What are chafer grubs?
Chafer grubs are the larval stage of the chafer beetle. They are easily recognised having white/cream bodies, a brown head and six brown legs. They are usually curled into a C shape in the soil under turf and are quite large - approximately 1-2 inches in length.
The female chafer beetle burrows into grass turf and lays eggs in summer. The larvae pupate over winter and hatch as adults in late spring.
Chafer grubs will survive mild winters, but if the temperature drops too much and the soil freezes, they simply burrow deeper into the ground for hibernation.
How do chafer grubs destroy grass?
Chafer grubs will feed on the roots of turf weakening the grass, turning it brown in patches and making it very easy to pull up.
Secondary predators like birds, badgers and foxes often exploit this weakened grass to rip it up and eat the grubs underneath. This further damages lawns and grassed areas often meaning a full re-seed is required once the problem has been eliminated.
Churned up grass and bare patches in lawns are often the first indication of a grub infestation. If you see this disturbance, simply remove a section of turf to see if you can see the grubs underneath at root level.
Using nematodes to control chafer grubs
Nematodes are a living microscopic worm that will seek out the chafer grubs and kill them. The nematode Heterorhabditis bacteriophora is the specific type needed to kill chafer grubs.
These naturally occurring nematodes infect their hosts by entering through natural openings or the cuticle. Once inside the grub, they release symbiotic bacteria, which quickly kills the chafer grubs.
The nematode will then leave the grub and seek out another one to infect. Heterorhabditis bacteriophora continue to breed giving long lasting control.
This biological control method offers a natural and environmentally friendly approach to pest management and is safe for humans, pets and the environment (children and pets need not be excluded from treated areas).
Applying nematodes
Nematodes are a highly effective alternative to chemical control. They can be used in an organic pest control programme and can be easily applied through a sprayer or a watering can with any filters removed.
Start by aerating your lawn creating spaces for the nematodes to penetrate the soil. Nematodes are supplied as a powder and need to be diluted with water before use. Follow the packet instructions for dilution rates or see more information on our product page.
Nematodes can be used on all plants and crops in mild, humid conditions as long as the soil temperature is between 12-30ºC, so avoid using them until temperatures have risen enough to warm the soil. Autumn months are usually ideal.
If you treat nematodes for the first time in spring, you may need to treat them in autumn too. Speak to our technical team for more information.
Nematodes should be used immediately after receipt. If not applying the same day, they will need to be refrigerated and used within two weeks. To store in refrigerated conditions, simply remove the outer packaging to ensure good air circulation around the tray(s).
Check soil moisture levels before applying nematodes; they are living organisms and need moisture to move through the soil. Water the area thoroughly the day before applying if needed.
Find out more about ordering and applying nematodes for chafer grub control here.
