in charge or the woman who knows what's going on'. By the time I explain the relevance of the fridge magnet to my story, there is a good chance that you will be ahead of me!

In my blog dated 19 August 2007 about the last Park Consultative Group meeting, which caused a bit of a stir, I wrote:
In the last few weeks or so bear patches have appeared on the greens and when you consider how much rain we have had in recent months, the problem is clearly nothing to do with too much dry weather. To a layman like me, this seems like a matter which needs attention sooner rather than later.

In my naivety, I assumed the growing number of bald patches on one bowling green in particular was due to overuse and that the green it was happening to was being over used because the other bowling green had been 'claimed' by at least one of the newer bowling clubs, so ordinary and more casual users were being given 'Hobson's Choice' — thus causing more wear and tear on one bowling green. At the meeting, this, innocent observation led us into a discussion about car parking.

Last Wednesday morning I did not know that Chafer Grubs existed. By late-evening I was an expert, thanks to Dave, our Groundsman, and the web. Now for the bit about Susan's fridge magnet. Change the word 'man' to 'officer' and 'woman' to 'worker' and, as you will instantly appreciate, all could have been revealed at the park meeting a few weeks before and we would never have got onto the subject of car parking.

Instead of two officers who didn't pick up on my concern about 'the bear patches' and what might be causing them, a worker would have immediately twigged what I was upon about and explained how the Chafer Grub larvae are a common turfgrass pest in this country and that they have the habit of infesting the same area year after year. They eat the roots of Turfgrass causing the turf to die in 'large irregular patches' (just as my photograph shows). They tunnel under the grass making it feel spongy underfoot (and it does). The holes which then appear in the bear patches are actually caused by birds like crows and magpies who can hear the chafer grubs munching away and moving about, so they dig holes in the earth and take out a tasty meal. The downside for Dave and Simon is a bowling green with lots of holes.

I learnt all the above from Dave. He even took me into his room in the pavilion and showed me a picture of a Chafer Grub (exactly the same as the one I downloaded from the web and have included above) and explained how, because of the park's Green Flag, it would have to be treated without using chemicals. Type 'chafer grub' in the a web search engine like Google and there are thousands of references to this pesky grub. I found out that even Badgers and Moles eat them and that they are 'particularly common on non irrigated turf such as golf course roughs, fairways and ornamental turf'. The latters seems like a good description for a bowling green to me. To the untrained eye, the damage caused appears to be drought stress. The grubs don't like it wet. They have a complete annual life cycle with eggs, larvae, pupae and adults and are best 'monitored using light traps (something else to find out about when I have the time) in August when the grubs are large enough to be seen. Average populations of six grubs per square meter can be masked with water and fertiliser. 10–15 grubs per square meter can cause significant damage in the autumn months' — which suggests the state of the bowling green is going to get worse before it starts to get better.

So, what can you do about them if you don't use chemicals. According to the web there are some natural solutions. I rather like the idea of using a heavy roller prior to the grubs hatching because this 'compacts the soil, thus making movement difficult for the grubs'. Just how to do you find out they are about hatch? The life cycle says 'mid-June', but it seems a bit hit and miss to me, even though I love the idea. By chance, we received a Harrod Horticultural Catalogue in the post yesterday and Susan found an advert for the 'Nematode Heterorhabditis Megidis' which, I assume, eats the grub and should be applied during August and early-September. To treat 'up to 100 sq m' costs £14.95.

There you have it, the next time you look at those bear patches on the bowling green you will be as much of an expert as me and know that the damage hasn't been caused by overuse or even drought, but by a Chafer Grub. If you're ahead of me, as I suspect you are, you will understand why we need a worker at all future Park Consultative Group meetings more than we need two officers if we want to know what's really going on in Lenton Recreation Ground!

Northern Rock Bank branches are besieged by borrowers after they are forced to go to the Bank of England for a loan.

1 comment:

Sarah said...

Hi Robert

Sarah from Advance here, looks like u had a good day at the park today! my blog address is:

Hope u & susan are in good form, it was very nice to have tea at urs, in ur lovely, warm, calm home.

Saw u walkin twds the QMC on Thurs am with ur hat on, while i was on the bus.

bye 4 now x