Fruit Crops Grapes. Diseases of Grapes and Fungicides Labeled for Control. Disease Fungicides a Efficacy b

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1 Diseases of and Fungicides Labeled for Control Disease Fungicides a Efficacy b Black Rot (Guignardia bidwellii) Symptoms: The black rot fungus attacks all parts of the grape plant. Leaf infection appears on the upper surface in early June as tiny reddish brown spots. The lesions enlarge to 1/4 inch or more in diameter and become brown with black borders. A ring of black fungal bodies develops near the outer edge of the brown area. Lesions on stems and tendrils are longer and darker than those on leaves. Stem lesions are narrow, sunken and often split lengthwise on the vine. Infections begin to appear on the fruit when the berries are about half grown. Initially, a small white spot forms that enlarges rapidly until the entire berry is rotten. Affected berries soon turn black, shrivel and dry up. Minute black fungal fruiting bodies develop on the surface of the dried fruit. On muscadines, lesions on berries are small, black and scabby. The fruit does not rot. Source of Inoculum: The fungus overwinters in mummified fruit on the vine and ground and within lesions on canes. Powdery Mildew (Uncinula necator) Symptoms: Produces a whitish gray, powderyappearing growth on affected tissues. All green tissues are susceptible. Infection of young expanding leaves causes them to become distorted. Infection of blossoms results in poor fruit set. Infection of berries results in splitting or a netlike pattern on the surface. Source of Inoculum: The fungus overwinters in dormant buds or on other vine surfaces. Spores are wind dispersed. Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) Captan, Captec (captan) c Dithane, Manzate, Penncozeb (mancozeb) Elite, Orius (tebuconazole) fixed copper (copper hydroxide, copper sulfate, cuprous oxide) Flint (trifloxystrobin) Maneb (maneb) ManKocide (copper hydroxide + mancozeb) Rally, Eagle (myclobutanil) Sovran (kresoxim methyl) Topsin, T Methyl, Thiophanate Methyl (thiophanate methyl) Ziram (ziram) Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) Elevate (fenhexamid) c Elite, Orius (tebuconazole) Endura (boscalid) fixed copper (copper hydroxide, copper sulfate, cuprous oxide) Flint (trifloxystrobin) ManKocide (copper hydroxide + mancozeb) Rally, Eagle (myclobutanil) Procure (triflumizole) Quintec (quinoxyfen) Rubigan (fenarimol) Sovran (kresoxim methyl) sulfur (sulfur) Topsin, T Methyl, Thiophanate Methyl (thiophanate methyl) Vangard (cyprodinil) c

2 Disease Fungicides a Efficacy b Botrytis Bunch Rot (Botrytis cinerea) Symptoms: Infected blooms rot and dry out. Infected berries develop an off color and either dry out (during dry weather) or burst (during wet weather). Source of Inoculum: The fungus overwinters on canes or in buds. Spores are wind dispersed. Downy Mildew (Plasmopara viticola) Symptoms: This is primarily a disease of bunch Muscadines are relatively resistant. All green parts of the vine are susceptible. Leaf lesions are yellowish to reddish brown and may appear angular if they are delimited by veins. Infected shoot tips tend to curl. Leaves and shoots become covered with white mycelium. Berries appear grayish and are covered with the downy feltlike growth of the pathogen. Source of Inoculum: The pathogen overwinters in infected leaves. Disease development is boosted by wet weather. Abound, Heritage, (azoxystrobin) c Adament (tebuconazole + trifloxystrobin) Elevate (fenhexamid) Elite, Orius (tebuconazole) Endura (boscalid) c Flint (trifloxystrobin) c Procure (triflumizole) c Rovral, Iprodione, Nevado (iprodione) Scala (pyrimethanil) Sovran (kresoxim methyl) c Topsin, T Methyl, Thiophanate Methyl (thiophanate methyl) Vangard (cyprodinil) Ziram (ziram) c Aliette (aluminum tris) Abound, Heritage (azoxystrobin) Adament (tebuconazole + trifloxystrobin) c Captan, Captec (captan) Dithane, Manzate, Penncozeb (mancozeb) fixed copper (copper hydroxide, copper sulfate, cuprous oxide) Flint (trifloxystrobin) c Fosphite, Fungi phite, Helena Prophyt, Phostrol, Topaz (phosphite) Maneb (maneb) ManKocide (copper hydroxide + mancozeb) Presidio (fluopicolide) Revus (mandipropamid) Ridomil Gold Copper (mefenoxam + copper hydroxide) Ridomil Gold MZ (mefenoxam + mancozeb) Sovran (kresoxim methyl) Ziram (ziram)

