Downy Mildew. Botrytis Bunch Rot

Transcription

1 1 Powdery Mildew Downy Mildew Black Rot Phomopsis Botrytis Bunch Rot ToRSVirus, Leafroll virus

2 Noemi O. Halbrendt Penn State University Fruit Research & Extension Center Biglerville, PA

3 Essential Components for Disease Susceptible Leaves/Fruit Disease Infection & Dev. Virulent Pathogen Favorable Weather/Environ.

4 NO Disease Susceptible Host Virulent Pathogen or Susceptible Host Favorable Env. Conditions

5 Disease or No Disease? Resistant Cultivar Virulent Downy Mildew Pathogen Grower s Action to Manage the Disease? Susceptible Host Favorable Weather Conditions Grower s Action to Manage Favorable Weather? Pathogen Control? Biology /Know your problem disease Sanitation /Cultural mngt Fungicides-decide what, if & when to use Efficacy What is working? Fungicide Resistance mngt. Follow the label Calibrated sprayer = good coverage Protectant mode? or Curative mode? $$$$$$ Monitor the weather conditions/ crop phenology to adjust spray sched / manage risk?

6 Downy Mildew Control 101 Know your Enemy - Disease Signs & Symptoms Biology / Disease Cycle Management / Control

7 Downy Mildew Fungus: Plasmopara viticola.

8 Downy Mildew: Important Disease of Grapes Affects susceptible grapes, every season, wherever they are grown Affects all green tissues of the vine Affects yield & juice quality Can affect next year s crop

9 Downy Mildew Signs and Symptoms: Tops of Leaves yellow oil spots (spring)... to reddish-brown angular spots (late summer) Lesions commonly form along leaf veins.

10 DOWNY MILDEW SIGNS AND SYMPTOMS: UNDERSIDE OF LEAVES Downy (cottony) sporulation White downy spore masses on the lower surface of the leaf.

11 Downy Mildew Signs and Symptoms: Tops & Bottom of Leaves White Downy Mildew fungal like growth on leaf underside (right) corresponds to yellow-brown lesions on upper leaf surface (left)

12 DOWNY MILDEW SIGNS AND SYMPTOMS: MATURE LEAF On older leaves, lesions are smaller and more angular as they are delimited by leaf veins. Late downy mildew infection, where the lesions of disease are restricted by the leaf veins giving rise to a tapestry-like appearance

13 DOWNY MILDEW: SHOOTS Tissues thicken Spores /White downy sporulation Tissues blacken and die Downy mildew on Chancellor

14 Systemic downy mildew shoot infection on Chancellor

15 DOWNY MILDEW: RACHISES Rachis thickens, curls (epinasty) White downy sporulation appears Clusters die

16 DOWNY MILDEW SIGNS AND SYMPTOMS: FLOWERS AND YOUNG FRUIT When infected pre bloom flowers/fruit White/brown and die

17 Downy Mildew: Fruit Sporangia in a young fruit White spore masses develop on infected berries 17

18 Downy Mildew: Fruit Death of berries associated with rachis infection by downy mildew Downy Mildew pathogen sporulating on infected berries 18

19 Do not mistake Powdery Mildew infection with Downy Mildew!!

20 Downy Mildew Powdery Mildew

21 Downy mildew on fruit : early berry infection

22 Downy Mildew: Older Fruit May not show sporulation Remain hard as healthy berries soften Infected berries redpink (red cultivars)

23 Downy Mildew: Older Fruit

24 Downy Mildew: Older Fruit mottled pale green (white cultivars

25 Downy Mildew: Biology / Disease Cycle Primary Phase Over-winters as oospores in infected leaves on vineyard soil Primary cycle; 2-3 weeks before bloom (5-6 leaf stage) to fruit set - spores released at > 0.1 rain, >52F - splashed from soil to canopy - requires wet leaf surface for infection

