Lawn Question in Hennepin County

Question: Hello, I was wondering if there was someone I could ask about a new lawn problem I am having in south Minneapolis. I moved into my house last year in July and the lawn was green and maintenance free, but this spring a patch of our front yard appears to have died and is coming off in chunks from the surface. There have been some quarter diameter holes around this portion of the lawn, though I would have first guessed this was Japanese beetle larvae eating the grass roots. Any ideas on things I should try? I have also attached a picture if that is helpful.

responder: Paul W. U of M Extension Master Gardener Dakota County Replied May 11, 2023, 11:09 AM EDT
response: The small hole you see are from Voles, but I think there is more going on here than just vole damage. How to manage vole damage on lawns, trees and shrubs | UMN Extension.  When you say the lawn was "maintenance free", what did you mean by that?  Did you keep it mowed, mulched your clippings, fertilized, and watered?   Is it spreading into your neighbor's turf?  This could mean a fungal infection of some sort.   Please get back to me and we will go from there.

responder: The Question Asker Replied May 11, 2023, 1:26 PM EDT
response: Hey Paul, thanks for your reply. I'll answer the questions below. Last year the only maintenance I did was mowing the lawn. I did water it a couple times, but not regularly. I did not fertilize at all but I moved in there in July so I'm not sure if it was fertilized earlier.I have a sidewalk bisecting the yard, and the patch is only on one side of the sidewalk. The immediate neighbor next door has no issues with their lawn, but I believe they also have a service come and regularly fertilize. The neighbors on the other side appear to have a similar problem to mine, but it is likely 15ft away.If it does help - a neighbors' tree lost a significant branch at the very end of last fall which fell into this part of the yard (I actually found some pieces still in the yard after the thaw this year). The tree looked mostly healthy, but a large branch broke off during heavy rainfall. The tree was cut down and removed this winter. Again, not in our yard but immediately next to this problem patch in our neighbors yard.Thanks again,DerekOn Thu, May 11, 2023 at 10:09 AM Ask Extension <<personal data hidden>> wrote:

responder: Paul W. U of M Extension Master Gardener Dakota County Replied May 13, 2023, 7:00 AM EDT
response: I am thinking that the drought and lack of water did the turf in. When turf grass is not watered it does go "dormant" to an extent, but if it is sunny and hot,  the crown of the turf grass will die and the plant dies.  Your neighbor's tree probably shaded this part of the yard and when the limb came down, the growing environment changed from partial shade to full sun. That just made the problem worse.  You will need to do a renovation. The easiest way is to simply sod the area. Here is an (lengthy) article on renovation: Renovating a lawn for quality and sustainability | UMN Extension  Since the damage just happened this past fall/winter you might try just raking the area and then overseed with a sunny seed mixture. We are recommending fescue grass mixes. After you seed keep the area watered.  Once things are established you need to take care of the turf grass. Keep it mowed regularly and mulch your clippings, don't pick them up. Mulching does not build up thatch, but rather puts nutrients back into the soil as the clippings compost down. This practice is worth one fertilization a year.  Keep the turf watered. This doesn't mean watering every other day, just when the turf needs it.   Turf grasses need fertilization. You can do it yourself or hire a service. With good lawn practices, three times a year is enough: once in the spring, once in late summer, and once again in the fall.  Lawn care | UMN Extension  Hope this helps!!

responder: The Question Asker Replied May 15, 2023, 4:13 PM EDT
response: Hey just following up again. I did some further work on the turf this weekend raking the affected areas and pulling the dead turf back, and I found a significant number of grubs that look a lot like Japanese beetle grubs to me (see attached photo). It appears that there is a significant amount present under the dead layer of turf. Is there anything I should do now for larvae control? I have used nematodes at a different address before but have not yet here.Thanks!DerekOn Sat, May 13, 2023 at 6:00 AM Ask Extension <<personal data hidden>> wrote:

responder: Paul W. U of M Extension Master Gardener Dakota County Replied May 17, 2023, 6:36 AM EDT
response: I can't tell from the picture what kind of grub it is, but you need to take care of the grubs before you renovate. Now is the time to take action: As snow recedes, white grub damage is revealed | UMN Extension White grub control in lawns | UMN Extension