Question
QUESTION: Before I get too far... I agree with you on the subject of not using chemical poisons on the lawn to kill grubs. We have a lot of wildlife we enjoy, and attract a lot of birds, but I am exasperated by our grub problem this year. This lawn has never previously been treated with grub killers. We are on a well, so it is not an option anyway.

Normally we have a reasonable amount of grubs in our lawn, with no real damage, but this year has been horrible:

We started off very wet in June with the grass growing like crazy, right around the time the June bugs are having a fiesta around the trees. A few weeks later all of their eggs hatched, and it started getting dry, meaning the grass stopped growing. The grubs kept eating however, and now we have large expanses of dead grass that is completely unattached to the soil. I dug down in a roughly 4-square inch area and counted 10 large grubs, definitely June bug grubs. I tried Milky spore a few weeks ago, and have re-checked the area for sick grubs, but they seem largely unaffected. I would guess that Japanese Beetle grubs are the target of this substance.

Worse yet, the natural predators have discovered them and have turned the lawn into a mine field (skunks). Yes, I enjoy watching the antics of the birds fighting over the grubs, and the over 20 robins at once in a small part of the yard going to town, but the skunks are driving me batty. I cannot mow the yard for all of the grass clumps, and the clumps stay together enough that raking it back doesn't work so well. If I remove the clumps, I have nothing but bare dirt. At least the weeds are going with it.

What I would like advice on is how to repair the lawn, if I should fertilize now that the grubs are extracting all of my nutrients, what my best grass seed (or alternative plant) choice should be, and how to prevent this in the future.


Oh, I am located in Western NY, Canandaigua.

Repair: I have no idea how to chew up this clumps. Is there some device (apart from a rototiller) that may make restoration a bit easier? I have thought of designing a clod chewer-upper, especially for starting new gardens where a rototiller just isn't practical.

Fertilizer: I use millorganite (sp) in the gardens, is this adequate on lawns, especially chewed up ones?

Seeds: Is there a good source for Yarrow seeds? Otherwise for grass these areas are 100% sun, well-drained, sweet soil. They also get very dry in the summer.

Prevention: Milky spore seemed ineffective. Will beneficial nematodes hang around once applied? I would preferably treat once, and then get lazy again. Any other things to try? I figure a spectrum of predators would probably be the most effective.



ANSWER: I'm always happy to help a dedicated organic gardener who puts wildlife first.  You pose some good questions here.  Have a seat.  Pour yourself a cup of coffee.  This is going to take sometime.

The urgency about your Skunks problem I completely understand.  I know nothing about them except that they eat a lot of insects (especially Grubs) and can be hazardous if spooked.  So I will pose your Skunk question to a Skunks AllExpert and see if s/he knows any techniques for keeping them off your property until the Grubs are gone.

The Canada Health Department's Pest Management Agency addresses the Junebug invasion you are experiencing and suggests it might be yet one more effect of Global Warming.

They write, 'The most common White Grubs you抣l find infesting your turf in Canada are those of the native June Beetle or Junebug.  About twenty species live in Canada; all of them are very similar and difficult to distinguish from each other. Two other smaller exotic species, the European Chafer and the Japanese Beetle, have been accidentally introduced into Canada and occur mainly in southern Ontario, primarily in the Niagara peninsula. The European Chafer, however, has recently migrated further north and east, and is responsible for much of the lawn damage in recent years in eastern Ontario. Usually the cold helps to control these pests, but the milder winters lately are partly to blame for an increase in their populations.'

They also say this is something you tend to deal with every 3 years.  They recommend Tiphia intermedia , Pelecnus polyturator and Scoliid Wasps as biological weapons.  They also recommend planting Larkspur and Geraniums during the summer to make the plot hostile to these Beetles.  You can read the whole report at the official website:

http://www.pmra-arla.gc.ca/english/consum/whitegrubs-e.html

I have to question their 'Larkspur-Geranium' solution.  A study in 2002 at the University of Kentucky found such plantings 'ineffective' for repelling Japanese Beetles from Roses:

http://www.bioone.org/perlserv/?request=get-document&doi=10.1603%2F0022-s0493(2003)096[0081%3AECPANH]2.0.CO%3B2

'Interplanting with Geraniums significantly INCREASED numbers of Japanese beetles on Roses. Similarly, Roses surrounded by sachets with fennel seeds, cedar shavings, crushed red pepper, or osage orange fruits had significantly more beetles than the control plants on two or more sample dates.'   I just do not believe companion plantings alone are going to exude that much repellent against most insects.  

