SNOW MOLDS AND BLIGHTS

Transcription

1 SNOW MOLDS AND BLIGHTS Pink Snow Mold Fusarium Patch Gray Snow Mold Sclerotinia Patch Cottony Snow Mold Frost Scorch Pythium Snow Blight Microdochium nivale Microdochium nivale Typhula incarnata, T. ishikariensis Myriosclerotinia borealis (scald) Coprinus psychromoribidus Sclerotium rhizodes Pythium graminicola, P. vanterpoolii

2 Pink Snow Mold and Fusarium (Microdochium) Patch Pathogen: Grasses Affected: Microdochium nivale (Fusarium nivale) Annual bluegrass, bentgrass, Kentucky bluegrass, rough bluegrass, ryegrasses, tall fescue, fine leaved fescues.

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6 Fusarium (Microdochium) Patch Symptoms and Signs: Visible in spring and fall during cool, moist conditions. Most common on annual bluegrass and bentgrasses as pale yellow to reddish brown patches initially 1-2 in enlarging up to 12 in dia. Infection centers may coalesce into large areas. White, fluffy, mycelium at advancing margin, with slimy, orange to pink, spore masses. Severe damage to leaves and crown, natural recovery slow.

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10 Pink Snow Mold (PSM) and Fusarium (Microdochium) Patch (FP) Conditions Favored by wet conditions, high Favoring humidity and air temp. from 32- Disease: 55 F. Prolonged snow cover on unfrozen ground ideal for PSM, but necessary for FP. More severe when soil ph is neutral or alkaline. Lush, succulent growth in fall is very susceptible.

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14 Cultural Control of Snow mold Avoid fall fertilization that would encourage lush growth in mid- to late-october. Reduce soil ph below 7.0 whenever possible Maintain adequate K in late-fall to increase cold tolerance Reduce compaction and improve drainage Remove leaves and litter to avoid the buildup of moisture Use snow fences to prevent excess snow accumulation If covers are used on greens, treat turf with fungicides prior to installation

15 Snow Mold Control : Relative Effectiveness PSM GSM Aromatic hydrocarbons chloroneb -- 3 PCNB 4 4 Benzimidazoles thiophanate-methyl 3 -- Carboximides flutolanil -- 3 DMIs (Sterol-inhibitors) fenarimol 2 3 myclobutanil 2 -- propiconazole 3 2 triadimefon 2 3 Dicarboximides iprodione 3 3 vinclozolin 3 2 Nitrile chlorothalonil 3 3 Phenylpyrrole fludioxonil 31/2 -- Q 0 I (strobilurins) azoxystrobin, pyraclostrobin, trifloxystrobin 3 3

16 Pink / Gray Snow Mold : CBG Green - Pullman, WA # Patch/plot b a a a a Turfcide fl oz 4. Banner MAXX 1.3ME 2 fl oz 2. Compass 0.25 fl oz 5. Non-treated check 3. Medallion 50WP 0.5 oz F & N 56: T11 (2000)

17 Pink Snow Mold : KBG Fwy Pullman, WA % Disease c c b ab a a Chipco 26GT 2SC 4 fl oz + Terraclor 75W 4 oz 2. Chipco 26GT 2SC 4 fl oz + Heritage 50WG 0.4 oz F & N Tests 55:515 (1999) 3. Chipco 26GT 2SC 4 fl oz + Daconil Ultrex 82.5W 4 oz 4. Chipco 26GT 2SC 4 fl oz 5. Terraclor 75W 4 oz 6. Non-treated check

18 Pink Snow Mold : CBG / ABG Green - Denville, NJ % Disease bc c ab a a a Insignia 20WG 0.9 oz 2. Chipco 26GT 2SC 4 fl oz + Daconil Weather 6F 5.5 fl oz 3. Iprodione Pro 2SC 4 fl oz 4. Rubigan 1AS 8 fl oz 5. Daconil Ultrex 82.5WG 5 oz 6. Untreated check NJ Turf Proc 38: in Press (2007)

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20 Gray Snow Mold (Typhula Blight) Pathogens: Grasses Affected: Typhula incarnata, Typhula ishikariensis Bentgrasses, Kentucky, rough and annual bluegrass, ryegrasses, tall fescue, fine leaved fescues

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28 Gray Snow Mold (Typhula Blight) Conditions Favoring Disease: Mild outbreaks favored by air temp. from F and extended rainfall. Ideal conditions: snow falling on unfrozen ground, then persisting.

29 Effect of Bentgrass Species / Cultivars on Typhula Blight: Amherst, MA Ebdon, 2006, Plant Dis Mgm t Rpt 1:T039

30 Effect of Bentgrass Species / Cultivars on Typhula Blight: MA Ebdon, 2006, Plant Dis Mgm t Rpt 1:T039

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36 Most Effective Fungicides for the Control of Gray Snow Mold - Land O Lakes, WI Gray Snow Mold (%) Treatment 1 Untreated Check 42 Dicarboximide + DMI + PCNB 14 DMI + QoI + PCNB 43 DMI + PCNB 21 Dicarboximide + Nitrile + PCNB 47 DMI + Phenylpyrrole 23 DMI + Phenylpyrrole 48 DMI + Phenylpyrrole 39 Dicarboximide + Nitrile + PCNB 53 Carboximide + PCNB Turf Trends, Feb 06

37 Gray Snow Mold : KBG Fwy Breckenridge, CO % Disease c c a a ab b Heritage 50WG 0.4 oz + Daconil Ultrex 82.5WG 5 oz 2. Heritage 50WG 0.4 oz + Daconil Ultrex 82.5WG 5 oz 3. Turfcide 400 4L 12 fl oz 4. Compass 50WG 0.3 oz 5. Heritage 50WG 0.4 oz 6. Control F & N Test 55 : 517 (1999)

38 Preventive Control of Snow Molds on KBG / ABG Fwy: Vail 2004 Blunt and Fichtner Plant Dis Mgm t Report 1:T038

39 Pink / Gray Snow Mold : KGB Fwy Vail, CO % Disease d c b a ab Bayleton 50WP 2 oz + Turfcide 400 4F 8 fl oz 2. Medallion 50WG 0.5 oz + Banner MAXX 1.3ME 3 fl oz 3. Medallion 50WG 0.5 oz 4. Turfcide 400 4F 8 fl oz 5. Nontreated control F & N 57 : T30 (2001)

40 Pink / Gray Snow Mold : CBG Fwy - British Columbia % Disease d d d c b a Heritage 50WG 0.8 oz + Banner 1.1EC 4 fl oz 2. Heritage 50WG 0.4 oz + Daconil Ultrex 90WG 5.3 oz + Terraclor 75W 2.1 oz 3. Heritage 50WG 0.8 oz + Terraclor 75W 5.6 oz 4. Terraclor 75W 8.8 oz 5. Heritage 50WG 0.4 oz 6. Untreated control F & N Test 58 : T058 (2001)

41 Gray Snow Mold Control Suggestions : Univ. WI 1. The best combinations for snow mold control include a tank mixture of PCNB with a penetrant and/or contact fungicide with two applications split between October and November. 2. If you can t use PCNB, a combination of fludioxonil and propiconazole is a good choice. 3. In regions having moderate disease pressure, using a mixture of iprodione and chlorothalonil can provide good suppression of gray snow mold.

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