Question
It is now fall in Canada and just realized we have grub worms in our lawn.  The birds have been tearing our lawn apart to get to the grub worms.  What can we do now with the cold season upon us.

Answer
Canadians have a new Grub Pest problem for their Lawns.

Twentieth-Century Turfgrass didn抰 worry about the European Chafer ('Rhizotrogus majalis' to scientists) -- not in Canada, at least.  European Chafers weren抰 noticed until 2001 in Lawns in New Westminster, British Columbia.  The scary part: The Grubs of this Beetle don抰 stop at Grass.  When they抮e REALLY hungry, they抣l add Shrubs and Flowers to the menu.

Other Grubs don抰 do that.  Some are guilty of merely negligible damage, at most, to Lawns.  But in parts of Canada, the larvae of this brown-bodied Beetle is the Grub to worry about.  Because it does the most damage.

Now, I don't know what part of Canada you live in, Claire, or even what Grubs you are actually growing, but I do know that they抣l be harder to locate as days go by.  Ground level Soil is just too cold for them.  They MUST head to China to survive the season.  Which means hungry Birds (or whatever is turning your Turf inside out) will be digging deeper until the ground freezes.

Take a look at the website of Greensmiths.com, a Lawn Care company with one of the slickest sites on Grass-growing.  Greensmiths posts a 'Grub Worms' page: 'The Beetles lay their eggs 1 to 2 inches deep in the soil and the eggs hatch in 2 to 4 weeks'.  In Canada, this happens around July.  What comes next is not a pretty sight: 'Young Grubs begin feeding on Grass roots immediately.'

Let's read that again: 'The young Grubs begin feeding on Grass roots IMMEDIATELY.'

When you run out of Grass, European Chafers expand their diet to foodstuffs smaller, weaker Grubs could only dream of.  Know Thine Enemy.  A little educational bedside reading:

http://www.greensmiths.com/grubs.htm

My advice?  Be afraid.  Be very afraid.  

Major damage? Already done MONTHS ago.  You just don't see it.

Yet.

Those Birds are doing you a BIG favor tearing up the Lawn as they search and destroy those ugly animals, my friend.  Birds may not be your only allies in this predicament, Claire.  When you're not looking, you may be getting visits from Skunks, Raccoons, Moles and other carniverous fauna.

If there抯 anything to worry about, you抣l see it next Summer, when temps rise and roots are missed.  As Greensmiths warns, 'Grubs move deep in the Soil for hibernation just before Winter arrives.  They come back to the root zone and start eating again in the Spring.'

The good news is that since you haven't spiked your soil with Grub-killer, your Birds will live to pick up lunch where they left off when Winter抯 done.

Solutions exist.  Progressive solutions.  Intelligent solutions.

As recently as 2005, the solution was Methyl Bromide -- CH3Br.  Methyl Bromide is illegal now.  This was a deadly nerve gas that would travel on the clothing of users and poison people the direct user came in contact with AFTER s/he was done working with it.

Not Intelligent.

O.K., to replace the Methyl Bromide, there抯 the (outdated) scorched-earth GRAY Thumb approach.  For this, you lace your Lawn with various poisons that weaken or kill a broad group of living things, Grubs included.  Then in the Spring, Birds and their wildlife friends will return in search of fat, juicy, protein-packed Grubs, sifting through the toxic Soil, perhaps eating a few other tainted insects in the process.  They'll get sick, they may die, and the chemicals may alter the DNA of their offspring so badly they don't hatch, or grow up sterile.  That's why that book was called Silent Spring.

Even the Scotts Canada website declares: 'It is normal for all Lawns to have some Grubs present.  4 to 6 Grubs per square foot of Turf probably won't cause any visible damage in a healthy Lawn.'  See that?  NORMAL according to Scotts.  Down here, the discovery of even one Grub in the soil puts most people in a state of panic -- thanks to a lifetime of pro-pesticides advertising.  I'd like to point out by the way that certain words, like 'poison' and 'pesticide', are avoided like the plague in the more recent packaging of these products.  But that's another message for another day.

In the end, Plan A -- Chemical Pesticides -- does not work.  Poison and all, they'll be washed away, and new Beetles will lay new Eggs to do more damage to your Grass.  Only there will be fewer and fewer friendly Bug-eaters on your side.  Pesticides take no prisoners, and they don't discriminate.  Anything with a nervous system is a target.  Including people and pets.

Let's look at some other options.  Plan B.