On the rest of your comments, there are a few things I should tell you.

Milky Spore Disease -- 'Bacillus popilliae' -- attacks the larvae of Japanese Beetles and their close relatives.  Have a look at the photos on Cornell University's Organic Biocontrol pages.  On one side, a Healthy Japanese Beetle Grub; on the other, one infected with Milky Spore Disease:

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/images/bacillus_popilliae

The Cornell authorities tell us Milky Spore Disease was 'the first insect pathogen to be registered in the U.S. as a microbial control agent.'

But they also point out that the ubiquitous Japanese Beetle "is the EXCLUSIVE host of the strain of B. popilliae which is sold commercially."  Which means you are absolutely right -- it will not affect the larvae of the Junebug, 'Coleoptera Scarabeidae'.

Anyway, Milky Spore Disease does not work overnight even under the best of circumstances.  The 'incubation period' takes so long that I always recommend faster acting methods during the grace period, which can take several YEARS.  If someone with the Flu coughs, you don't keel over with the Flu.  It takes days or weeks and with some diseases months before symptoms appear, and then you have to get sick before you die.  That's how it is with the Grubs.  They are exposed to the Milky Spore bacteria, the germs infect them and multiply, and the Grubs get sick and die.  In between there's Winter, when nothing is going on.

Some authorities are having second thoughts about how reliable today's Milky Spore Disease is.  Some suspect that the targeted larvae may be building some kind of resistance to this disease.  Cornell points out that one Kentucky study indicated the B. popilliae marketed for Grub control were not really that good.  They also observed that even spore-sickened Grubs were inflicting the same damage to roots as healthy, uninfected Grubs.  If true, Milky Spore Disease would be a good way to control adult Japanese Beetles, but of marginal value for dealing with a Grubs problem.

In a study done in 2000, researchers ran experiments to compare the success rate of the most widely used weapons against Japanese Beetle Grubs and the Masked Chafer, Cyclocephala hirta (a major pest in California), including Bacillus thuringiensis (marketed as 'Bt'), Milky Spore Disease, Paenibacillus popilliae, the beneficial Nematodes Steinernema kushidai and Heterorhabditis bacteriophora, and the Weedkiller, Diazinon.  Conclusion: 'Only Diazinon and entomopathogenic nematodes, they concluded, caused 'substantial mortality'; and S. kushidai 'activity persisted significantly longer than Diazinon.'

An abbreviated abstract is posted gratis at the BioOne website:

http://www.bioone.org/perlserv/?request=get-document&doi=10.1603%2F0022-0493(2000)093[0071%3ABCAFWG]2.0.CO%3B2&ct=1

Note that the winner in this Grubs Demolition contest was Steinernema kushidai.

Cornell posts a full page on this celebrated Nematode from Japan, where it lives in the soil:

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/nematodes.html

S. kushidai is just what they doctor ordered, they say, when it comes to curing your House and Garden of all sorts of pathogenic pests.  They LOVE Steinernema at Cornell, calling it 'extraordinarily lethal' for these kinds of applications, way beyond other biologic weapons.  In fact, they say, 'The only insect-parasitic nematodes possessing an optimal balance of biological control attributes are entomopathogenic or insecticidal nematodes in the genera Steinernema and Heterorhabditis.  These multi-cellular metazoans occupy a biocontrol middle ground between microbial pathogens and predators/parasitoids, and are invariably lumped with pathogens, presumably because of their symbiotic relationship with bacteria.'

It gets better.

'Most biologicals require days or weeks to kill, yet Nematodes, working with their symbiotic bacteria, kill insects in 24 to 48 hours.'

Nematodes classified in the Steinernema species are effective against pests ranging from Termites and Fleas to Fungus Gnats.  S. kushidai specializes in 'Scarab larvae'.  

