Tuesday 9 August 2016

Chafer Grub damage is bad, but wait until the badgers arrive.........


Chafer grubs under the soil


The latest generation of Chafer Grubs are now feeding on grass roots.
Over the last few weeks I have visited sites where small Chafer Grubs are feeding just below the grass surface. In some areas they can be found in very large numbers.





At first it seems they are not doing any damage, but eventually the grass will start to go yellow and if you pull away at the grass, it will come away in your hands where the root system has been eaten away. Lawns and grass areas with stronger root systems will survive longer, but even they are overcome by large numbers of Chafer Grubs.

Chafer Grub damage
The damage, at first, can look like an area of grass that is suffering from drought, but once you look underneath you will found no roots and the presence of small white grubs in a c-shape. these are the grubs or larvae of beetles, often the May Beetle. These beetles normally start flying in May and then start to lay eggs in the soil beneath the grass. Over the next few months they develop into larvae and start feeding on grass roots. This feeding continues until the soil temperature drops, this then triggers them to sink lower into the soil and remain dormant until next spring. Rising temperatures then bring them out of dormancy, they then feed, pupate and then become adult beetles. 


Badger damage
However, the worse damage is often not caused by the Chafer Grub, but by what it attracts to your lawn.
Badgers love feeding on Chafer Grubs, which you may think is a nice form of pest control, but the damage they do is even worse!
They rip up lawn areas, tearing at the grass to eat the Chafers underneath. I have visited quite a few golf courses and large gardens which suffer terribly from this damage.
The products available for controlling Chafer Grubs are also reducing, especially for the home gardener.



A close up of a nematode
It is not all bad news though.There is an effective, natural solution.
The use of nematodes against Chafer Grubs can be very effective and now is the time to use them.
These tiny, eelworm like creatures are watered into the turf. They then move under the soil to infect and kill the Chafer Grubs ( the same species also kills Vine Weevil Grubs) . They are harmless to humans, pets and wildlife, but deadly to soil borne larvae like Chafer Grubs. Once infected the Chafer Grubs die within a few days.


There are a couple of rules to follow - 


  • Chafer grub nematodes only work when the soil temperature is over 13C ( late summer/early autumn)
  • Moisture is needed to help them move through the turf.
  • Heavy infestations will need applications in August and again in late September ( the second application targets more mature larvae that the first application may have missed)
  • Garden Chafer traps for catching adult beetles, can also be put out and used in the spring. By catching the beetles, this reduces mating and egg laying, while notifying gardeners that chafer grubs will follow later in the season.
Dragonfli supply Chafer Grub Killer packs to treat all sizes of lawns from 20m2 to 1000m2.

So now we have controlled the Chafer Grubs with nematodes,  there are just Leatherjackets to worry about, but that is another blog.......

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