The Return of Southern Blight

I am of course stating the obvious that the summer season is a taxing one on the turf here at Granite Bay. Any golf course with primarily cool season grasses will inevitably have some issues July and August. Granite Bay is no exception. Of course our main issue through July so far has been putting surface decline and the resulting performance or putting inconsistencies as we reacted to the decline. When the greens “go south” every other issue seems to magnify. One of those issues that we are battling is a pretty decent outbreak of a disease called Southern Blight (sclerotium rolfsii).

Southern Blight infestations have been steadily increasing here at Granite Bay for the past six to seven years. We typically see the disease in higher mowed turf or “rough” around greens, tees and fairways. It is a nasty looking disease pattern which has really taken a toll this season at the same time, to add insult to injury, the putting surfaces were in decline.

We treat areas that have a history of the disease preventively but we had a stretch of perfect conditions which facilitated infection in new areas. We treated again once new infection became evident and the disease spread has stopped.

Southern blight has small fruiting bodies that over winter in the thatch and explodes when environmental conditions become right. I think I have mentioned that thatch is not only an issue in our putting surfaces but also it is an issue through out the turf here at Granite Bay. There is no guarantee that going aggressively after the thatch in rough and green surrounds would eliminate the threat or infection of Summer Patch. It does however make sense that by removing the excessive organic matter that the pathogen over winters in and creating a healthier environment for the plant, that disease pressure would be mitigated. Bottom line is excessive thatch is the common to most of the problems we have with our turf here at Granite Bay and we must get more aggressive at removing and controlling it.

"Sclerotina" or fruiting bodies of Southern Blight in the thatch layer

Souther Blight behind #2 green