Management and research of fruit rot diseases in vineyards Bryan Hed, Henry Ngugi, and Noemi Halbrendt Department of Plant Pathology Penn State University
Botrytis Bunch rot Late season condition, ripening. Complex cluster rot involving many factors Compactness determines susceptibility and spread within cluster (berry-berry contact)
Colonizes/Over-winters on any plant debris in the vineyard. Spores present all season; most numerous during ripening Spores spread by rain/wind Botrytis; Biology Germination, infection, sporulation take place at > 90% RH
Botrytis; Biology Opportunistic pathogen - prefers injured, dead, and/or senescing tissue Immature berries relatively resistant to rot - rot can occur if conditions are very wet. Latent infections - infect berries/pedicels through senescent blossoms; incidence increases throughout the season; most remain dormant.
Botrytis; Biology After veraison... Latent infections may activate (injury?) Berries increasingly more susceptible to direct invasion or through wounds Retention of floral debris can contribute significantly to bunch rot development in tight clusters.
Botrytis; Chemical Control: all are good/excellent protectants, pm control/suppression Vangard (cyprodinil), Scala (pyrimethanil) Elevate (fenhexamid) Rovral (iprodione) - efficacy improved with surfactant Strobilurins - Flint effective at 3 oz rate, Pristine at 18.5-23 oz rate. Endura (boscalid) - effective at Botrytis rate (8 oz); less effective at powdery mildew rate (4.5 oz) Switch (new) cyprodinil (systemic) + fludioxonil (contact) Rotate, rotate, rotate!!!!!!!!!!!!!!!!!
Botrytis; Chemical Control Timing Bloom; control latent infection if weather wet. Pre-close; last chance to reach inside of compact cluster. Veraison; protect from direct invasion from outside cluster. Pre-harvest; controls spread until harvest, especially if wet.
Botrytis; Integrate Cultural Control Varietal selection? Improve aeration and light penetration around clusters - leaf pulling, shoot thinning, shoot positioning Avoid excessive nitrogen Wound management
Check 2007-09: Chardonnay, Rot control chemical only vs integrated ( + leaf removal) Fisher s Protected LSD (a 0.05). % R O T + Leaf removal Hand Mechanical # 50 % rot reduction w/lr vs 2 fung: but significant only in 08 Early LR more effective than late
Botrytis bunch rot Management Wound management Intact berry skin most important barrier to opportunists. Latent infections may not activate if ripening berries remain intact. Control wounds by controlling birds, insects, powdery mildew, compactness
Botrytis; Cluster compactness Major predisposing factor - wounds from overcrowding - greater berry to berry contact; - poor spray penetration in tight clusters - poor climate within cluster Research focus: treatments that reduce cluster compactness. Compactness : # berries/cm rachis
Effects of cluster compactness on fungicide coverage of fruit clusters Vignoles clusters sprayed with orange spray paint. % C O V E R A G E Compactness as number of berries/cm of rachis. One berry/cm change in compactness = 2.8 % change in coverage
Cluster compactness can be reduced by Cluster zone leaf removal at trace bloom 20 % Reduction (range 10-30 %)
Check % R O T 2007-09: Chardonnay, Rot control chemical vs integrated (+ leaf removal + reduced compactness) Trace LR combines open cluster zone with reduction in compactness + Leaf removal Hand Mechanical Fisher s Protected LSD (P 0.05). 73% rot reduction vs 2 fung: # significant in 2008 # significant in 2009 ## #
2 fung * + trace + 2-3 wks post + veraison 2 fung 2 fung * + trace + 2-3 wks post * + trace + 2-3 wks post + veraison + veraison Check Check Check 2007-2009 Cluster Effects 100 80 2 Berries per cluster Berry weight (grams) Berries/cm (compactness) 15 60 10 1 40 20 0 25 % * 0 * 5 0 20 % * *
Check Check Check Yield (kg) per vine (08-09) 6 5 4 3 2 1 0 2 fung * + trace 25 % * + 2-3 wks post 5 + veraison 120 100 80 60 40 20 0 Cluster weight 2007-2009 (grams) 15 % 2 fung * + trace * * + 2-3 wks post + veraison Yield Effects 4 3 2 1 24 % Average yield (tons/a; 08-09) 0 2 F * + trace + 2-3 wks post + veraison
LR Increases initial management costs by $150/A (hand) OR $40/A (mechanical) but LR decreases time for hand harvest ($?) Yield loss increases by 24 % with TBLR - Is this in line with expected yields for premium quality Chardonnay? TBLR = 6-7 % improvement in spray penetration (for all diseases). How much is this worth?... 48% improvement in Botrytis control over post set LR. Pro$ and Con$ of leaf removal timing Average estimated $$$/A for Botrytis control Cost of hand LR increases with later timing; TBLR 34 and 13 % less costly than veraison and post fruit set LR. Mechanization of TBLR? Rot reductions increase with earlier timing. 73 % less rot with TBLR vs No LR 45 % less rot with post set LR vs No LR 8% less rot with veraison LR vs No LR Other diseases?
