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…]

Bacterial Decline of Creeping Bentgrass

Several golf courses in the tri-state area have reported symptoms of etiolation and decline of creeping bentgrass putting greens.   In some cases, the etiolation has occurred in isolated areas and then disappeared, but in other situations etiolation has progressed into a gradual decline of affected turf.  Patches can range from 1 to several inches in diameter and may coalesce into large areas of blighted turf.   Repeated isolations has yielded a number of bacterial species including Acidovorax and infected turf has often exhibited pronounced bacterial streaming from cut leaf tissue.  Annual bluegrass on these greens has been unaffected by this problem.

Although little is known about the etiology and control of etiolation and bacterial decline of turf, it appears to be stress related with the recent heat wave acerbating the problem.   Anecdotal evidence from superintendents who have combated etiolation and decline suggests that recovery is encouraged by: (1) raising the height of cut, switching from heavy to light weight mowers, reducing rolling (not mowing) frequency, and using solid rollers on mowers, (2) hand syringing to avoid soil moisture extremes (particularly drought stress), (3) stopping the use of vegetative plant growth regulators (such as Primo) or reducing the rate and/or increasing the interval between applications, (4)  avoiding the use of ammoniacal fertilizers (e.g., ammonium sulfate) in favor of nitrate-based sources during symptom expression, (5) avoiding heavy topdressing applications during hot weather (> 90°F) and dispersing bunker sand on greens each day (e.g., with a back pack blower prior to mowing), (6) delaying aerification, spiking, or other cultivation practices until the problem subsides, (7) reducing shade, and (8) improving air circulation around greens to reduce the leaf wetness period.

Currently, there do not appear to be any really effective chemical treatments for the control of etiolation and bacterial decline on bentgrass.  Junction and other copper-based fungicides have provided limited control and can burn turf during hot weather.  In some cases, Daconil Action has increased the quality of affected turf, but has not provided outstanding control of bacterial decline.  Antibiotics (e.g., Mycoshield) have given little suppression of outbreaks during hot weather, can be very phytotoxic, and are not labeled for use on turf.  ZeroTol (a surface disinfestant) has appeared to reduce symptom severity on some courses when applied every 2 to 4 days, but has not controlled bacterial infections.  Until more research is conducted on this emerging problem, the best course of action is to reduce plant stress and avoid practices that cause excessive wounding of turf, particularly during periods of environmental stress.

Disease Activity on Research Plots

Anthracnose disease has become very aggressive during the last week on our Poa annua research plots in North Brunswick NJ (see image below).

[Read more…]

Anthracnose Basal Rot Is Active in NJ

 

Anthracnose (basal rot) symptoms have been developing on our research plots for a couple weeks now (see image from 13 June above). [Read more…]

Red Thread Sightings

Red Thread in North Brunswick June 1

I have observed a fair amount of red thread disease this spring. This disease has been most active on perennial ryegrass (see attached image). It has also been seen this spring on tall fescue and fine fescues but to a lesser extent than perennial ryegrass.

Red thread disease tends to be more aggressive in full sun than shade and it often appears where soil fertility and organic matter are low. The recent warm weather will probably make this disease less active but it could resume if cooler wet weather returns. See Fact Sheet FS798 for more details.

Looking forward, turf disease activity is shifting towards brown patch disease as the weather warms. So you could see an influx of inquiries about brown patch if you haven’t already; there was a large increase in this disease at the research farm this weekend. N fertilizer can stimulate brown patch disease, so applicators needs to use moderate to low rates and/or slow N fertilizer.