Turf - Fungicides for Disease Control

Snow mold season is upon us and turf managers should consider controls in areas with a history of snow molds. The following are fungicide recomendations for the major turf diseases in Delaware including snow molds.

These disease control recommendations contain fungicides that have proven to be effective under Delaware conditions when used according to instructions on the manufacturer’s label. Trade names appear for simplicity. No endorsement of such products, nor criticism of similar products not listed, is implied or intended. Numbers within parentheses represent maximum recommended spray intervals.

Anthracnose: Apply when the disease first appears. Repeat at 10- to (*)-day intervals: Banner (28), Bayleton (28), Cleary 3336 (14), Daconil (14), Compass (21), Eagle (21), Heritage (28), Manicure (14), Medallion, Thalonil (14), Rubigan (28), or Sentinel (28), Spectro (14).

Brown patch: Apply between June 1 and September 15 at 7- to (*) intervals: Banner (14), Chipco 26019 (28), Cleary 3336 (14), Compass (28), Curalan (14), Daconil (14), Eagle (21), Fungo (14), Heritage (28), mancozeb (14), Manicure (14), Medallion, Prostar (21), Sentinel (28), Spectro (14)Thalonil (14), thiram (10), or Touche (14).

Dollar spot: apply between May 15 and October 15 at 7- to (*)-day intervals: Banner (28), Bayleton (28), Chipco 26019 (28), Curalan (28), Daconil (21), Eagle (28), Emerald, mancozeb (14), Manicure (21), Rubigan (28), Sentinel (28), Spectro (14), Thalonil (21), Touche (28), or Vorlan (28).

Fairy rings: We have not been successful in controlling fairy ring with chemicals. For best results, aerify affected areas, maintain adequate soil moisture, and apply nitrogen to mask symptom expression. Prostar and Heritage have proven to be effective fungicides against some species of fungi that cause fairy rings. Use according to the manufacturer’s recommendations.
Gray leaf spot: Apply between July 15 and Oct 15 at 7- to (*)- day intervals: Banner (14), Chlorostar (21), Cleary 3336 (14), Compass (21), Daconil (10), Heritage (21), Manicure (10), Sentinel (28), or Spectro (14)

Leaf spot and melting-out: Apply when the grass starts to turn green in the spring. Repeat twice at 7- to (*)-day intervals: Chipco 26019 (28), Compass (21), Curalan (28), Daconil (21), Heritage (21), mancozeb (21), Manicure (21), Medallion, Thalonil (21), Touche (28), or Vorlan (28).
Necrotic ring spot: Apply Sept. to Nov. and April to June every 28 days as needed utilizing one of the following: Banner, Cleary 3336, Eagle, Fungo, Heritage, Rubigan, or Sentinel. Chemicals should be watered into the root zone for maximum effectiveness. Reapply thiophanate-methyl (Clearys 3336) every 14 days.

Powdery mildew: Apply between August 15 and October 15 at 10- to (*)-day intervals: Banner (28), Bayleton (28), Eagle (28), Rubigan (28), or Sentinel (28).

Pythium blight: Apply between June 15 and September 15 at 5- to(*)-day intervals: Aliette (14), Banol (21), Heritage (10), Koban (10), mancozeb (5), Prodigy (14), Subdue MAXX (21), Terraneb SP (7), or Terrazole (10). Apron may be used as a seed treatment to prevent damping-off. Mancozeb can be used to control this disease but is generally less effective than the products mentioned above.

Pythium root and crown rot: When the disease first appears, apply a contact fungicide such as Koban, mancozeb, or Terrazole in 5 to 10 gal of water. Irrigate the treated area immediately with 1/8 to 1/4 inches of water to ensure penetration into the soil. For best results, retreat the affected area within 5 to 7 days with an acropetal penetrant such as Aliette, Banol, Heritage, Prodigy, Quell, or Subdue Maxx. Chemicals should be watered into the root zone for maximum effectiveness.

Red thread: Apply when the daytime temperature in the spring stabilizes between 60 and 75o F. Repeat at 7- to (*)-day intervals: Banner (21), Bayleton (28), Chipco 26019 (14), Compass (21), Curalan (28), Eagle (14), Heritage (28), Rubigan (28), Sentinel (28), Touche (28), or Vorlan (21).

Rust: Apply between August 15 and October 15 at 7- to (*)-day intervals: Banner (28), Bayleton (28), Daconil (14), Eagle (14), mancozeb (14), Manicure (14), Sentinel (28), or Thalonil (14)

Slime molds: Mow off or rake out when they appear. General-purpose fungicides such as mancozeb may help reduce their appearance, but generally are not required.

Snow molds (Gray): Apply between November 15 and February 15. Repeat at 8-week intervals if necessary with Banner, Bayleton, Chipco 26019, Curalan, Daconil, Heritage, Manicure, PCNB++, Prostar, Rubigan, Sentinel, Teremec, Terraneb SP, Thalonil, or Touche.

Snow molds (Pink): Apply between November 15 and May 15. Repeat at 8-week intervals if necessary with Banner, Chipco 26019, Cleary 3336, Curalan, Fungo, Heritage, PCNB++, Spectro, Touche, or Vorlan.

Stripe smut: Either make one application of Banner, Bayleton, Cleary 3336, Eagle, Fungo, Rubigan, or Sentinel in mid-October; or apply in mid-May and then repeat 8 and 16 days later.

Summer patch (Fusarium blight syndrome): Apply in late-May, late-June and late-July in 4 to 5 gal water/1000 sq. ft for optimum control utilizing one of the following: Banner, Bayleton, Cleary 3336, Eagle, Fungo, Heritage, Rubigan, or Sentinel. Maintain soil pH at approx. 6.0. Chemicals must be watered into the root zone for maximum effectiveness.

Extracted from factsheet PP-07 "Fungicide Recommendations for Turfgrass" by Bob Mulrooney, Extension Plant Pathologist, UD Cooperative Extension. These recommendations were adapted for Delaware from information supplied by Drs. Bruce Clark and Ann Gould, Rutgers University Cooperative Extension and is gratefully acknowledged.