Department of Plant Pathology
DiMarco, J. N.; Majumdar, P. R.; Tredway, L. P.; Towers, G. W.; Weibel, E. N.; Clarke, B.
New Brunswick, NJ
Objective: "Fungicides were evaluated for their ability to control summer patch on Kentucky
bluegrass at the Rutgers Turf Research Farm in North Brunswick, NJ." Evaluation of Companion in
combination with chemical fungicides at reduced label rates.
Method: Turf was established Sep 1992 on a Norton loam soil with a pH of 6.4. The site was
mowed at 1.5 in., two times per week, and clippings were not collected. Turf was irrigated to prevent
drought stress. Fertilizer was applied as 15-0-0 on 8 Apr (0.21 lb N/1000 sq ft) and 22 Apr (0.56
lb N/1000 sq ft), and 16-4-8 on 13 Jul (1.0 lb N/1000 sq ft). Plots were 3 ft x 9 ft and were arranged
in a randomized complete block with four replications. Fungicides were applied in water equivalent to
4 gal per 1000 sq ft with a CO2 powered sprayer at 30 psi using TeeJet 8003E nozzles. Treatments (trt)
38 and 39 were watered into the thatch after each application with 1 gal water per plot. All treatments
were initiated on 29 May when the maximum soil temperature at a 2 inch depth reached or exceeded 65°F
for 5 consecutive days. Fungicides were reapplied at the appropriate intervals as indicated in the
table. Each plot was inoculated in three locations with 25 cc of oats infested with Magnaporthe poae,
isolate 73-15, on 28 May 1998. Percent turf area exhibiting foliar symptoms of summer patch was assessed
on 14 Aug, 31 Aug, and 11 Sep. Data were subjected to analysis of variance and means separation by
Waller-Duncan k-ratio t test (k=100) following arcsine transformation.
Results: "Summer patch was first observed on 5 Aug. Disease severity increased steadily through
11 Sep. On 14 Aug, all products except the 21.4 oz rate of QST 1713 W (trt 23), provided a significant
level of summer patch suppression. As the disease intensified on 31 Aug, most treatments containing CGA
279'202 50W (trt 6, 7, 9), Banner MAXX 1.24MC (trt 10-15), DAS 0025 (trt 18), Lynx 45W (trt 19),
Eagle 40W (trt 21), Companion (trt 24, 29, 30), and Heritage 50 WG (trt 29-37) continued to provide
good to excellent disease control. Excellent season-long control was only obtained, however, with
the 4 oz rate of Banner MAXX 1.24MC (trt 13), Banner MAXX 1.24MC + Primo L 1E (trt 15), S-7511 G
(trt 39), and Heritage 50WG alone (trt 35-37) and in combination with Companion (trt 29, 30), No
phytotoxicity was observed."
Companion® is a registered trademark of Growth Products, Ltd., Banner Max ® is a registered trademark of Syngenta Group Company, Eagle® is a registered trademark of Dow AgroSciences LLC, Heritage® is a registered trademark of Syngenta Group Company.