Organic viticulture research in Pennsylvania. Jim Travis, Bryan Hed, and Noemi Halbrendt Department of Plant Pathology Penn State University

Transcription

1 Organic viticulture research in Pennsylvania Jim Travis, Bryan Hed, and Noemi Halbrendt Department of Plant Pathology Penn State University

2 Organic production in the US; 1 st national certified organic production survey Response rate of 87 % Organic sales: $3.16 billion total - CA = $1.15 billion (*number one*) - WA = $282 million - PA = $213 million Number of organic farms: 14,540 total - PA sixth (586 or 4 % of the total) Organic acres = 4.1 million Most significant expense in organic = labor

3 Lake Erie Regional Grape Research and Extension Center Research Program: 3 areas of focus - Disease control in organic viticulture (*black rot*). - Transition of Concord grape vineyard to certified organic. - Soil and vine nutrition in organic grape production

4 Disease control (black rot) in eastern organic viticulture is accomplished through Understanding the pathogens and how they are affected by Site/Vineyard Selection Site Preparation Varietal Susceptibility Fungicide application Sanitation Canopy management

5 Major grape diseases in eastern viticulture Powdery mildew Downy mildew Black rot Phomopsis cane and leaf spot

6 Black rot symptoms Leaves Lesions appear 2 weeks after infection in spring Shoots Dark pycnidia within lesions

7 Black rot Tan (chocolate milk) spots on berries Berries turn dark brown with numerous pycnidia

8 Black rot Leaf and shoot tissue susceptible as long as still expanding. Fruit very susceptible from start of bloom to 3-4 (Concord) to 4-5 weeks (vinifera) after bloom. Fruit highly resistant by 6 (Concord) to 8 (vinifera) weeks after bloom.

9 Black Rot; Biology/Disease Cycle Over-winters in infected fruit (mummies) and wood (canes) on ground and in trellis. Primary cycle - spores released by rain, splashed to green tissue. Spore germination and infection dependent on wetness duration and temperature *New spring cluster stem infections may produce inoculum in 2-3 weeks fruit infection often results from these secondary inoculum sources.

10 How important are early spring cluster stem infections? 2007 pre-bloom shoot inoculations; Black rot cluster stem severity fruit rot severity. F r u i t r o t May 18 inoc. May 29 inoc. Pre-bloom cluster stem lesion development

11 2008 pre-bloom shoot inoculations; Black rot cluster stem severity fruit rot severity. F r u i t r o t May 8 inoc. May 15 inoc. May 25 inoc. Pre-bloom cluster stem lesion development

12 Site Selection: can determine overall disease pressure Maximum air movement and drainage (low RH) Maximum sunlight (no shade) Good soil drainage Adjacent land use Avoid proximity to water Soil quality: fertility, ph vigor control

13 How much does site matter? Vineyard 1 Vineyard 2 Concord Sunny, well drained, open 3 copper sprays each year 0.1 (2008) to 3 % (2009) crop loss to disease. Concord Wooded on 2 sides, wet, poor air flow, some rows shaded 6 (2008) and 7 (2009) copper sprays 16 (2008) to 73% (2009) crop loss to disease. *Vineyards are within 5 miles of each other.

14 Site Preparation Row spacing Vine spacing Row orientation Get weeds, diseases, and insect pests under tight control BEFORE transition.

15 Varietal Selection: what s important to disease control? Sensitivity to copper, sulfur: red hybrids, natives are sensitive. Predisposition to harvest bunch rots: avoid varieties with tight clusters; Disease susceptibility varies tremendously, particularly to black rot: - Vidal, Traminette, Elvira, Cayuga least susceptible to black rot. - Vitis vinifera most susceptible - Mid Atlantic is ground zero for grape pathogens (their turf); organic = use all tools to your advantage.

16 Varietal susceptibility to black rot; 2009 Leaf inoculations All white varieties; sulfur not an issue. Four French hybrids vs Vitis vinifera (Chardonnay) Chardonnay many times more susceptible.

17 Varietal susceptibility; Vidal trials in Erie PA Powdery mildew on fruit Downy mildew on fruit Powdery mildew on leaves Downy mildew on leaves

18 Organic chemical control trials Black rot control: Concord clusters Black Rot Control Champion 4 lb + lime Champion 2 lb + lime Lime Sulfur Citrex Yucca Milstop EF 400 GC-3 Serenade Neptunes Harvest

19 Organic chemical control trials Black rot control under high/low inoculum pressure: Niagara clusters High inoculum Low inoculum Champion 2 lb + lime Lime Sulfur Citrex Yucca Quillaja Serenade

20 Sanitation Reduce over-wintering inoculum sources (infected wood, fruit). Sanitize Trellis: Hand prune, removal of mummies Sanitize vineyard floor - Chop up prunings, infected debris - Bury (till, disk, hill) mummies, prunings. Sanitize vineyard: Remove from vineyard and bury or burn

21 Combining Sanitation (removal of mummies from trellis) and Fungicide for maximum black rot control Crop loss no fungicide copper lime sulfur Crop loss no fungicide copper lime sulfur (wet) (dry) Mummies No Mummies 0 Mummies No Mummies

22 Cultural control of black rot: inoculum reduction Infected fruit (mummies) are potent sources of inoculum in the trellis remove to the ground. (Wilson, Reddick 1909). Does timing of removal during dormancy (Oct, Nov, March) affect spore release next season (May, June, July)? Once on the ground, can soil amendments (compost, compost tea) further impact spore release?

23 Total ascospore counts (x 10,000) per mummy when dropped to soil at different times October drop November drop January March drop May June July a ab c c ab a a May June July b

24 2 1.5 Total ascospore counts (x 10,000) per mummy when treated with soil amendments. Mummies were placed in plots in November No amendment Compost Compost tea No amendment Compost Compost tea May June July 0 May June July

25 Total ascospore counts (x 10,000) per mummy when treated with soil amendments. Mummies were placed in plots in November a abab Pomace Chicken manure No amendment b b a bc May June July a ab Pomace Chicken manure Chicken x Pomace No amendment Not significant May June July

26 Canopy management: Pruning Mechanical pruning non selective, more dead, diseased wood = more inoculum Hand pruning (recommended) minimizes old, infected wood proper bud number

27 Spur prune vs cane prune (wine grapes) Spur pruning - requires cordons - retains more old wood - retains more inoculum (pathogen source) Cane pruning systems - Minimizes older wood - Minimizes inoculum

28 Canopy management: High wire, no tie - juice, FH wine -3 D Trellis systems Vertical shoot position -FH, vinifera wine - 2D (aeration, sunlight, fungicides)

29 Cluster zone leaf removal for bunch rot Reduces shading Improves aeration, sunlight, and pesticide penetration $ - can be mechanized Timing makes a big difference - Trace bloom: < compactness, > spray penetration = less rot Chardonnay, Before LR After LR Leaf removal timing % rot reduction over 3 yrs Trace bloom (reduces compactness by 23 %) wks post bloom 49 Veraison (8 wks post) 14 No Leaf removal *

30 2007 Results at FREC; Timing of Canopy Separation/Leaf Removal on Botrytis. % R O T Chardonnay Riesling Pinot Noir a* b b a*ab b a* b b - Early CS/LR most effective - Timing of LR more important than CS?

31 Summary; Organic disease management Start with good site selection Follow with good site prep Combine with varietal selection (low sensitivity to copper/sulfur, black rot, bunch rots) Don t rely so heavily on chemicals: copper/sulfur for diseases. Inoculum management/sanitation drop infected material to ground as early as possible, bury inoculum. Good trellis/canopy management Good weed control

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