Dr. Hurley is known as the bentgrassdoctor and has been breeding Improved bentgrasses since 1982 to Include the advanced generation varieties 007, 777 and 007XL.
These advanced generation bentgrasses have the greatest opportunity for success in cool season climates for grassing greens, tees and fairways.
Now designated as a class of "Super BentsTM" these varieties will produce a turf showing greater disease resistance / lower fungicide use, finer leaves, a denser turf that is more tolerant to close mowing.
Within the "Super BentTM" class are the varieties 007, 777, 007XL -- as well as MacKenzie, Flagstick and Tyee.
For "Super BentTM" information contact https://sroseed.com/super-bents
For "Super BentTM" variety qualities contact
https://www.sroseed.com/find-a-product/bentgrass
ph: 570-350-8906
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Recent research findings on Bacterial wilt in creeping bentgrass,
a colaboration with URI, NC State and Rutgers Universities.
Bacterial wilt has been a concern for golf courses with bentgrass greens located mostly in hot summer climates.
Causal agents identified for bacterial wilt include strains of Xanthomoas translucens and Acidovorax avenae.
Bent greens maintained at lower cutting heights (below .125 inch or 3.2 mm) during summer heat stress favor bacterial wilt. Symptons to include a general wilting appearance of leaves as the bacterial present in the xylem (water transport) clogs the flow of water through the plants. Leaves shrivel, turn brown and collapse in a few days.
Recent research findings indicate that high use of Primo growth regulator during the summer heat and or with use of a Amonium Sulphate Nitrogen source may encourage bacterial wilt in bentgrass greens.
You may consider use of another plant growth regulator (during the summer season) in place of Primo (Trinexapac-ethyl) i.e. Trimmit (Paclobutrazol) or Cutlass (Flurprimidol). Use of Trimmit or Cutlass on bentgrass greens during the summer months do not appear to be associated enhancing bacterial wilt activity.
Additionally, research findings indicate the use of the fungicide Daconil Action applied as a perventative treatment may reduce leaf etiolation (elongation) that some people may associate with symptoms of bacteria wilt. Leaf etiolation on turfgrasses has been referred as "mad tiller" or "crazy tiller" and may be observed during periods when bacterial wilt is active.
At present there is no recommended treatment for controlling bacterial wilt on bentgrass greens.
The best advice is to reduce stress on a bentgrass green growng in a hot climate or microclimate i.e. raise the mowing height during the summer (above .125 or 3.2 mm), add fans to improve air circulation over the surface of a green, remove trees to allow better air flow around a green site and to provide maximum sunlight (minimum of four to five hours of direct sunlight reaching the surface of a green each day).
Most importantly would be to regrass the surface of the greens with more heat tolerant and resistant varieties of bentgrass is advisable.
The A and G varieties have been shown to be more susceptible to bacteral wilt on bentgrass greens while the varieties 007 and Tyee have been shown to be more resistant to bacterial wilt.
Research reports showing varying levels of bentgrass susceptibility to Acidovorax avenae bacteria.
Paul Giordano NC State University in collaboration with Mathew Mitkowski at URI., 2013. Published in Plant Disease. 96:1736-1742.
Of twenty creeping bentgrass varieties included in testing, 007 and Tyee displayed less damage after inoculation with Acidovorax bacteria compared the A4 and G2 varieties.
007 bentgrass control, not inoculated with Acidovorax avenae, photo below.
007 bentgrass inoculated with Acidovorax avenae, photo below.
Tyee bentgrass control, not inoculated with Acidovorax avenae, photo below
Tyee bentgrass, inoculated with Acidovorax avenae, photo below.
Penn A4 bentgrass control, not inoculated with Acidovorax avenae, photo below.
Penn A4 bentgrass inoculated with Acidovorax avenae, photo below.
Penn G2 bentgrass control, not inoculated with Acidovorax avenae, photo below.
Penn G2 bentgrass inoculated with Acidovorax avenae, photo below.
Superintendents with bentgrass putting greens, mostly in transition climates, have reported significant turf damage and thinning during the summer stress periods.
G2 bentgrass greens at Quail Hollow GC in North Carolina had a history of suffering from significant summer turf damage and thinning.
Most reports of damaged bentgrass greens with bacterial wilt were on the varieties Penn A-1, Penn G-2, Penn A-4, and L-93.
Research at Rutgers University reported high soil temperature is the most critical factor in decline of bentgrass and other cool season grasses during the summer.
Multiple studies have shown that high soil temperatures, whether the air temperature is low or high, is detrimental to root growth. Research by Dr. Bingru Huang, Rutgers University, found a decrease in soil temperature from 95 degrees F to 90 degrees F at 0.125 to 0.157 inch mowing height maintained acceptable turf quality for L-93 and higher turf quality for Penncross over 21 days.
Significant increases in tiller density, clipping yield and root number were observed when soil temperatures were reduced from 95 to 85 degrees F.
Cooling the soil at night was more effective than daytime cooling in maintaining turf quality. At high soil temperatures plant respiration increases and uses up the energy reserves of the plant stored in the roots and crowns.
Young bentgrass greens may suffer more since they are more upright, have less leaf surface and less extensive crowns and stolons so less reserves.
Management Recommendations for Bentgrass Greens Growing in a Hot Climate.
Copyright 2013 R.H. Hurley, LLC. All rights reserved.
ph: 570-350-8906
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