Weather Ideal for Pythium and Brown Patch

The weather this summer has been very conducive for brown patch and Pythium blight diseases. I have received number requests this summer to address turf problems related to one or both of these diseases in lawns, sports fields, sod and now my own plots.

Suspected initial outbreak of Pythium on velvet bentgrass maintained at a 0.110-inch height that occurred over the weekend (August 7) in a cultivation trial at Hort Farm No. 2 in North Brunswick NJ.

Suspected initial outbreak of Pythium on velvet bentgrass maintained at a 0.110-inch height that occurred over the weekend (August 7) in a cultivation trial at Hort Farm No. 2 in North Brunswick NJ.

The weather forecast for the rest of this week indicates [Read more…]

Killing Freezes… Finally

Many people are pleased that typical winter temperatures have taken so long to show up. Below are some interesting observations from early- to mid-winter in New Brunswick.

Relatively warm soil temperatures (as high as mid-60s °F) stimulated growth late into December.

Dandelion bloom on 15 December 2015 in New Brunswick.

Dandelion bloom on 15 December 2015 in New Brunswick.

Had to remove cover (folded up in behind Kyle Genova) from our K-Microdochium Patch trial so that it could be mowed on 16 December 2016!

Removed the permeable growth cover (folded up behind Kyle Genova) from our K-Microdochium Patch trial to mow it on 16 December 2016!

 

 

 

 

 

 

 

Winter flush of seedheads on annual bluegrass

Annual bluegrass can go to seed about anytime of the year but this is a first for me — lots of annual bluegrass seedheads on 28 December 2015 in New Brunswick.

 

 

 

 

 

Kyle Genova pulled back permeable turf cover to inspect annual bluegrass growth and progress of the Microdochium Patch inoculation on 28 December 2015. Turf is still growing and disease is expanding.

Kyle Genova pulled back the permeable turf cover from the K-Microdochium Patch trial on 28 December 2015. The annual bluegrass was still growing enough to schedule another mowing. And the progress of the Microdochium Patch inoculation was expanding (good for the research but ugly!). No disease response to potassium at this point.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Odd to find weed species that are normally gone by this time of the year. Killing frosts/freezes are finally here and frost sensitive plants should be damaged and won’t persist much longer. Cool-season turfgrasses will transition into dormancy if freezing temperatures linger for a while. But it won’t be too long (66 days until spring, 20 March) before annuals like prostrate knotweed will germinate and start to emerge from bare soil areas.

Freeze Injury on Weeds

Don’t recall prostrate knotweed (annual) persisting into January. But freezing temperatures have finally killed the knotweed. Also note that the leaves of broadleaf plantain (perennial) have just now been frost damaged.

 

Right On Cue: Dollar Spot Disease

Exactly like Dr. Bruce Clarke teaches, Memorial Day arrives and so does dollar spot disease.

Symptoms appear as round, brown to straw-colored spots approximately the size of a silver dollar. On short cut turf, the spots with advanced damage can become somewhat sunken. At taller cutting heights (greater than 1 inch), the damaged spots are larger and more diffuse.

Highly susceptible grasses will be the first to exhibit symptoms including annual bluegrass, creeping bentgrass (depending on cultivar), and perennial ryegrass. Tall fescue and most Kentucky bluegrasses will be more tolerant of this disease.

Cultural techniques that can suppress dollar spot disease include disruption of dew and guttation water in the morning and increasing N fertility (if it is low). Mowing early in the morning (disruption of dew) should also be helpful.

Creeping bentgrass entries in Dr. Stacy Bonos' evaluation trials that are highly susceptible to dollar spot disease appear in the image foreground.

Creeping bentgrass entries in one of Dr. Stacy Bonos’ evaluation trials that are highly susceptible to dollar spot disease (image foreground).

