The recent hot and humid weather created perfect conditions for turfgrass diseases at the Horticulture Research Station. Specifically, we had an outbreak of pythium on a sand-based putting green. Just before the pythium damage we experienced an outbreak of dollar spot. We had shut the irrigation off to create some stress on the creeping bentgrass, and it created the perfect conditions for the disease with the low temperatures at night not getting out of the 70's and high humidity levels. This turfgrass area will now be renovated at the field day since pythium has killed it.
Pyhtium and dollar spot disease damage on creeping bentgrass. The dollar spot damage happened first with the small spots and then the pythium killed the rest.
Pythium damage on crepeing bentgrass stops at the change from sand (dead turf) to soil based (healthy) rootzones.
Pythium has the darker color brown/grey turf, and the small spots are dollar spot damage.