3 Disease Fungicides a Efficacy b Anthracnose (Elsinoe ampelina = Sphaceloma ampelinum) Symptoms: Fruit infections have light gray centers and reddish brown borders, resembling a bird s eye. Stem lesions are similar in color and sunken, with slightly raised borders. Leaf spots are gray with dark borders. Later, the center of the lesion drops out, giving a ragged effect. Badly infected leaves become distorted and curl down. Source of Inoculum: The fungus overwinters in infected fruit on the ground or in infected shoots. Rally, Eagle (myclobutanil) Pierce s Disease (Xylella fastidiosa) Symptoms: This is a disease of bunch Muscadines are resistant. Symptoms may vary, but generally are characterized by a scorching of the leaf margins. Grape clusters wilt and dry; bud leaves are slow to develop and show water stress during dry periods. Source of Inoculum: The bacterium survives in infected vines and other hosts. It is transmitted by a number of leafhoppers. Control: No practical control is available. Limiting the spread of the insect vector and destruction of wild weed hosts have had limited success. Destroy infected plants. a Trade name (chemical name) b Efficacy ratings are on a 1 5 scale, where 5 (+) is the most effective and 1 (+) is the least effective. Ratings are taken from the Southeast Regional Grape Integrated Management Guide of the Southern Region Small Fruit Consortium ( c For disease suppression or to aid in disease control.

4 Fungicide Spray Schedule for a Developmental Stage Timing Disease(s) Pre bloom Bloom Post bloom Summer cover sprays Bud break to bloom, Every seven to 10 days percent bloom First cover Every seven to 10 days Black rot, powdery and downy mildews Black rot, Botrytis and powdery mildew Black rot and powdery and Downy mildews Black rot, Botrytis and other fruit rots, powdery and downy mildews Pre harvest days before harvest Botrytis and other fruit rots Post harvest Every days until frost Downy mildew a For more information, see the Southeast Regional Muscadine Grape Integrated Management Guide and the Southeast Regional Bunch Grape Integrated Management Guide of the Southern Region Small Fruit Consortium (

5 Fungicides Labeled for Use on Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) aluminum tris Aliette 80 WDG day interval; no more than seven applications per ; do not mix with copper fungicides (see label) azoxystrobin Abound, Heritage 2.08 F 50 W fluid to 14 day interval; no more than two sequential four applications or 2.88 quarts per acre per boscalid Endura 70 WDG 4.5 or 8 10 to 14 day interval; no more than three sequential five applications or 25 per acre per 7 14 boscalid + pyraclostrobin Pristine WDG or (see label) See label as some varieties may be injured. 10 to 14 day interval; no more than two sequential six applications or 69 per acre per captan Captan, Captec 50 W 80 WDG 4F quarts See label. No more than 24, 15 or 12 quarts per acre per year, respectively M4 0 copper hydroxide Champ, Champion, Kocide, Stretch Metallic copper equivalent 2.16% 15% 24.4% 30% 35% 37.5% 40% 50% 2 4 pints pints pints See label; some varieties are sensitive to copper, discontinue if injury appears; do not use in spray solution with ph less than 6.5 M1 1 2