Brown Ring Patch Spotted in New Jersey

Brown Ring Patch (aka Waitea patch) is starting to show up on golf course putting greens at this time.  This disease is caused by the fungus Rhizoctonia circinata var circinata and typically develops during warm weather from April through June.  Symptoms start as small yellow rings (0.25-2 inches wide) with green grass in the center and can ultimately reach a foot or more in diameter. The yellow rings can turn an orange or brown color as the disease progresses.  Although the disease rarely kills turf, affected areas are extremely slow to heal.  For best results, apply Medallion, polyoxin-D (e.g., Affirm or Endorse), ProStar, one of the QoI fungicides (e.g., Heritage or Insignia), Trinity, Triton Flo, or Torque now and repeat in two to three weeks to limit disease development later this spring.   Unlike yellow patch, the brown ring patch fungus can degrade the thatch in infected areas so several fungicide applications are typically required to prevent significant damage.  Seedhead suppressants (e.g., Proxy + Primo) may enhance disease severity.  Therefore, be sure to initiate a preventive brown ring spot fungicide program in areas where this disease has been troublesome and seedhead suppressants have been applied.  For more information on brown ring patch, click here.

Brown ring patch on a golf green (Photo courtesy of S. McDonald)

Brown ring patch on a golf green (Photo courtesy of S. McDonald)

 

Leaf Spot and Melting-Out is Active

Leaf Spot of Kentucky bluegrass.

Leaf Spot of Kentucky bluegrass.

The leaf spot phase of this disease, caused by the fungus Drechslera poae, is apparent on susceptible Kentucky bluegrass turf at this time.

Melting-Out of Kentucky bluegrass.  A resistant cultivar (left) compared to a susceptible cultivar (right).

Melting-Out of Kentucky bluegrass. A resistant cultivar (left) compared to a susceptible cultivar (right).

To prevent severe damage from the melting-out stage of this disease during the next six weeks, avoid heavy applications of nitrogen in the spring (not more than 0.5 lb N / 1,000 sq. ft. / application of quick-release, water soluble formulations such as urea or ammonium nitrate), maintain the cutting height at or above 2 to 2-1/2 inches, remove excess thatch, and apply Armada, Compass, Disarm, Headway, Heritage, Insignia, mancozeb, Medallion, Tartan, or Velista now, per manufacturer’s recommendations.  Avoid the use of certain acropetal penetrant fungicides (e.g., benzimidazoles) this spring in areas with a history of leaf spot and melting-out, since these fungicides may intensify symptom expression.

Tough Year for Summer Patch Disease

I have seen as much disease damage on turf this summer as any year since I began living and working in New Jersey (1991).

summer patch disease on hard fescue

Severe summer patch disease on hard fesuce at Hort Farm No. 2 in July 2013.

The hot humid weather has been ideal for summer patch and brown patch diseases.

Summer patch disease is caused by a root infecting pathogen, Magnaporthe poae. Wet weather combined with high air (soil) temperatures are thought to be very conducive to the development of summer patch disease.

I have observed more damage from summer patch disease on hard fescue turf than Kentucky bluegrass this year. This is likely due to the fact that more people are growing varieties of Kentucky bluegrass with better tolerance to this disease than was the case 20 or more years ago.

The Rutgers turfgrass breeding program is working on improving the tolerance of hard fescue to summer patch disease.

There are some cultural techniques that [Read more…]

Anthracnose Active on Annual Bluegrass

Anthracnose disease was active as early as April 16 this year and has intensified in recent weeks on our low N fertilization plots.

Active anthracnose disease on annual bluegrass (Poa annua) plots in North Brunswick NJ, 16 April 2013.

One of our experiments has the objective of determining whether anthracnose can be managed with curative sprays if [Read more…]

Dollar Spot Activity Flares Overnight

The high humidity of last night (28-29 May) caused dollar spot disease to escalate. Until last night, symptoms on unprotected susceptible turf were minor.

The cottony fungal growth (mycelia) of dollar spot, which is easily seen at early morning hours during wet humid weather.

Susceptible grasses grown under low N fertility will typically have [Read more…]

Red Thread Disease is Active

Red thread disease on low maintenance turf.

Several weeks ago the cool wet weather brought on some red thread disease activity that has increased over the past 4 to 5 days. Turfs under low maintenance, particularly low nitrogen fertility, have been the areas with [Read more…]

Gray Leaf Spot Disease

Perennial ryegrass leaf blade damaged by gray leaf spot.

Many are planting new turf areas or re-seeding damaged areas using perennial ryegrass. Perennial ryegrass has the advantage of a fast establishment rate; a full turf cover can develop within 4 weeks. [Read more…]