what causes large circles of dead grass
The patch diseases: These include the delightfully named necrotic ring spot, yellow patch, summer patch and fusarium blight. All display a 'frog's eye' appearance: rings of dead grass with an 'eye' of healthy turf in the middle of each ring. Biggest causes: compacted soil and thatch.
Necrotic Ring Spot. Necrotic Ring Spot is another serious lawn disease that can destroy a lawn very suddenly. Its patches or rings of dead grass are brought on by dry, followed by wet, weather. Lawns 2 to 8 years old are favorite victims.
Other Causes Of Bare Lawn Patches. 1  Lawn Scalping is often a cause for dead patches in the lawn, it occurs when too much leaf material was removed during mowing, usually due to infrequent lawn mowing which raises the crowns of the lawn, and once the crowns are damaged or removed, the affected lawn area may die off.