Treating vines after hail: Trial results. Bob Emmett, Research Plant Pathologist

Transcription

1 Treating vines after hail: Trial results Bob Emmett, Research Plant Pathologist

2 Treating vines after hail: Trial results Overview Hail damage recovery pruning trial Background and trial objectives Post-hail pruning treatments Trial design and setup Sequence of events and assessments Results and outcomes Pruning option costs and benefits Conclusions

3 Hail damage recovery pruning trial: Wine grapes Project Group Bob Emmett RWE Horticultural Pathology Research R W Emmett Pty Ltd, Mildura VIC Julian Connellan Murray Valley Winegrowers Inc., Mildura VIC (until January 2017) Michael Treeby and Dale Unwin Agriculture Victoria, DEDJTR, Irymple VIC David Dawes Avoca Vineyards, Pomona NSW

4 Hail damage recovery pruning options Main issue Severe hail storms in Sunraysia in November 2014 and 2016 during the vine post fruit set phase caused major crop losses More conclusive information on the benefits of immediate pruning in grapevine hail damage recovery programs was required Project objective Demonstrate the efficacy of post-hail pruning options Method Field trial in a typical mechanically hedged wine grape vineyard

5 Hail damage recovery pruning trial Trial site details Location: Pomona NSW Variety: Cabernet Sauvignon Trellis: Two-wire vertical Winter pruning: Hedged Vine and row spacing: 2 m and 3 m Row direction: East-west Hail event date, damage: 11 November 2016, severe Hail direction from: South Irrigation: Drip Nutrition: Standard Disease and pest control: Standard

6 Hail damage recovery pruning trial Post-hail pruning treatments and logic Unpruned Control (C)* Do nothing. Growth of new shoots from any remaining viable buds Machine Hedged (H)* Trim damaged shoots to 5-bud spurs. Growth of new shoots from lower more robust buds Hand Pruned (P) Prune damaged shoots to 2-bud spurs. Force growth of new shoots from lowest buds * Commercial options

7 Hail damage recovery pruning trial: Layout Trial (Randomised block design) Four replicates (R1-4) of adjacent blocks with C and H For each replicate, the first 5 sets of 3 single vine plots (randomised combinations of C, H and P) down rows were selected for assessment Vines of similar size were used in all plots Vineyard Four replicates (R1-4), each with a set of 3 adjacent rows of C and H Replicate 1

8 Hail damage recovery pruning trial Trial Assessments Values determined for two 0.5 m transects per single vine plot Plot (vine) length = 2.0 m Results presented as values per 1.0 m vine Some values assessed: 0.5 m 0.5 m Number of nodes on 20 damaged shoots 2.0 m Number of shoots Number of bunches on shoots from buds on 40 spurs/canes Weight of 10 bunches W N S E

9 Hail damage recovery pruning trial Sequence of events and assessments : Season with hail damage event Event or vine assessment Date Dormant vines machine hedged Mid Jul 2016 Severe hail damage event occurred 11 Nov 2016 Post-hail pruning treatments applied Mid Nov 2016 Hail damage on treated vines quantified (No. of damaged shoots per vine, no. of nodes per shoot) Vine regrowth quantified (No. of shoots per vine) Secondary crop on vine regrowth quantified (No. of bunches per vine) Fruitfulness of buds on dormant regrowth quantified (No. and percentage of fruitful buds per cane) Late Nov Dec Mar Jun 2017 Dormant vines machine hedged Late Jun 2017

10 Hail damage recovery pruning trial Sequence of events and assessments : Season following hail damage year Event or vine assessment Date Dormant vines machine hedged Late Jun 2017 Vine growth in spring quantified (No. of shoots per vine) Vine growth in early summer quantified (No. of shoots and bunches from buds on 40 canes per vine) Vine production at harvest quantified (Bunch and berry weights, fruit weight on 40 canes per vine) 9 Oct Dec Mar 2018 Dormant vines machine hedged Late Jun 2018 Fruitfulness of dormant buds on hedged vines quantified (No. and percentage of fruitful buds per cane) Late Jun 2018

11 Vine hail damage: Base-line Hail damaged vine growth (November 2016) Number of hail damaged green shoots per 1.0 m vine No significant difference: C = H = P C H

12 Vine hail damage: Base-line Hail damaged vine growth (November 2016) Number of nodes on hail damaged green shoots per 1.0 m vine Means significantly different: C > H > P Viability of buds on nodes uncertain

13 Vine regrowth after hail damage December December January March 2017

14 Vineyard regrowth after hail damage on 11 Nov November November December February 2017

15 Vine regrowth after hail damage Hail damaged vine regrowth (December 2016) Number of new green shoots per 1.0 m vine No significant difference: C = H = P

16 Vine regrowth after hail damage Hail damaged vine regrowth (March 2017) Number of bunches on new green shoots per vine (2.0 m vine) No significant difference: C = H = P

17 Vine regrowth after hail damage Hail damaged vine regrowth (June 2017) Percentage of fruitful buds on new dormant canes per cane No significant difference: C = H = P Assessment of dormant buds 1, 3, 5, 7, 9 and 11 on two dormant canes per vine by bud dissection and microscopic examination Data: Tim Brown, Bro-Kit Agronomy