26 Oosporic Infection When does it first occur? : Observed first symptoms on Vitis interspecific hybrid cultivar Chancellor. In 25 of 26 years, first symptoms were observed after the following: Vines reach Eichorn and Lorenz stage 12; (4 5 Lvs) Rain event > 0.10 inches Temperature during rain > 52F Why is the vine not infected until this growth stage? David M. Gadoury, Department of Plant Pathology, Cornell University

27 E&L 5 E&L 7 E&L 9 Is the time of initial infection limited by vine susceptibility? E&L 12 No This shoot was inoculated At E&L stage 7 Timing of initial oosporic infection is more likely related to the timing of initial oospore maturity. David M. Gadoury, Department of Plant Pathology, Cornell University

28 When do fruit become resistant to infection? Geneva, New York y = LOG(x+1) r 2 = Answer depends upon climate. Relative disease severity Loxton, South Australia Inoculation time relative to bloom (Cumulative degree days, base = 50F In cold climate, ontogenic resistance is strongly expressed by degreedays (base = 50F) after bloom. In warmest climates, many berries are still highly susceptible at 400 degreedays after start of bloom. Protracted bloom in warmer climates results in protracted susceptibility, but this can be forecasted from local climate. David M. Gadoury, Department of Plant Pathology, Cornell University

29 Ontogenic Resistance of Berries Related to loss of infection sites as stomata are converted to lenticels. Berries infected just prior to onset of high level of ontogenic resistance may appear symptomless, and do not normally support sporulation. Shallow incisions made in the epidermis of such berries allow the pathogen to sporulate. David M. Gadoury, Department of Plant Pathology, Cornell University

30 Longevity of lesions? Relative sporulation (%) st event 2nd event 4th event Longevity is highly dependent upon occurrence of sporulation Number of sporulation events Time to 1st event or time between events is relatively unimportant. Central necrosis is a consequence of repeated sporulation, not age of infection. Number of sporulation events is primary determinant of longevity. Most lesions are productive for 2-3 events. David M. Gadoury, Department of Plant Pathology, Cornell University

31 Longevity of sporangia under vineyard conditions Sporangial germination (%) 100 A Number of hours sporangia exposed B C D E Observed 100 Y = X 80 R 2 = Expected With clear skies, under a variety of temperature and RH conditions sporangia died after 4-8 hrs. Survival was predicted well by existing DMCast model (based upon data of Blaeser and Weltzein). David M. Gadoury, Department of Plant Pathology, Cornell University

32 Longevity of Sporangia under Vineyard Conditions Sporangial germination (%) A B Number of hours sporangia exposed With overcast skies a high proportion of sporangia survived at least 24 hrs. Once again, survival was predicted well by existing DMCast model (based upon data of Blaeser and Weltzein, 1978). If it s not broke, don t fix it. David M. Gadoury, Department of Plant Pathology, Cornell University

33 Downy Mildew Dispersal Infected sucker

34 Downy Mildew: Biology/Disease Cycle Secondary Phase Repeating summer cycles - infections sporulate at night, >95% RH - spores wind blown, infect day generation time under ideal conditions Epidemics occur in warm, Hot, dry weather inhibits development; can reactivate if wet in fall 34

35 Downy Mildew: Risk ) over-wintering disease level from ) weather conditions - rainfall, temperature, 3) grape variety Early Season control -reduce fruit infection & leaf infection Late season control -prevent leaf infection, affect. fruit ripening, defoliation - Scout the vineyard/observe disease/weather 34

36 Downy Mildew Management Cultural Disease Control Chemical Disease Control

37 Downy Mildew: Cultural Control Good canopy mngt Improve air circulation to speed drying within canopies - appropriate trellis -site; good air drainage - row orientation to maximize air flow Spring cultivation to bury over-wintering sources of inoculum

