Grass

Asked June 29, 2016, 12:26 PM EDT

My grass generally has been doing well the past few years. I had a soil sample taken and I use a good blend of fertilizer. I also apply Milorganite a few times a year. I noticed last week some weeds throughout the yard. I sprayed weed/feed with a hose end sprayer. Could that be causing the browning? And if so is the grass dead or can I revive it back to life my watering?

Minnesota turfgrass problem horticulture lawn

2 Responses

There are a few possibilities. Your guess about the weed and feed may be correct. If you apply Milorganite, which is a fertilizer, several times a year AND spray with a weed and feed during hot weather, you could be potentially burning your grass. If that's the case, keep watering and your lawn should snap back.

But first check for root-feeding insects, such as June beetles or Japanese beetle grubs:
http://www.extension.umn.edu/garden/insects/find/lawn-and-turf-insects/root-feeding/

If one of these is the problem, you'll have to treat for it.

One final comment: the rectangular pattern of damage I'm seeing is consistent with something like a fertilizer spreader, although you said you used a hose sprayer. Perhaps the milorganite was put down with a spreader?

Another possibility is an uncommon insect called cottony grass scale:
http://blog-yard-garden-news.extension.umn.edu/2009/12/cottony-grass-scale-year-later.html

The pattern I'm seeing in the lawn could be caused by a mower tracking through the infected blades.

As far as I know there is no treatment for CGS, but it seems to thrive in heavily fertilized lawns (which is what you have). Try reducing your fertilizer application to two or, at most, three times per year. Remember that weed-and-feed mixes include a fertilizer.