18 Vine growth in season after hail damage Vine growth in spring (October 2017) Number of green shoots per 1.0 m vine No significant difference: C = H = P

19 Vine growth in season after hail damage Vine growth in early summer (December 2017) Number of green shoots on 40 spurs/canes per 1.0 m vine No significant difference: C = H = P Number of green shoots without bunches on 40 spurs/canes per 1.0 m vine No significant difference: C = H = P

20 Vine growth in season after hail damage Vine growth in early summer (December 2017) Number of green shoots with bunches on 40 spurs/canes per 1.0 m vine No significant difference: C = H = P Percentage of shoots with bunches on 40 spurs/canes per 1.0 m vine No significant difference: C = H = P

21 Vine growth in season after hail damage Vine growth in early summer (December 2017) Number of bunches on shoots from 40 spurs/canes per 1.0 m vine No significant difference: C = H = P Number of bunches per shoot on 40 spurs/canes per 1.0 m vine Significant difference: C = P; H > C?

22 Vine growth in season after hail damage Vine production at harvest (March 2018) Bunch size Weight of bunches (g) Large Average Small No significant difference: C = H = P (all comparisons)

23 Bunch size Vine growth in season after hail damage Vine production at harvest (March 2018) Weight of berries (g) Large Small No significant difference: C = H = P (all comparisons) Bunch size Number of berries per bunch Large Small No significant difference: C = H = P (all comparisons)

24 Vine growth in season after hail damage Vine production at harvest (March 2018) Calculated yield of fruit kg on 40 spurs/canes per 1.0 m vine No significant difference: C = H = P H C

25 Vine growth in season after hail damage Vine production at harvest (March 2018) Actual yield of fruit kg per 1.0 m vine NR Yield of machine harvested fruit from hedged rows was 18% higher than from unpruned rows Matter other than grapes (MOG) Score for machine harvested fruit MOG 2 MOG 1 NR More sticks/canes with fruit from unpruned rows, but no penalty incurred Data: David Dawes, April 2018

26 Hail damage recovery pruning trial: Data summary Vine dynamics after hail damage (values per 1.0 m vine) Assessment (unit per 1.0 m vine, date) C H P Means Different* Hail damaged shoots (no., Nov16) N Post-hail regrowth shoots (no., Dec16) N Spring shoots (no., Oct17) N Summer shoots (no. from buds on 40 canes, Dec17) Estimated yield (kg of fruit on shoots from buds on 40 canes, Mar18) N N Actual yield at harvest (kg of fruit, Mar18) NR NR * Means different: N = no; Y = yes; NR = no record

27 Hail damage recovery pruning trial Post-hail pruning options: Economic benefits? Vineyard benefit cost assessment Income (harvest 2018) Unpruned (C) Hedged (H) Harvest (Mar 2018) Yield (tonne per ha) Income ($ per ha) (Yield value of Cabernet Sauvignon $475 per tonne; no penalties for MOG) After hail damage event (Nov 2016) Costs ($ per ha) (Hedging of hail damaged vines) $12,445 $14,678 $0 $125 Return for each option ($ per ha) $12,445 $14,553 Benefit ($ difference between options) +$2,108 Data: David Dawes, April 2018

28 Hail damage recovery pruning trial Conclusions and comments (1) Two commercial post-hail pruning options were compared, i.e. no pruning and hedging. In the trial with replicated single vine plots, allowing for measurement variation, post-hail pruning treatments had no significant effect on vine recovery after damage or on vine growth and production in the following season. Well established vines with a history of winter hedging had adequate resources for rapid recovery after hail damage, regardless of post-hail pruning treatment. Shoots on unpruned vines were more tangled than shoots on hedged vines.

29 Hail damage recovery pruning trial Conclusions and comments (2) In the vineyard, yield of vines in hedged rows was higher than in unpruned rows at harvest In the assessment of economic benefits of options at the vineyard level, the cost of post-hail hedging was minor compared to income from higher yield at harvest in the following season. Vineyard yield in the season after hail damage was high and more even compared to most previous seasons. Different timing of hail damage in relation to stage of vine development could alter trial results and outcomes. The inclusion of replicated comparisons of untreated (control) and treated vines increased the amount and value of information from the field trial.

30 Hail damage recovery vine management Further Reading Dry, P. R. (1986) The effects of hail damage may carry over to next season. Australian Grapegrower and Winemaker 275: 22, 24. Krstic, M., Essling, M. and Sing, L. (2014) Managing grapevine post hail damage. Murray Valley Winegrowers Leaflet. 3 pp.

31 Hail damage recovery pruning trial Acknowledgements Financial assistance: Murray Valley Winegrowers Inc., Wine Australia, Agriculture Victoria DEDJTR Hail pruning trial site and management: David Dawes, Avoca Vineyards, Pomona NSW Satellite images (Slide 14 ) and assessments of bud fruitfulness and photos (Slide 17): Tim Brown, Bro- Kit Agronomy, Mildura VIC

32 Treating vines after hail: Trial results Questions and discussion