38 Downy Mildew : Chemical Control High Disease Risk (High Suscept./Dis. History) - begin sprays 2-3 weeks before bloom - protect fruit until 4 weeks post-bloom - protect leaves through late summer if wet weather continues and disease is present Low Disease Risk (Low Suscept./Dis History) -start sprays at immediate pre-bloom - 1 to 2 post-bloom sprays

39 Downy Mildew: Chemical Control Ridomil - very effective - expensive - only controls downy - very prone to development of resistance Strobilurins - Abound most effective - Sovran moderately effective - Flint least effective - Pristine used to be very effective - Not effective in FREC Hybrid Vineyard trial; Still very LGERC Research Vineyard trial

40 Downy Mildew: Chemical Control Copper, mancozeb, captan - moderately effective - low/no resistance risk - inexpensive - copper may be toxic to some varieties Phosphorus acid (ProPhyt, Phostrol, Vigor Cal Phos) - effective - only controls downy - good post-infection activity - some foliar fertilizers contain phosphorus acid

41 2004 Downy Mildew: Chancellor clusters Efficacy of phos acid (PA) materials LEGERC, Erie, PA Severity of downy mildew PA very systemic PA very rain fast Low risk of resistance 5 applications: 2 pre, 3 post bloom. Prophyt registered for dm control % PA VCP sold as foliar nutrient, % PA unknown Higher level of ai in Prophyt? *Hed, B. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU,, Lake Erie Grape Research & Extension Center, Erie, PA.

42 2006 Downy Mildew: Niagara clusters Efficacy of phos acid (PA) and copper LEGERC, Erie, PA Severity of downy mildew PA (Prophyt) curative, copper (Champion WP) preventive PA very rain fast, copper subject to wash off Low risk of resistance 5 applications, 10 day intervals. *Hed, B. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU,, Lake Erie Grape Research & Extension Center, Erie, PA.

43 Severity of downy mildew Downy Mildew: Niagara clusters Efficacy of phos acid (PA) and copper LEGERC, Erie, PA 6 PA (Topaz) curative, copper 5 (Cueva) preventive PA very rain fast, copper subject to wash off Low risk of resistance 7 weekly applications *Hed, B. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU,, Lake Erie Grape Research & Extension Center, Erie, PA.

44 New Fungicides Downy Mildew Gavel 75DF (zoximide + mancozeb) Presidio 4SC (fluopicolide) Revus 2SC (mandipropamid) Tanos DF (famoxadone + cymoxanil) Zampro (Initium + Forum (dimethomorph) BASF, 2011 Ranman (Cyazofamid)

45 2008 Downy Mildew: Chancellor Shoots PSU FREC, Biglerville, PA % Inc.Shoots % Sev. Shoot % Control Nontreated Ck Zampro Forum Dithane Tanos Organic Revus Treatment Programs *Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA.

46 May 2009 Downy Mildew Infection Period * Penn State-FREC, Biglerville, PA Temperature (F) - Rainfall (in) - Leaf wetness (hours) Downy Mildew (Plasmopara viticola): Infection to the first appearance of symptoms approximately 4 days. Rain is the principal factor promoting epidemics. Temperature plays a less important role by retarding, accelerating the development of the disease. Green parts of vine and leaves are susceptible to infection. Rainfall not required for release of secondary spores.

47 June 2009 Downy Mildew Infection Period * Penn State-FREC, Biglerville, PA Temperature (F) - Rainfall (in) Leaf wetness (hours) Downy Mildew (Plasmopara viticola): Infection to the first appearance of symptoms approximately 4 days. Rain is the principal factor promoting epidemics. Temperature plays a less important role by retarding, accelerating the development of the disease. Green parts of vine and leaves are susceptible to infection. Rainfall not required for release of secondary spores.

48 - Rainfall (in) July 2009 Downy Mildew Infection Period * Penn State-FREC, Biglerville, PA Temperature (F) Leaf wetness (hours) * Downy Mildew (Plasmopara viticola) Infection to the first appearance of symptoms approximately 4 days. Rain is the principal factor promoting epidemics. Temperature plays a less important role by retarding, accelerating the development of the disease. Green parts of vine and leaves are susceptible to infection. Rainfall not required for release of secondary spores.

