Organic Turfgrass Management: Disease Control Stategies

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1 Organic Turfgrass Management: Disease Control Stategies January 19, 2017 Bruce Clarke and Jim Murphy Dept Plant Biology and Pathology Rutgers University turf.rutgers.edu

2 Disease Calendar for Landscape Turf in New Jersey Dr. Bruce Clarke, Rutgers University turf.rutgers.edu [ Disease Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Anthracnose Brown patch Cool-season brown patch Dollar spot Gray leaf spot Leaf spot and melting-out Necrotic ring Spot

3 Disease Calendar for Landscape Turf in New Jersey Dr. Bruce Clarke, Rutgers University turf.rutgers.edu Disease Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Powdery mildew Pythium blight Red thread Rust Snow mold Stripe smut Summer patch

4 First Line of Defense Use the best adapted and disease tolerant species & varieties! Turfgrass Species Kentucky bluegrass Perennial ryegrass Tall fescue Fine fescues Hard fescues Use Varieties Tolerant to these Diseases Summer patch & Rust Gray leaf spot & Dollar spot Brown patch Red thread & Dollar spot Summer Patch

5 Primary Cultural Practices Mowing Fertilization Irrigation MUST do these well to maximize plant health and tolerance to diseases.

6 Primary Cultural Practices Mow at the optimum height and frequency. Fertilize properly for plant vigor and health for example, both deficient and excess N encourage diseases Maintain optimum soil ph both low and high soil ph can enhance certain diseases Light intensity and quality can influence surface wetness and plant vigor Deficient and excess irrigation can also influence disease

7 Dollar Spot Major hosts: Control : Perennial ryegrass and Fine fescues maintain adequate nitrogen fertility Some organic fertilizers and compost have been reported to reduce disease severity (Enhance microbes but difficult to separate from N effect) Proper water management critical Limit leaf wetness (< 9 hr) Dew removal in morning (mowing) Promote air movement (Courtesy R.W. Smiley)

8 Timing of Irrigation with Leaf Wetness Noon 6 pm Midnight 6 am Noon Formation of Dew & Guttation Water Natural Leaf Wetness Period Drying of Leaf Tissue

9 Management of Dollar Spot- continued Organic fertilizers and composts can reduce dollar spot but this is due more to increased N availability than to enhanced microbial activity in the soil n Microbial products containing Trichoderma harzianum (Root Shield), Bacillus lichenoformens (Ecoguard) can reduce dollar spot but often not to commercially acceptable levels alone; OMRI Listed n Use new improved turfgrass cultivars whenever possible ( RU Turf Proc.) n

10 Organic Disease Control Organic Soil Amendments (compost, compost teas) Soil Food Web rationale grow diverse population of microbes that compete with disease organisms Often difficult to separate the effects of microbial activity versus added nutrients since fertilization with inorganic N sources often provides the same reduction in disease Also uncertainty about whether the proper organisms are present in compost or tea

11 Making a Compost Tea ea1.htm Compost tea is made by soaking or steeping compost in water. 1. Keep aerated while steeping 2. Add molasses for food/primer (easily degraded carbon) 3. Other recipes add biostimulants, soluble nutrients, etc. 4. Should smell sweet and earthy, if foul do not use 5. Strain and use immediately Compost tea is applied either as a foliar application (sprayed on the leaves) or applied to the soil

12 Considerable Research Biological Disease Control Biological control agents (bacteria) such as Pseudomonas aureofaciens and Bacillus licheniformis Control acceptable at low to moderate disease pressure Control unacceptable at high disease pressure unless used daily high costs These agents used in combo with synthetic fungicides could reduce fungicide use but this is not organic

13 Commercial Organic Disease Control Products for Turf in USA Organism Trade Name Status OMRI Listed Trichoderma harzianum Gliocladium catenulatum Pseudomonas aureofaciens Turf Shield (BioTrek) Registered 1996 Yes Primastop Registration Application 5/97 Yes SpotLess Registered 1999 No Streptomyces lydicus Actinovate Registration Application 10/00 Yes Bacillus subtilis Companion Rhapsody Registered 2003 Yes Bacillus licheniformis Ecoguard Registered 2003 Yes Typhula phacorrhiza Registered 2010 No

