Fungicide Programs for Cool- and Warm-Season Landscapes Lane Tredway Associate Professor and Extension Specialist Department of Plant Pathology North Carolina State University 1
Each Turf Species Has Unique Problems Tall Fescue brown patch, gray leaf spot, Pythium blight Kentucky bluegrass dollar spot, summer patch, Pythium blight, rust, powdery mildew 2
Each Turf Species Has Unique Problems Centipedegrass large patch Bermudagrass spring dead spot, dollar spot Zoysiagrass large patch, dollar spot, spring dead spot St. Augustinegrass large patch, gray leaf spot 3
Diseases are stress induced turfgrasses need protection when they are stressed and growing slowly 4
brown patch of tall fescue caused by Rhizoctonia solani large patch of zoysiagrass caused by Rhizoctonia solani Rhizoctonia diseases are the most common and destructive in landscapes. 5
Brown patch is active when night temperatures are above 60ºF 6
Large patch is active when soil temperatures are below 70ºF 7
QoI Fungicides provide outstanding control of Rhizoctonia diseases 8
Fungicides Programs for Brown Patch Control Product Recommended Rate (/1000 ft 2 ) Recommended Interval (days) $/acre/day Disarm 0.18 fl oz 28 $5 Heritage 50WG 0.2 oz 28 $7 Heritage TL 1 fl oz 28 $7 Compass 0.2 oz 21 $10 Insignia 0.7 oz 28 $10 ProStar 2.2 oz 28 $10 9
Combination Products for Landscape Turf Headway azoxystrobin + propiconazole (Heritage + Banner) Armada trifloxystrobin + triadimefon (Compass + Bayleton) SysStar thiophanate-methyl + flutolanil (3336 + ProStar) 10
Keys to Successful Brown Patch Control initiate applications when night temperatures consistently exceed 60ºF spray in at least 2 gallons H2O per 1000 ft 2 for best results minimize nitrogen fertilization during summer avoid extended periods of leaf wetness mow regularly at 3 to 3.5 11
Pythium blight heavily shaded or poorly drained areas wet weather Gray leaf spot newly established turf (2-3 years) wet, cloudy weather Other tall fescue diseases that may develop in summer should be considered. 12
Turf Disease Diagnosis Services NC State Turf Diagnostics Lab (ncstateturfdiagnostics.com) Turffiles Disease ID Utility (www.turffiles.ncsu.edu) 13 13
Gray Leaf Spot Control in Tall Fescue Heritage TL (1 fl oz) Compass (0.2 oz) Headway (1.5 fl oz) Armada (1.2 oz) 3336 Plus (8 fl oz) Endorse (4 oz) Untreated 0 12.5 25.0 37.5 50.0 Kentucky 31 tall fescue seeded May 14 Treatments applied on 14 day interval beginning Jun 21 Data collected August 31 14
Pythium blight control in tall fescue 5 Pythium blight incidence (%) 4 3 2 1 0 Heritage TL Disarm Insignia Segway Subdue Untreated (2 oz) (0.37 oz) (0.9 oz) (0.9 oz) (1 oz) All treatments applied on 14 day interval Data collected 3 Aug 15
Kentucky bluegrass diseases are becoming more common in landscapes 16
Mixtures help to reduce brown patch injury 30.0 Coronado + Livingston Coronado + Midnight Brown Patch Incidence (%) 22.5 15.0 7.5 0 100:0 97.5:2.5 95:5 90:10 Mixing Ratio (% by weight) Mixtures planted in Oct 1999 Data collected on 29 Jun 2001 17
Mixtures are by weight, not number of seeds Tall Fescue 500 seeds/gram Kentucky Bluegrass 4,800 seeds/gram 18
Mixtures are by weight, not number of seeds Mix Ratio TF:KBG Tall Fescue Seeds (#) Kentucky Bluegrass Seeds (#) 90:10 204,000 218,000 95:5 216,000 109,000 97.5:2.5 221,000 54,000 19
Turfgrass populations may shift over time... 100 %TF in 1999 %TF in 2002 Percent Tall Fescue 75 50 25 0 100:0 97.5:2.5 95:5 90:10 Seed Ratio By Weight (TF:KBG) 20
Dollar spot is active when lows are above 50ºF and highs are below 90ºF 21
QoI Fungicides have dollar spot activity... Dollar Spot Incidence (spots/plot) 150 125 100 75 50 25 Disarm (0.18 fl oz) Heritage TL (1 fl oz) Compass (0.15 oz) Insignia (0.5 oz) Untreated 0 11 Jun 19 Jun 25 Jun 2 Jul 9 Jul 16 Jul 23 Jul 30 Jul 22
...but other products are often needed Dollar Spot Incidence (spots/plot) 80 64 48 32 16 Headway (1.5 oz, 14 day) Headway (2.25 oz, 28 day) Banner Maxx (1 oz, 14 day) Emerald (0.13 oz, 14 day) Untreated 0 15 May 6 Jun 13 Jun 19 Jun 26 Jun 5 Jul 10 Jul 23
Summer patch is active when soil temperatures are above 65ºF 24
Summer patch control in Kentucky bluegrass Banner Maxx (4 fl oz) Eagle 20EW (2.4 fl oz) Heritage 50WG (0.4 oz) Insignia (0.9 oz) Compass (0.25 oz) Headway (1.5 fl oz) Armada (1.2 oz) Bayleton (2 oz) Trinity (2 oz) Untreated Treatments applied May 2, May 29, and Jun 26 Data collected 10 Sept 0 7.5 15 22.5 30 25
Large Patch Control with Fungicides preventative timing is crucial initiate in fall when soil temperatures dip below 70ºF number of applications needed determined by threshold and pressure high pressure/low threshold 2 in fall, 1 in spring low pressure/high threshold 1 or 2 apps in fall 26
Large patch control in zoysiagrass Untreated Banner Maxx (4 fl oz) Heritage (0.4 oz) Bayleton (1 oz) Prostar (2.2 oz) Lawrence, KS Treatments applied Oct 8 Data collected Apr 24 0 5 10 15 20 25 30 35 Large Patch Incidence (%) 27
Large patch control in zoysiagrass Untreated Compass (0.25 oz) 3336 (4 oz) Bayleton (1 oz) Heritage (0.4 oz) 0 5 10 15 20 25 30 35 Large Patch Incidence (%) Lawrence, KS Treatments applied Sept 24 Data collected Apr 23 28
Resources for Fungicide Program Development 29