49 Temperature (F) Fig. 5 (C) August 2009 Downy Mildew Infection Period * Penn State-FREC, Biglerville, PA High Temp (F) Low Temp(F) Avg Temp(F) Leaf Wetness (hrs) Leaf wetness (hours) - Rainfall (in) Rainfall (in) Infection Period * Downy Mildew (Plasmopara viticola) Infection to the first appearance of symptoms approximately 4 days. Rain is the principal factor promoting epidemics. Temperature plays a less important role by retarding, accelerating the development of the disease. Green parts of vine and leaves are susceptible to infection. Rainfall not required for release of secondary spores.

50 DOWNY MILDEW Infection Periods (DMCAST) Temp. F Wetness Duration (hr) Temp. F Wetness Duration (hr)

51 Downy Mildew Programs, FREC Hybrid Vineyards, 2009* 1 Captan/Penncozeb/Ziram 2 Zampro-01 3 Zampro-02 4 Zampro-03 5 Zampro-04 6 Pristine 7 Revus 8 Presidio 11 Ranman/Phostrol -L 12 Ranman/Phostrol H 13 Phostrol only -H 14 No DM Fungicide Ck 15 Ranman only 16 Phostrol only-l(cr only) 17 Phostrol only-h (Cr only) *Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA. 51

52 2009 Downy Mildew Incidence Chancellor Wine Grape, FREC Hybrid Vineyard Chancellor Shoot - Leaves 1 Captan/Penncozeb/Ziram 2 Zampro-01 3 Zampro-02 4 Zampro-03 5 Zampro-04 6 Pristine 7 Revus 8 Presidio 11 Ranman/Phostrol -L 12 Ranman/Phostrol H 13 Phostrol only -H 14 No DM Fungicide Ck 15 Ranman only 16 Phostrol only-l(cr only) 17 Phostrol only-h (Cr only) *Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA. 52

53 2009 Downy Mildew Incidence Chancellor Wine Grape, FREC Hybrid Vineyard Chancellor Fruit Cluster 1 Captan/Penncozeb/Ziram 2 Zampro-01 3 Zampro-02 4 Zampro-03 5 Zampro-04 6 Pristine 7 Revus 8 Presidio 11 Ranman/Phostrol -L 12 Ranman/Phostrol H 13 Phostrol only -H 14 No DM Fungicide Ck 15 Ranman only 16 Phostrol only-l(cr only) 17 Phostrol only-h (Cr only) *Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA.

54 2009 Downy Mildew Incidence Vidal Wine Grape, FREC Hybrid Vineyard Vidal Fruit Cluster 1 Captan/Penncozeb/Ziram 2 Zampro-01 3 Zampro-02 4 Zampro-03 5 Zampro-04 6 Pristine 7 Revus 8 Presidio Treatment Programs 11 Ranman/Phostrol -L 12 Ranman/Phostrol H 13 Phostrol only -H 14 No DM Fungicide Ck 15 Ranman only *Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA. 54

55 2009 Downy Mildew Incidence - Wine Grapes FREC Hybrid Vineyard d c b a a a c b b b a a a a b a *,Halbrendt, N. O. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU, Fruit Research & Extension Center, Biglerville, PA.