Pro$ and Con$ of leaf removal/timing Fruit less likely to suffer sunburn with earlier LR. Juice brix generally increases with earlier timing (higher quality?). No data on Chardonnay flavor components with TBLR. Effects of weather decrease with earlier timing; more consistent production of healthier grapes. Quality: can we get more money from healthier grapes? What is the value of reducing fungicide use, delaying resistance? How much value can we place on our reputation?
Pennsylvania Trials 8 vineyard locations: - 6 Commercial vineyards in 3 counties (Erie (2), Adams (1), Lancaster (3) - 2 PSU vineyards; FREC (Biglerville), LERGREC (North East). 4 premium wine varieties: Pinot Gris, Pinot Noir, Chardonnay, Riesling, Vignoles Treatments in each vineyard: - Growers standard (GS with/without fruit set LR) - GS + LR (trace bloom)
Chardonnay: % reduction in compactness from trace bloom leaf removal Possible issues: Timing? Differences in management?
Chardonnay: % reduction in rot severity from trace bloom leaf removal Possible issues: Timing? Differences in management? Control of birds, GBM?
Chardonnay: % reduction in rot severity from trace bloom leaf removal: overall average Possible issues: Timing? Differences in management? Control of birds, GBM?
Conclusions to date; TBLR reduces rot severity, fruit set, compactness, cluster weights but not always significant. Timing issues? GS + trace LR GS alone 2011: No serious effects on return bloom (fruitfulness) after one year of treatment
Pinot Noir/Gris: % reduction in compactness from trace bloom leaf removal Possible issues: Timing? Differences in management?
Pinot Noir/Gris: % reduction in rot severity from trace bloom leaf removal Possible issues: Timing? Differences in management? Control of birds, GBM?
Pinot Noir/Gris: % reduction in rot severity from trace bloom leaf removal: overall average Possible issues: Timing? Differences in management? Control of birds, GBM?
Conclusions; Pinot Gris/Noir TBLR reduces rot severity (but not always significant). 2011: No serious effects on return bloom (fruitfulness) TBLR reduces fruit set, compactness, cluster weights.
What s next Pinot Gris; TBLR = pull 5-6 leaves (Stefano Poni) Cost effectiveness of TBLR - By hand; 13 % less time than LR at set - can it be mechanized?... Collard pulsed air system - LR in fruit zone at flower separation - little/no damage to inflorescences - No blades; uses air bursts to shatter/remove leaves, bloom trash.
Review of 2011 Hurricane Irene Tropical Storm Lee *Wikipedia*
Observations of 2011 Well timed sprays during ripening crucial Early harvest beneficial; escaped Irene/Lee. Cultural controls (leaf removal, shoot thinning, etc) reduced the effects of excessive rainfall. Chemical + Cultural controls essential.
What about 2012? Farm as if you expect the worst: chemical/cultural controls are insurance policies best applied proactively. If you re going to grow rot prone varieties - sanitation to reduce over-wintering inoculum - full chemical programs, rotate chemistries - fully integrated programs: leaf removal a MUST for tight clustered varieties. - control wounding: powdery mildew, birds, berry moth, compactness? - early harvest? Can t control the weather, but can reduce its effects on rot development.
Special thanks to the Pennsylvania Wine Marketing and Research Board for funding.