| Garden
chafers and to a lesser extent cock chafers and summer chafers have been
responsible for the total destruction of a number of lawns in Norfolk,
particularly in parts of Norwich. These grubs are the larvae of “May Bugs” which
as the name suggest are in their adult phase in May/June every year.
The chafer
grubs live just below the turf surface feeding on grass roots. The chafers
particularly favour sandy soils and are most frequently found in damaging
quantities in older, thatchy, compacted lawns. |
Chafer Grub - Scotts
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Adult Garden Chafer - Scotts
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Female adult cock chafer - STRI
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The damage they cause is twofold. Firstly
through the direct feeding on grass roots the grubs effectively disconnected
the turf from the soil surface. The weak patches becomes very prone to
drought and are likely to be invaded by moss and weeds as the grass becomes
less competitive. Secondly, when populations of grubs become high, predators
such as foxes, badgers, hedgehogs and birds come in to feed on the grubs
ripping up the already weakened turf in the process.
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| Chafer grubs
go through various stages in their life cycle before they become the adult
beetle. These stages may take more than a season to complete, hence there may
well be populations of chafer grubs at all stages of the year, they may cause
more or less direct damage depending on the season, in the winter they tend to
be less active and go down in the soil profile and are most active in the late
summer early autumn. In the last few years
controlling these beasts has been very difficult due to the withdrawal of a
pesticide that was known to work well. A new product has become available in
2006 but, it will be a few seasons before we can see how effective this
product will be. |
Scotts |
| We will recommend that all customers in high risk
areas treat their lawns in May to prevent the build up of this pest and so
reduce the risk of having to re seed the lawn at some point in the future.
The new
product will act best on the smaller stages of the grub. Thus it will be
advisable to plan to treat the lawn for at least two seasons to reduce the
population. After that it might be possible not to treat every year. However, if
you live in a high risk area you will be exposed to annual infection and so it
may be best to treat every year as a precaution.
From work done in the USA we know that
the new product will work best if the grass is watered post application, so
if possible arrange to have a Water Tractor or sprinkler handy.
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