Evaluation of Fungicides for Control of Dollar Spot in Penncross Creeping Bentgrass - 2000
Mark L. Gleason
Trials were conducted at the Turfgrass Research Area of Iowa State University's Horticulture Research Farm, Gilbert, IA. Fungicides were applied to Penncross creeping bentgrass maintained at 5/32-inch cutting height, using a modified bicycle sprayer at 30 psi and a dilution rate of 5 gal/1000 ft2. The experimental design was a randomized complete block with four replications. All plots measured 4 ft x 5 ft.
After inoculation of the entire plot with pathogen-infested rye grain on June 8, spray applications began on June 14. Subsequent applications were made at specified intervals on June 29 and July 12.
Weather during June and July was slightly below normal in temperature and rainfall. Dollar spot symptoms appeared in the plot within 2 weeks after the first spray treatment. Disease development was light on both rating dates (June 29 and July 24). Most, but not all, treatments exhibited significantly less disease than the untreated control on July 24.
DOLLAR SPOT TRIAL — 2000
ISU Horticulture Farm (Penncross creeping bentgrass)
Plot size: 20 ft2 (4 ft x 5 ft); 4 plots per treatment
Dollar Dollar
spot sev spot sev
Trt # Company Product Rate/1,000 ft2 Interval (%) (%)
(days) 6/29/00 7/24/00
1 Check ---------- ------------- --------- 2.75 3.50
2 Bayer Lynx 45WP 0.56 oz 14 0.08 0.00
3 Bayer Lynx 45WP 0.28 oz 14 0.53 0.00
+ Daconil Ultrex 82.5WG 1.82 oz
4 Rohm and Haas Eagle 40WSP 0.6 oz 14 0.93 0.00
5 Rohm and Haas Eagle 40WSP 1.2 oz 28 0.93 0.10
6 Rohm and Haas Fore Rainshield 8 oz 14 1.55 1.88
7 Rohm and Haas Fore Rainshield 6 oz 14 2.50 0.00
8 Rohm and Haas RH-0611 (Manhandle) 10 oz 14 0.13 0.00
9 Novartis Banner MAXX 2.0 oz 14 0.00 0.00
10 Bayer Bayleton 25WP 0.5 oz 14 0.80 0.03
11 Aventis Daconil Ultrex 82.5WG 3.2 oz 14 3.75 2.50
12 Tomen Agro TM-41702 40WP 0.10 oz 14 3.53 1.53
13 Tomen Agro TM-41702 40WP 0.25 oz 14 1.80 0.15
14 Tomen Agro TM-41702 40WP 0.50 oz 14 1.65 0.03
15 Tomen Agro TM-41702 40WP 0.70 oz 14 0.90 0.03
16 Tomen Agro Daconil Ultrex 82.5WG 1.8 oz 14 1.30 3.63
17 Tomen Agro Daconil Ultrex 82.5 WDG 1.8 oz 14 6.78 4.28
+ Heritage 50WG 0.2 oz
18 Tomen Agro TM-41702 40WP 0.25 oz 14 0.40 0.00
+ Heritage 50WG 0.2 oz
19 Tomen Agro TM-41702 40WP 0.5 oz 14 0.20 0.00
20 Tomen Agro TM-430 50SC 0.267 gal/A 14 3.75 4.75
21 Tomen Agro TM-430 50SC 0.535 gal/A 14 4.20 3.13
22 Tomen Agro TM-430 50SC 0.962 gal/A 14 1.63 2.50
23 Tomen Agro Heritage 50WG 0.3 oz 14 2.00 1.78
24 Tomen Agro Daconil Ultrex 82.5WDG 3.8 oz 14 2.28 0.80
LSD (0.05) 2.71 2.83