| |
| Publication Type:
| Report |
|---|
| Content Type: | Abstract or Summary only |
|---|
| Author(s): | Doney, J. C. Jr.;
Vincelli, P. |
|---|
| Author Affiliation: | Department of Plant Pathology, University of Kentucky, Lexington, KY 40546-0091 |
|---|
| Title: | Control of Sclerotinia homeocarpa with reduced sensitivity to DMI fungicides on two greens, 1993 |
|---|
| Source: | Fungicide and Nematicide Tests. Vol. 49, 1994, p. 327. |
|---|
| Publishing Information: | St. Paul, MN: American Phytopathological Society |
|---|
| # of Pages: | 1 |
|---|
| Keywords: | TIC Keywords: Agrostis stolonifera; Dollar spot; Sclerotinia homoeocarpa; Disease control; Fungicide evaluation; Fungicides; DMI resistance
|
|---|
| Cultivar Names: | Penncross |
|---|
| Abstract/Contents: | "The trial was conducted on two Bentgrass greens (Meadow Brook and Tates Creek Golf Courses, in Lexington) with natural dollar spot infestations which were not controlled following a total of six applications of triadimefon to each green in 1992. Both sites have a history of dollar spot epidemics that were insensitive to triadimefon. Isolates of Sclerotinia homeocarpa from both greens had shown reduced sensitivity to DMI (demethylation inhibitor) fungicides in in vitro experiments (abstr. in Phytopathology in press). Both greens were on a granular turf management program prior to 1993 and each received a total of 6.5 lb N/1000 ft2 fertilization in 1992. On 26 Apr 93 the Tates Creek site was treated with Scott's TGR (paclobutrazole), and both greens were fertilized with 1 lb N/1000 ft2. The Meadow Brook site also received 1 lb N/1000 ft2 on 3 Jun. The greens in the experiment were maintained at a height of 3/16 inches and irrigated as necessary. Plots measuring 4 X 4 ft with 2 ft borders were established in RCB design (three replications) on both greens. Treatments applied were: four DMI fungicides, vorlan, thiram, Scott's Fluid Fungicide, and an unsprayed check. The treatments indicated in the table below were applied with a CO2-powered, hand held sprayer fitted with 8002 even flat fan nozzles delivering 3 gal/1000 ft2. Application dates for 2 week intervals were 27 Apr, 11 & 25 May, 8 & 22 Jun. Application dates for 4 week intervals were 27 Apr, 25 May, and 22 Jun. Dollar spot foci were counted in each plot every two weeks from 26 Mar to 17 Jul. The unseasonably cool weather during the experiment was not conducive to the development of dollar spot. No dollar spot activity was present at the time of the first application and this condition was typical for most of the season. Weather conditions were conducive to dollar spot only from the middle of May to the end of Jun. Due to differences in fertilization and disease pressure before and during the experiment at the two greens, data for each green were analyzed separately. No detectable differences (P=0.05) in the number of dollar spot foci were detected at the Tates Creek green. However there were very few dollar spot foci anywhere on the Tates Creek green during the experiment (range of 0 to 4 foci per plot). The relative lack of detectable differences in disease resulted from low disease pressure and not from reduced sensitivity to all fungicides tested, as evidenced by the extremely low disease severity in the untreated control. Significant differences (P=0.05) due to treatment were detected at the Meadow Brook green on two dates; 15 and 21 Jun. All fungicides tested at the Meadow Brook green failed to completely control disease. Dollar spot foci were present in all treatments on 21 Jun. Sentinel, Spotrete and Bayleton were not significantly different from the unsprayed control on 15 Jun. These data are consistent with the hypothesis that cross-resistance to some DMI fungicides has developed at Meadow Brook, since Sentinel, Banner and Rubigan had never been used previously on the site. Further research of these isolates under field conditions more conducive to disease development may yield more definitive information. |
|---|
| Language: | English |
|---|
| References: | 0 |
|---|
| Note: | This item is an abstract, with table, only! |
|---|
| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Doney, J. C. Jr., and P. Vincelli. 1994. Control of Sclerotinia homeocarpa with reduced sensitivity to DMI fungicides on two greens, 1993. Fungicide Nematicide Tests. 49:p. 327. |
| Fastlink to access this record outside TGIF: https://tic.msu.edu/tgif/flink?recno=34156 |
| If there are problems with this record, send us feedback about record 34156. |
| Choices for finding the above item: |
|---|
| 
MSU catalog number: SB 951.3 .F82 |
| Request through your local library's inter-library loan service (bring or send a copy of this TGIF record) |
