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| Web URL(s): | https://www.plantmanagementnetwork.org/pub/trial/fntests/reports/2000/55-510.pdf
Last checked: 05/03/2017
Requires: PDF Reader |
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| Publication Type:
| Report |
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| Author(s): | Wetzel, H. C. III;
Butler, E. L. |
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| Author Affiliation: | Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina |
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| Title: | Evaluation of fungicides and Urea for the control of bentgrass dead spot in an `L-93' putting green in Raleigh, NC, 1999 |
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| Section: | Turf grass reports
Other records with the "Turf grass reports" Section
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| Source: | Fungicide and Nematicide Tests. Vol. 55, 2000, p. 510. |
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| Publishing Information: | St. Paul, MN: American Phytopathological Society |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Urea; Disease severity; Quality; Agrostis stolonifera; Fall spot of bentgrass; Ophiosphaerella agrostis; Fungicide evaluation; Fungicides; Fungicide combinations; Disease control; Golf greens; Agrotis ipsilon; Pythium diseases; Plant recovery
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| Cultivar Names: | L-93 |
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| Abstract/Contents: | "A test was established on 14 Jul on the 5th green at the Raleigh Golf Association (RGA), 1527 Tryon Road, Raleigh, NC 27603. This putting green was constructed to USGA specifications of 80% sand: 20% peat and established to the creeping bentgrass variety 'L-93' in Aug 98. The soil pH was 5.8. Bentgrass dead spot (BDS) symptoms first became evident on 4 Jul and were diagnosed by the assistant golf course superintendent with a handlens noting the presence of abundant, black pseudothecia embedded within the turfgrass foliage and the lack of foliar mycelium in these dead spots in the early morning hours. Fungicides applied prior to establishing this test are as follows: 30 Jun Heritage 50WG at 0.4 oz, 5 Jul Daconil Zn 4.17F at 11 fl oz plus 0.125 lb nitrogen from 10-2-10, 6 Jul Chipco 26GT 2SC at 8 fl. oz, and 8 Jul Cavalier 50WSB at 4.0 oz. Thus, a true untreated control was not available for this study. All products applied by the superintendent's spray technician were applied on an oz per 1000 sq ft basis with a Hahn sprayer equipped with a Spray Hawk walk-behind spray boom to deliver 2.0 gal H₂O per 1000 sq ft. Putting green fertility program consited of supplying 0.75 lb nitrogen per 1000 sq ft per month (Apr through Sept) from Green Relief. Prior to visible BDS symptoms, daily mowing consisted of using a John Deere walk-behind greensmower at 0.150 in. After BDS Symptoms appeared, mowing height was increased to 0.165 in and frequency consisted of mowing every other day with lightweight walk-behind Toro Greensmaster 500 mowers. Plot size was 3 ft 4 in x 5 ft (16.65 sq ft) replicated four times in a randomized complete block design. Fungicides and urea were applied in 3.2 gal H₂0 per 1000 sq ft with a backpack CO₂-pressurized (36 psi) sprayer equppied with two flat-fan TeeJet 8010 nozzles on a 20 in spacing. Treatments were applied between 7:00 and 9:00AM, just after the turfgrass had been mowed, to allow for maximum fungicide/nitrogen absorption to the turfgrass canopy. Fungicide treatments were not watered-in following application. Black cutworm (Agrotis ipsilon) larvae were treated on 28 Jul with RegalFate 6.3G at 3.0 lb/1000 sq ft. Two black cutworm larvae per square foot were counted as the larvae came to the surface from the treatment. Preventive treatment of the entire study area of Pythium blight occurred on 5 Aug with Banol 6S at 2.0 fl. oz/1000 sq ft and 19 Aug with Subdue MAXX at 0.5 fl. oz/1000 sq ft. Pythium blight fungicides were applied with backpack CO₂-pressurized (36 psi) sprayer equipped with three TeeJet 8010 flat fan nozzles to deliver 2.0 gal H₂O/1000 sq ft. Distribution of BDS symptoms across the entire study area was quite uniform. All ratings occurred weekly the day prior to treatment applications. Initially, BDS infection centers per square foot were counted in three fixed locations in the central portion of each plot. Noticeable recovery was observed in mid-Aug for certain treatments, so the total numbers of BDS infection centers were also assessed per plot. Turfgrass quality was assessed on a 0 to 10 scale, with 0 being comletely brown or dead turf; 8 being minimal acceptable quality for golf course putting green turf; and 10 being optimum turf density and greenness. Data were analyzed using the SAS PROC GLM procedure and significantly different treatment means were separated using Fisher's protected LSD procedures at the P=0.05 level. Curative control of bentgrass dead spot (BDS) was a slow process with any of the fungicides or fungicide/urea combinations tested. Significant recovery from BDS initial infections was not noted until approximately one month after treatments were initiated. This could be due to the nature of this disease or in combination with the extremely hot and dry environmental conditions experienced in Raleigh. Daconil Ultrex, Cleary's 3336, reduced rate tank mix combinations of Daconil Ultrex with either Chipco 26GT or Cleary's 3336, ConSyst, Spectro, and Fore Rainsheild NT in combination with 0.125 lb water-soluble nitrogen from urea provided the best control of BDS when compared with urea alone and the untreated control. Chipco 26GT, BAS 500 and 505 provided better curative control than Heritage and Compass. Turfgrass quality was influenced by recovery of BDS and those treatments that were tank-mixed with urea exhibited better turfgrass color. The Green Relief nitrogen fertility program did not supply adequate amounts of nitrogen for this newly established USGA specification putting green which most likely influenced the overall recovery of the turfgrass from BDS. Symptoms of BDS were greatly diminished after Hurricane Floyd 14 Sep and only reoccurred on two greens mid-Oct but not to the extent as was observed earlier in the summer. This was the first growing season in which BDS was diagnosed in North Carolina." |
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| Language: | English |
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| References: | 0 |
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| Note: | Tables |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Wetzel, H. C. III, and E. L. Butler. 2000. Evaluation of fungicides and Urea for the control of bentgrass dead spot in an `L-93' putting green in Raleigh, NC, 1999. Fungicide Nematicide Tests. 55:p. 510. |
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https://www.plantmanagementnetwork.org/pub/trial/fntests/reports/2000/55-510.pdf
Last checked: 05/03/2017
Requires: PDF Reader |
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MSU catalog number: SB 951.3 .F82 |
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