14 Efficacy of Bacillus licheniformis for the Control of Dollar Spot in Crenshaw Creeping Bentgrass # Lesion Centers / plot Eco 20/14 Eco 20/14 Alt w/chipco 3 fl oz Eco 20/14 Thres w/chipco 3 fl oz Dac 3.2 oz /14 UTC 19-Jul 30-Jul 10-Aug 21-Aug Clarke et. al., 2002

15 Effect of Various Nitrogen Sources, Organic Amendments, and Biological Control Agents on Turfgrass Quality and Disease Development Treatment Formulation Rate/M Disease Severity July 17 Dollar Spot Brown Patch Dyrene 4F 4.0 fl oz 0.6 f 0.0 g Compost Plus G 10.0 lb 2.9 ef 0.8 fg Ringer lb 4.5 bcde 1.6 f Sustane lb 4.5 bcde 1.8 f Check bcd 5.4 a Urea 46% N 0.22 lb 6.3 ab 3.2 e Nitroform 38% N 5.26 lb 6.7 ab 4.2 bcde Number of infection center per sq ft, mean of 5 replications visual rating scale, where 0 = no disease, 5 = 50% infection, and 10 = Complete infection of all grass in plot; mean of 5 replication. (Sanders, Plant Pathology, PSU)

16 Endophyte mycelium in leaf sheath Endophyte mycelium in seed

17 Dollar spot on creeping red fescue E- E+

18 Summer Patch Major hosts: Kentucky bluegrass and Hard fescue Control: Increase mowing height Apply slow release fertilizer Alleviate stress on roots and promote root development Reduce soil ph (optimum 6.0) Overseed with resistant species / cultivars (Courtesy J.P. Kerns)

19 Characteristics of Fine Fescues (Festuca spp.) Species Lawn Mowing Height Summer Patch Disease Tolerance Dollar Spot Disease Tolerance Hard Fescue > 2 ½ Poor Good Chewings Fescue ½ 3 Good Fair Strong Creeping Red Fescue > 2 Good Poor

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22 Impact of Cultural Practices on Summer Patch Development u u u Compaction Nitrogen fertility & Soil ph Proper Mowing Height

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24 Effect of Compaction/Aerification on Aerificatio n Summer Patch Severity HVY (4X) HVY (2X) Compaction MOD (4X) MOD (2X) Non Comp Dp: S Dp: S & F Dp: F Sh: S Sh: S & F Sh: F None Mean Significant Difference = 1.2 cm

25 Mowing Height on Summer Patch University of Maryland University S-21 Kentucky Bluegrass Plot area damaged (%) a a a a a b a b b b Means followed by the same letter for each date are not significantly different at P=0.05 level.

26 Summer Patch Management u Aerify and Improve Drainage u Raise Mowing Height during Heat Stress u Overseed with Perennial Ryegrass, Tall Fescue, or Bentgrass ( u Fertilize with Acidifying N Sources, Avoid N Sources that increase ph u Maintain ph at or Below 6.0

27 Suppression of Summer Patch by the Commercial Biological Control Product, Companion 45 % Plot Area Symptomatic Untreated Companion Companion + Banner Companion + Heritage Banner Maxx Heritage 8/2/1999 8/9/1999 8/16/1999 8/23/1999 8/30/1999 9/6/1999 9/13/1999 9/20/1999 Rating Date Majumdar et al., 2000

28 Brown Patch Major hosts: Tall fescue Control: Use resistant cultivars Excessive nitrogen will increase disease severity Use slow release nitrogen sources Maintain adequate phosphorus and potassium levels Limit leaf wetness Dew removal (mow)in morning Promote air movement

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30 Red Thread Major hosts: Perennial ryegrass and Creeping red fescue Control: Apply nitrogen (quick-release source) Increase soil ph (6.0 to 6.5 optimum) Proper water management Increase air movement Mow with sharp blades

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32 Rusts Major hosts: Perennial ryegrass and Kentucky bluegrass Control: Select tolerant cultivars Apply nitrogen (quick-release source) Irrigate Mow regularly to remove visually apparent infected leaves

33 Mark Your Calendars Now for the Rutgers Landscape/ Sports Turf & Equipment Demonstration Field Day July 26, 2017 Adelphia, NJ