The latest generation of Chafer grubs are now feeding on grass roots. Over the last few weeks I have visited several sites where small young 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 once you pull 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 will be overcome by large numbers of Chafer grubs.
The damage at first can look like an area of grass that is suffering drought but once you look underneath you will often find 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 grass roots.
This feeding continues until the soil temperature drops, this then triggers them to sink lower into the soil and go dormant until next spring. Rising temperatures then bring them out of dormancy, they then feed, pupate and then become adult beetles.
However the worse damage is often caused not by the Chafer grub but by what it attracts to your lawn.
Badgers love feeding on Chafer grubs, which you might think is a nice natural form of pest control but the damage they do is even worse! They rip up lawn areas, tearing back 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.
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. They are harmless to humans, pets and wildlife but deadly to soil borne larvae like Chafer grubs (the same species also kills Vine weevil 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 and early autumn) and need some moisture to move through the turf and soil. This means watering the grass before application and after.
For heavy infestations it is sensible to do one application in August and another in late September. The second application targets more mature larvae that the first application might have missed.
Dragonfli supply Chafer Grub Killer packs to treat all sizes of lawns from 20 square metres to 1000 square metres.
There is also a Garden Chafer trap for catching adult beetles that can be put out in the spring. This will help notify that Chafer grubs will follow and help reduce numbers , by catching the beetles this will help reduce mating and egg laying.
So we have controlled the Chafer grubs with nematodes , only Leatherjackets to worry about now but that is another blog…..