56 Control of Downy Mildew on Chancellor Fruit Penn State LEGERC, Erie, PA Treatment and Rate/A Timing Incidence Severity Water /PM sprayed check 1, 2, 3, 4, 5, 6, c b Zampro11 fl oz/a + Sylgard fl oz/a 1, 3, 5, a 0.05 a Pristine 12.5 oz/a + Sylgard fl oz/a 1, 3, 5, a 0.02 a Revus 250 SC 8 fl oz/a + Sylgard fl oz/a 1, 2, 3, 4, 5, 6, a 0.02 a Presidio 4 fl oz/a 1, 3, 5, b 0.61 a Timing: 1 = 31 May; 2 = 7 Jun; 3 = 14 Jun (1 st post-bloom); 4 = 21 Jun; 5 = 29 Jun; 6 = 5 Jul; 7 = 12 Jul Means followed by the same letters within columns are not significantly different according to Fisher s LSD (P 0.05). (PM=Vintage, Endura, Quintec / da rot.) *Hed, B. & Travis, J.W Downy Mildew Trials on Hybrid Grapes. PSU,, Lake Erie Grape Research & Extension Center, Erie, PA.

57 2009 Fungicide performance trials for downy mildew control: Penn State FREC & LEGERC, PA High disease pressure for downy mildew; % crop loss in the water sprayed check. Pristine, Presidio, Zampro, Phostrol, Ranman, Revus (applied 7-14 days) All maintained excellent control of downy mildew on fruit all season in LGERC, Pristine did not work in Vineyard FREC. There was no phytotoxicity associated with any of the treatments.

58 Take Home Message Leaves can be infected all season; leaves less susceptible after fully expanding Clusters susceptible as soon as fungus is active Fruit resistant 2-4 weeks after bloom but... Rachises still susceptible after fruit are resistant (possibly until veraison)

59 Take Home Message Early fungicide sprays reduce the number of leaves that become infected Later sprays reduce severity of the infections that slip through

60 Take Home Message Serious fruit disease in mid summer consequence of events during early stages of fruit development, e.g., rainy weather and /or spray program problem

61 Take Home Message: Disease Resistance Alert Widespread resistance to strobies (Flint, Sovran, Abound, Pristine (Endura component of Pristine will not control downy) Resistance to strobies detected in some areas of MD, NC, and PA (Pristine not effective in 2009 FREC Vineyards Trials)

62 Take Home Message Manage fungicide resistance: alternate fungicides with different modes of action Poor spray coverage = low rates on susceptible tissues = poor control & increased resistance development

63 Gotta Question & Need to know more about Grape Downy Mildew? Noemi O. Halbrendt, PhD Penn State Fruit Research & Extension Center Biglerville, PA Phone: ext.222

64 Have a Good Vintage!!

65 Gavel 75 DF (zoxamide (8.3 %) + mancozeb (66.7 %) Protectant, preventive no curative activity Surfactants may improve spray deposition (see label) Combination of two chemistries for resistance management Same PHI as mancozeb (66 d) Labeled for downy mildew, Phomopsis Primarily a downy mildew material but should provide some control of black rot too (mancozeb), though not currently labeled for it. Limited to 8 applications per acre per season OR 15 lbs per acre /season Rainfast bonds to cuticle No supply problems anticipated with current mancozeb shortage (Gowan)

66 Presidio (fluopicolide) Risk of resistance high label requires it be applied as a tank mix with another chemistry for downy mildew. New chemistry Protectant, post-infection, antisporulant activity Only controls downy mildew In limited NY trials, has been very effective at 3 to 4 fl oz/a. Very rainfast: absorbed by plant tissue Not yet labeled in NY?

67 Revus 2SC (mandipropamid) New chemistry; Risk of resistance-moderate Protectant, post-infection, antisporulant activity Only controls downy mildew Very rainfast - absorbed by plant tissue Revus with a spreading/penetrating adjuvant (non-ionic surfactant).

68 Tanos DF (famoxadone (25 %) + cymoxanil (25 %)) Risk of resistance high label requires it be applied as a tank mix and alternated with another chemistry for downy mildew. Target site of action of famoxadone same as strobies rotate and mix with non-strobie (captan, mancozeb, copper). Protectant, curative, locally systemic activity Only labeled for downy mildew Very rainfast quickly penetrates plant tissue (within an hour)