These Steinernema and Heterorhabditis Nematodes are fragile fauna.  Remember that when you acquire them.  Follow directions explicitly.  They can be extinguished simply by being exposed to Sunlight, or if there is insufficient Oxygen, if it is too cold or hot., or if the temperatures change too much, too soon.  Dry soil will kill them.  Handle with care.

Now, the bad news.

Where can you get these Steinernema and their Nematode Friends?

Ohio State posts a page listing commercial suppliers of Insect Parasitic Nematodes:

http://www.oardc.ohio-state.edu/nematodes/nematode_suppliers.htm

Not an S. kushidai in sight.  Evidently this five-star Nematode is not available for sale outside of Japan yet -- or, if it is, it is part of the proprietary Nematode Zoo sold by some of the more secretive merchants.  Browsing down the (somewhat outdated) list of suppliers on Ohio State's list, the most promising for your needs looks like a Canadian supplier, Natural Insect Control:

http://www.naturalinsectcontrol.com/company.html

They may be able to obtain the multitalented S. kushidai if you place a special order, or dissuade you if S. kushidai is not suitable for your purposes (due to climate for instance).  I have placed requests with several suppliers separately and if nothing else the demand will register with them and someone may add it to their line.  And at best, maybe they do include it in some Nematode Cocktail.

Finally, please see this lovely picture of a female American Pelacinid Wasp posted on a website called Jack Schmidling Productions:

http://schmidling.com/insects.htm

This is a scary-looking but benign Wasp that hunts down Junebugs without mercy.  You can often find swarms of this blue-black Wasp flying around the Lawn on a hunt.  The female pokes around in the soil to find Junebug Grubs.  When she finds one, she lays an egg on top of it.  Egg hatches, spends the summer eating the Grub for breakfast, and emerges as an adult in the Spring.  They live all over North America, probably well into Canada.

Tachinid Flies look just like the Common Housefly:

http://www.wingwatchers.com/crawlies.html

Tiphiid Wasps -- Tiphia vernalis and T. popilliavora --  likewise spend most of their time on search and destroy missions for Junebugs. The University of Kentucky website posts results of a study that looked into whether spraying Sugar Water onto leaves would increase the populations of Beneficial Insects, especially on Tiphiid Wasps as a control of Junebugs:

http://www.uky.edu/Ag/ukturf/2002%20summaries/sugar%20sprays.pdf

They noted, 'Survival of Spring active Tiphia vernalis ...significantly increased when Wasps were provided with 10 percent sugar water....Large numbers of T. pygidialis visited turf sprayed with sugar water to feed ... Tiphia vernalis ... was never observed feeding on sugar-sprayed turf nor did such treatments affect its parasitism ... Large numbers of T. vernalis were observed feeding on nectar from a peony (Peonia lactiflora)

I am really out of space here, but I would just like to briefly add another point or two.

It is important to understand what triggered this population explosion -- if this is indeed what is going on -- with your local Grubs.  In the case of Japanese Beetles, at least, this problem generally seems to afflict large areas of newly disturbed soil.  There are natural pathogens and predators all over the place looking for juicy Grubs to eat.  You see the local Skunks making dinner reservations on your Lawn because you have the biggest, juiciest, most delicious Grubs in town.  If you are living in new construction, with a new  plot of recently disturbed soil, the natural controls were eliminated and have not recovered.  Fungus treatments wipe out ALL Fungi including the 'good' Fungi that restrict growth of ones we don't like as well as insect pests.  Something must have happened to decimate those natural controls in our soil.  You just want to identify it so that you don't do it again.... IF you did.

Sorry to be so long winded about this.  I know you had some other questions, but maybe you would like to re-pose them in light of all this new material.  I'll stop now.  More coffee, please.


---------- FOLLOW-UP ----------

QUESTION: Wow, great info! I am going to have to dig up those nematodes, but I live on a drumlin and my soil can get very dry periodically since we have soil clay and gravel down over 250+ feet.

I just wanted to fill you in on the lawn history, which is contrary to what would seem to be the case:

The house was built in 1973 out in the country. We have 16 acres, only 1.5 of which is lawn (and trials). One of my peeves is when people buy 10+ acres, tear down the brush, and then mow corner to corner and put up a bird feeder, but I digress. See: http://www.markwyman.com/photos/default.asp and the front door view to see the lawn about a month before grub evidence.

