Each year, lawn grubs hatch in spring and munch on your grass roots during spring and summer where they can't be seen, systematically destroying your lawn. By the time you are aware of them, there are large patches of brown or missing grass in your lawn and it can look like it is slowly dying.
This is because your grass roots have deteriorated to the point where they can no longer provide water to the grass and worse, birds start to dig up your lawn in search of the grubs.
Come summer, this is when you see most people popping down to the hardware store to buy various poisons to kill the grub, but there is an ecological alternative that is actually cheaper, safer and lasts longer. Entomopathogenic Nematodes (EN for short) will do a better job for longer and do it safely and naturally. And without killing other living organisms in your soil.
The fabulous thing about ENs is that you don't have to keep pets, bees or birds off your lawn while it is being treated and of course they aren't poisonous so they pose no threat. EN’s are also only interested in lawn grubs (are very host specific) so won't kill anything else.
According to Ecogrow, Nematodes work by infesting the lawn grub with their symbiotic bacteria. The bacteria kills the host and breaks down its tissue into food.The ENs then reproduce every 10-14 days and keep reproducing until they run out of food (your lawn grub). Once the grub has reduced substantially, your lawn will recover as new roots grow. Your lawn should then be free of lawn grubs for a couple of years.
ENs were originally identified by Dr Robin Bedding from CSIRO in Australia, developed over a 30 year period. The CSIRO EN technology is the first technology that Ecogrow has commercialized. ENs are the second most widely used biological control worldwide. In 1999, CSIRO Entomology negotiated with a number of groups interested in commercialising the technology. After negotiations with CSIRO, Ecogrow was appointed licensee of the technology and took over the business of marketing the nematodes as a standalone company and they are now sold around the country through Ecogrow.
This Queensland lawn has been using ENs for around 5 years and is an excellent example of good value - both for the cost of actually keeping lawn grub at bay and time. Imagine having to reapply poison every 6 weeks instead of every two years to an area of this size.
It's pretty clear from this picture why the Ecogrow team sell a lot of product to golf courses!
If you have persistant grub, speak to people like Ecogrow as they have a number of ecological applications and you may need a different bug.
It is good practice when you lay new turf to treat it for lawn grub. Often new turf brings grub with it and introduces it to the grass you already have growing.