Thanks for the response. I am not so sure they are Cicada Killer wasps. I looked at pictures of the Western variety. My wasps are smaller (about 1" long), and have more yellow than black. Also, a 'season' is mentioned that is from mid July to early August. These wasps have been around for 3 - 4 months. Lastly, there are photos of burrows showing a U-shaped trench with piles of dirt around it. I have many, many small mounds under the grass typically around 1" diameter. These don't seem typical of what I have read on the web about their egg burrows. Supposedly Cicada Killers like dry, sparsely vegetated areas to nest. These small mounds are deep under the grass. I have not seen any wasps carrying prey back to their nests, either. Are Cicada Killers the only explanation? What about another wasp variety eating grubs of some sort in the lawn?

antzy - You'll hear a lot here about avoidance of chemicals and not harming beneficial insects and the like. And believe me, all of it is good advice; after all, why kill an insect or worm if it is helping to aerate (and eventually fertilize) your lawn? However, I, for one, have suffered ant infestations that have so over-cultivated beneath the lawn that two areas dried out and died - because I was trying to leave them there after hearing they were good for the lawn (incidentally, I DO leave them in my front lawn, because they aren't creating mounds there and they aren't causing the lawn to die). Chemical control was a Godsend. Additionally, I nearly lost my front lawn to grubs (and the moles that followed) one year. Castor oil (nontoxic) successfully chased away the moles, but chemicals knocked out the grubs and saved the lawn. I now do alternating preventative treatments (Mach2 one year - Spectracide halofenozide product; Merit the next - Bayer imidacloprid product) - less toxic chemicals that replaced the more harmful "rescue" treatments necessitated by a previous avoidance of chemicals. I'm a busy man, but my lawn is a bit of a hobby and I've researched a lot of stuff, from toxicity to effectiveness. Ultimately, I've had a little experience, and continue to gain more. First, Rhizo's entirely right - Sevin's murder on earthworms. It can be a grub "rescue" treatment (admittedly, it's what I used to rescue my lawn), if necessary, but acc. to pros I've read from, Dylox (Bayer brand 24 hr. grub killer) is stronger (on grubs), breaks down more quickly in the soil, and won't cause AS MUCH harm to earthworms (though it certainly harms them). If you've determined you need some kind of control for pests, I would recommend you read the extoxnet and EPA info on the pesticides you're looking into, to see if they're good for your application. Additionally, lurk a bit on www.lawnsite.com, where professional lawn care people post regarding their experiences with different products (in the pesticide application section). For what it's worth, I've had great success with Triazicide - both granular and liquid (granules last longer) on killing ants in the lawn. Its active ingredient, lambda-cyhalothrin, is a synthetic pyrethroid - the family of chemicals used for interior insect killing in homes and restaurants. It lasts long because it bonds to the soil; however, while it's labeled for grub killing, many say it's bonding quality lessens the effectiveness (because doesn't get deep enough in the ground). As illustrated by synthetic pyrethroids' widespread approval for interior applications, it poses little if any threat to mammals when used according to directions and allowed to dry before reentry. Re earthworms, I have TONS of them after treating with Triazicide. I'm sure it's not good for them, but it hasn't changed their population noticeably. For grubs, halofenozide (Mach2 - the active ingredient in Spectracide Grub Stop) causes grubs to molt early, which in turn causes them to stop feeding and die. Imidacloprid (Merit - active ingredient in Bayer Season Long Grub Control and the new Scotts GrubEx) is brought into the roots of the lawn (systemic) and when young grubs bite, it kills them. Both are very light toxicity to mammals, but because they are so mild, their application must be timed with the grub (several beetle species, most common Japanese and June beetles) life cycle. Pros suggest you put them down in early July so that the young grubs get them right after their eggs hatch. Run a google search to learn about the grub cycle. Merit and Mach2 have virtually no effect on earthworms. If you have let the grubs mature come fall (or if your initial treatment fails), Bayer Dylox is the product to "zap" them. It uses Trichlorfon, an organophosphate insecticide, which is much more toxic to mammals so reentry rules must be observed carefully. Some suggest beneficial nematodes for grubs (and even ants, for that matter). But I've heard from many (including pros) that they are very inconsistent, die or burrow too deeply in dry weather, and are very expensive. I'm not going to use them. FINALLY, there is one product out that combines pyrethroids with Merit - Bayer's total lawn insect killer. It combines Cyfluthrin (a pyrethroid) with Merit, to get both contact killing of insects and systemic killing of pests that feed on grass roots. I may try this next season to see if it simplifies things. I share your concerns and wish you all the best.

Imp, For some reason, my DH is also a bee/wasp/yellow jacket magnet every time he walks out the door, but especially when he is mowing. Normally, it is the male cicadakillers who are aggressive and sting. (Hmmm, not surprising, is it?) It is sort of 'shocking' to watch one insect attack and subdue another. I sometimes see the same kind of battle between praying mantids and other insects. We also watch the argiope spiders (we have very, very many and some have had their webs in the same spots for months now) catch their prey in their webs quite often and it is very entertaining, especially when they are dealing with big old grasshoppers. With all the cicadas we have here in our rural area, it would take a billion cicadakillers to subdue them all, but I suppose the cicadakillers we have do help control them somewhat. I am sorry they're damaging your hostas. If I had hostas and they were tunneling around them, I am sure I'd be just as irritated as you are. The area in our landscape that the frequent the most has perennial Four O'Clocks which have tuberous roots that can get as large as a football, so the tunneling from the cicadakillers doesn't harm them. I used to have hostas in that spot, but then discovered that in our area the word 'hosta' is another word for 'deer chow'. To keep the cicada killers from digging, you'd have to put down something relatively solid like cardboard or cloth or plastic that they can't tunnel through. They love mulched areas because the mulch keeps the ground softer for them and makes it easier to tunnel in it. I have heard of folks mulching with gravel or some other form of decorative stone to deter them but haven't tried it myself and can't say I'm sure it would be a good solution here since rocks absorb heat and we have too much heat as it is. I suspect your hostas wouldn't appreciate heat collected/reflected from a layer of rock mulch. I don't even know of a natural predator that preys upon cicada killers, although there must be one of some kind. Dawn

A forest will choke out a thicket, I often recomend that fruit and nut trees be planted on purpose, so that we lock up carbon and produce food for ourselves, and chocke out the brush plants that are unpleasent to walk through. When you go on a hike along a tail it seems that you are always either bordered by clearing/lawn or by a thicket, but once you break through that thicket you can useually travle quite quickly and easily and have plenty of space to move about. The main reasonfor removing trees and brush historicly wasn't to make things more pleasent, it was to open up land for agricultural use. with a field we can grow staple cerial grains, or legumes, or use it as pasture for animals, while some trees may provide seasonal food for some critters it takes alot of work to survive off of them year round (and trust me when I say thing, willow does not taste that good) . Our modenr day lawns were not contrived from thin air, you need to look at were they came from to understand how they fit in. Lawns are popular mainly in the south (sure, lots of people like them, but in the south they are sick for them) the south had a large portion of its caucasian inhabitants come from scotland (the southern drawl is very closely related to the scots accent) in schotland they have huge green field that are kept down to a few inches all summer long, this is because there is alot of rain and people raise sheep. Now, in the south there isn't as much water in the summer, and there aren't as many sheep, but people still liked the look of home so a lawn with mowers and irrigation is what they came up with.