Well, you've got friendly Birds and other predators -- as is painfully obvious when you step outside in the morning and survey the damage.  What a party you missed.

But Science is on top of this.  There抯 several cutting edge techniques dreamed up in research labs across the continent.

You may already have a modest population of microscopic Heterorhabditis Bacteriophora ('H B Nematodes' for short), one of 6 species of Heterorhabditis that live in garden Soil.  H B Nematodes target Masked Chafers among other Bad Bugs, wiggling around 7 inches or deeper to find insect larvae to attack.  You can also buy these -- when the time is right -- to water in with the garden hose on early Summer mornings.  They also work on Gypsy Moths, Ants and Termites (see 'Phoresy in Entomopathogenic Nematodes' by Jerry Cates at the Bugs in the News website of EntomoBiotics Inc., an environmental research company and Beneficials retailer:

http://www.bugsinthenews.com/Phoresy%20in%20Entomopathogenic%20Nematodes.html).

Another recent approach may have been blazed at University of Tennessee Dept of Plant Sciences and Landscape Systems.  In 2002, researchers Ryan Noble, Stephanie Harvey and Carl Sams published 慣oxicity of Indian Mustard and Allyl Isothiocyanate to Masked Chafer Beetle Larvae?  For this study, they shot up different Soil samples with Carbon Dioxide, ground up Tomatoes and the leaves of the Indian Mustard plant.  Then they grew Grubs in them.  They concluded that chemicals called 慻lucosinolates?in the Indian Mustard turned into a natural pesticide that could protect plants when you tilled a few tons of it into the Soil.  (The Tomatoes and the CO2 were good controls, but worthless as pesticides.)

Right now, today, what can you do?

Nothing, where Grubs are concerned.  Grubs are too deep to reach with poison, even if you drench your Soil with it Katrina-style.  The Birds will still get stuck, but the Grubs almost certainly will oblivious to any poison that goes in the Soil now.  For state-of-the-art methods of chasing away Grub-diggers, contact an AllExpert in Household Pests and Rodents -- but my guess is you will just be chasing these away until the ground freezes.

But there are some things you can do to optimize your all-out assault next Spring.

You can roll out the welcome mat for Heterorhabditis Bacteriophora.  Make your Soil and Lawn H B friendly.  Susan Mahr, University of Wisconsin at Madison, posts the details on the University of Wisconsin, Madison website:

http://www.entomology.wisc.edu/mbcn/kyf611.html

Mahr points out, 'When infective juveniles leave the host, they move around in the Soil, searching for a new host to infect. Soil texture, moisture, and temperature all affect dispersal and infection. Heavy Soils impair movement, with less dispersal occurring as the percentage of silt and Clay increases in the soil. These same factors all affect survival as well. Survival (at least in lab studies) is best under moderately low soil moisture and cool temperatures (60 degrees F).'  Do whatever you can to make life easy for the Nematodes.

She explains, 'These [H B] Nematodes occur naturally in soil, but not at high enough levels to provide effective pest control.  Inundative releases are necessary to reduce insect populations below economic thresholds.  In some cases recycling through host insects will occur to minimize the need for subsequent applications.'  

So we know that Nematodes alone will not defend your Lawn from a Grubs attack.  No problem.

Certain Ground Beetles species are WILD about Grubs.  Ground Beetles are fast, and they're Carniverous.  That makes them ALL Lawn-friendly.  Remember that next time you抮e thinking of stepping on one.  Ohio State posts a cheat sheet on Ground Beetles that will make you pause -- perhaps long enough for one to get away:

http://ohioline.osu.edu/hyg-fact/2000/2102.html

Ants are another ally here.  Worker Ants hunt all over for unhatched Grub Eggs and baby Grubs.  Purdue University scientists watched the work of Ants through Plexiglas to measure just how many Grubs they can eat.  'Up to 73 percent of White Grub Eggs in the Soil were taken within a 72 hour period and Ants were found to be the predominant predator. One species of Ant, Solenopsis molesta, proved to be the primary ant predator of White Grub Eggs in Turfgrass.'

Yes, it is very hard to be a Grub these days.  Any Grub.

In the Spring, you should patch up your damaged Lawn, perhaps sow anew.  Then take action against the Grubs.  You have a whole Army of solutions for your Grubs problem.  I can go further into this but AllExperts won抰 appreciate the bytes I抦 using up, so let me know if you have any followup q抯 and I抣l tell you what I know.  Thanks for writing.