6 Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) copper hydroxide + mancozeb ManKocide WP 2.5 See label; no more than 128 per acre per M1 + M3 66 copper sulfate Cuprofix Metallic copper equivalent 20% 40% cyprodinil Vangard 75 WDG 10 or 5 10 when tankmixed fenarimol Rubigan 1 EC 2 6 fluid See label; some varieties are sensitive to copper, discontinue if injury appears; do not use in spray solution with ph less than 6.5 See label; seven day interval; no more than 20 per acre per See label; no more than 19 fluid per acre per fenhexamid Elevate 50 WDG 1 See label; no more than two sequential 3 per acre per fluopicolide Presidio 4 SC 3 4 fluid Must be tank mixed with another fungicide registered for this use; 10 day interval; no more than two sequential four applications or 12 fluid per acre per M iprodione Rovral, Iprodione, Nevado 50 W 4FL pints See label! Make only four applications per for wine grapes; only one application per for table grapes (early to midbloom); do not graze livestock in treated vineyards! 2 7 (wine grapes) NA (table grapes) kresoximmethyl Sovran 50 WDG or See label; higher rates are for downy mildew; no more than two sequential four applications or 25.6 per acre per 11 14

7 Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) mancozeb Dithane, Manzate, Penncozeb 4 F 75 DF 80 WP quarts See label; no more than 19.2 quarts, 25.5 or 24 per acre per, respectively M3 66 mandipropamid Revus 2.08 F 8 fluid Seven day interval; no more than two sequential 32 fluid per acre per maneb Maneb 75 DF 80 WP See label; seven to 10 day interval; no more than 19.2 per acre per M3 66 mefenoxam + copper hydroxide Ridomil Gold Copper WP 2 See label; no more than four applications per 4 + M1 42 mefenoxam + mancozeb Ridomil Gold MZ WP 2.5 See label; no more than four applications per 4 + M3 66 myclobutanil Eagle, Rally 20 EW 40 W 6 10 fluid 3 5 See label; no more than 46 fluid or 1.5 per acre per year 3 14 phosphite (phosphorous acid salts) Fosphite, Fungi phite, Helena Prophyt, Phostrol, Topaz Phosphorous acid equivalent (lb/gal) quarts 1 3 quarts 2 4 pints pints See label pyrimethanil Scala 600 SC 18 fluid (alone) 9 fluid (tank mix) quinoxyfen Quintec 2.08 F 3 4 fluid or fluid See label; no more than 36 fluid per acre per ; use lower rate only when tank mixed with another product labeled for Botrytis control Seven to 14 day or 14 to 21 day intervals; no more than five applications or 33 fluid per acre per crop

8 Common Trade Formulation(s) Rate(s) (per Acre) Comments FRAC Group PHI (days) sulfur IAP Dusting Sulfur, Liquid Sulfur Six, Microthiol Disperss, Super Six Liquid Sulfur, Thiolux Jet, 80% Thiosperse, Wettable Sulfur 6 F 80% WP 90% WP 98% WP 1 8 pints Concord and Labrusca type grapes may be injured by sulfur; do not use when hot or when temperatures are expected to be above 90 degrees F over the next three days; do not use within two weeks of an oil spray; see label for application intervals M2 1 tebuconazole Elite, Orius, 45 DF 4 See label; Seven to 21 day interval; no more than 2 per acre per 3 14 tebuconazole + trifloxystrobin Adament 50 WG 3 6 See label; no more than six applications or 48 per acre per ; do not use on Concord grapes thiophanatemethyl Thiophanat e methyl, T Methyl, Topsin 70 WP 85 WDG See label; no more than 4 or 3.2 per acre per, respectively 1 14 triflumizole Procure 50 W 480 SC fluid 14 to 21 day interval; no more than 32 or 32 fluid per acre per 3 7 trifloxystrobin Flint 50 W See label; 14 to 21 day interval; no more than two sequential applications; no more than six applications or 24 per acre per ; do not use on Concord grapes ziram Ziram 76 DF 3 4 Seven to 14 day interval; no more than 28 per acre per M3 21