From what I understand, the lawn history was such:
Cow pasture in pre 1970
House built, soil only disturbed immediately around the house only.
Intermittently mowed between 1973 and 2001 (read a lot of weeds, little expanses of grass)
Mowed regularly, seeded, and organically fertilized thereafter.

It took a few years, but the grass started winning out up to now.

I think what I have done is taken a lawn hostile to normal grub attractiveness so there were few natural predators, and turned it into a buffet. I am seeing the results of the predator prey relationship before it settles out. I just need to get the predators out here that I like. I like skunks, but not when they roll up the lawn. Normally they dig small holes, not peel back the grass.

I think for repair I will order some topsoil, mix it with peat and fert and rake it over the existing clods. Then I will lay down some hay and seed.

BTW I have seen a few of those wasps around. Nice to know what they are!

Thanks again for your time.

-Mark


ANSWER: '...when people buy 10+ acres, tear down the brush, and then mow corner to corner and put up a bird feeder...'

A-MEN, my friend!

Tell me, what do you mean by 'organically fertilized' your new Lawn?

You sound like the perfect neighbor.  Stunning photos you've taken, I love the Northern Lights photos you took, impressive pics of the Moon.  Oh... forgot to check your Grass photo, sorry, I'll get to that later.

I really think the buffet atmosphere you describe would only erupt from removal of natural predators.  Next year will probably be much tamer.

Regarding your plan to order 'topsoil' I generally try to discourage people from paying top dollar for this kind of material.  There is not legal definition of 'topsoil' and it often comes loaded with Weed Seeds and is unlabelled as to content.  Best soil you can get is the stuff you make yourself and amend with Manure (you probably do not need any more Phosphorous if this used to be a Cow Pasture) or Humus.  I don't think you should add any more Fertilizer, either, given the Nature-friendly history of your Soil.  As long as you have oodles of Earthworms, I think any new Grass would be grateful to be able to call your humble and perfect abode Home.  Thanks for writing.



---------- FOLLOW-UP ----------

QUESTION: For organic fertilizer I use milorganite http://www.milorganite.com/home/ which is a byproduct of human manure ;-) It is not over-the-top, and it tends to stick around in the soil and not rinse away. It provides "just enough" and is what I use in the vegetable garden which also is a mild deterrent to animals, though it didn't help against rabbits this year.

I usually mix it into the soil in a freshly turned-over garden along with peat moss to counteract our PH 8.5+ soil.

p.s. Rabbits are wonderful weed eaters. I have watched them consistently avoid grass and eat dandelions and other weeds. The problem is they like my lettuce and other vegetables. One of these days I will finish fencing in the garden.

I don't know about "perfect neighbor" I used to have a 1KW audio amplifier and some pretty large speakers for a home theater, but recently downsized thanks to having a kid. One of the advantages to having some space is being able to keep the dust off of the rafters. ;-)

Back to the subject: It is possible the previous owners had treated the lawn, but based on what it looked like when we moved in, it is unlikely. I am still leaning towards the screwy weather of wet/dry/wet cycles. God knows we have plenty of birds, but they have so much to work with that grubs probably got looked over.

I am willing to be this year's starling migration will probably put a huge dent in the population. We literally have countless numbers pass through in the fall.

-Mark

Answer
Maybe I'm too worried about this sodic soil you are growing in.  The Government of New South Wales runs a website to help its farmers.  The NSW people point to several reasons that irrigating crops with water testing for a high pH can interfere with nutrients.

They write that 'alkaline water may contain high concentrations of bicarbonate (generally in water of pH 8 and above) and carbonates (generally pH 9 and above). High bicarbonate and carbonate levels in water can cause calcium to precipitate from the soil: this reduces the soil's exchangeable calcium content and increases soil sodicity. Magnesium can also be lost in this way. In extreme cases, the loss of soil calcium and magnesium will affect plant growth. Some trace elements, like copper and zinc, will also be less available to the plant in this situation.'

Here's the webpage:

http://www.agric.nsw.gov.au/reader/water-quality-supply/ac2-pH.htm

Starlings -- MASTER Grubs Controllers.  They will annihilate the population, if they come.  Great to hear from you.