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2010 Wrap Up from the West - Top 10 Diseases


Happy New Year to Everyone!!!
2010 was a mixed year, many California superintendents said that it was one of the best years for growing grass (we had some good rainfall this winter and a mild start to the summer), while I heard from a number of superintendents in the Pacific Northwest that the year was somewhere between sh*tty and really sh*tty because of the hard freezes that came in late 2009 and put them behind the 8-Ball from the start of 2010. In any case, last year was really hard financially on our industry and I really hope that 2011 brings us some better fortunes!

Just a quick round up of 2010 based on what we saw in the diagnostic lab here at UC Riverside. It was a busy year here in the lab with over 90% of our samples coming from California, with the rest coming in from our neighbors in Washington, Oregon, Nevada and Arizona.

We received 310 packages this year with a total of 536 samples (plugs). Disease activity in the west was fairly constant with the majority of our samples coming in July and October, reflecting increased disease pressure in the early summer and then an odd spike of activity in the fall.


No surprises as far as what turf species we encountered the most....



Poa dominated the samples sent into the lab with 69% of our samples being annual bluegrass and almost all of these being from putting greens. Bermudagrass and perennial ryegrass came in 11 and 10% of the time, almost all from fairways and roughs. Surprisingly, it was a good year for creeping bentgrass with only 5% of our samples coming from bentgrass greens.

Pathogens were present in the samples about 81% of the time, and the diseases we saw reflected the high prevalence of annual bluegrass samples we received.

Leading the pack was anthracnose, which was diagnosed in 14% of 536 samples. This continues to be the number one problem for golf courses in the west on annual bluegrass.

Coming in at #2, algae was present in 6% of our samples; although algae is often not a "disease" per se, its presence often indicates poor growing conditions on putting greens, and it can slow down turf recovery and cause some significant yellowing of the turf.

Rapid blight was our #3 disease of the year. Although the rain we had early in the year seemed to slow down rapid blight development, it seemed that prolonged cloudy, mild conditions in the early summer and then again in the fall promoted the development of this disease on annual bluegrass putting greens.

Bipolaris leaf spot (#4) was commonly found as a disease on drought stressed turf, mainly from perennial ryegrass or other cool season species in fairways and roughs.

Summer Patch came in at #5, again affecting primarily annual bluegrass putting grens; one observation we made from this year was that summer fungicide programs that focused on foliar applications for anthracnose control and didn't use QoI or thiophanate-methyl applications monthly tended to get this disease. Just a reminder that we need to control both of these diseases at the same time, which may require different fungicide strategies.

Large patch on kikuyugrass and bermudagrass was our #6 problem. Not surprising with all of the rain we got this last winter.

At #7 was Pythium Root Rot. This is still a little bit of a controversy - many of the locations where we diagnosed this were annual bluegrass putting greens also affected by freeze damage or had cold wet conditions. So what came first? Was the Pythium a weak pathogen attacking weak plants or did Pythium root rot make the plants weak?

Fairy ring came in at #8 on just about all turf types, with many of the diagnoses coming in the early spring. Lane's work at NCSU on preventive applications with DMIs when soil temps are 55 makes a lot of sense when controlling this disease.

Although foliar Pythium was our #9 disease, many of these diagnoses also came during periods of extended cold or warm wet weather and not necessarily during those hot hot 100 during the day, 70 at night type of situations where you'd expect Pythium to fire. We even picked up Pythium on bermudagrass this fall, how weird is that? My take away lesson from 2010 regarding Pythium was that as long as it's wet, you can get foliar Pythium.

Finally at #10 was brown ring patch. Since we saw it only 20 or so times this year on annual bluegrass putting greens, I hope that means that most superintendents are recognizing it early and controlling it fairly easily with fungicides and increasing nitrogen fertility.

OK - I hope this quick round up of 2010 diseases helps for 2011 disease management planning in the West. Until then, keep an eye out for those diseases!

Signing off from the Left Coast....

One response to “2010 Wrap Up from the West - Top 10 Diseases”

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