Grape Rootstocks for Southwest Texas

Grape Rootstocks for Southwest Texas Texas A&M AgriLife Extension Service, February 14, 2013 Extension Specialists: Mark Black, Extension Plant Pathologist, Uvalde; James Kamas, Extension Horticulturist, Fredericksburg; David Appel, Extension Plant Pathologist, College Station Acknowledgements: Travis Helm, CEA AG-NR Real County, Alfred Sanchez, Liza Silva, B. J. Perez, Larry Stein and Rick Machen, Uvalde; Andrew Labay, Adam Elrod, Keisha Migura and Marvin Nebgen at Fredericksburg Cooperators: Frio Valley Vineyards, Leakey; Dustin Steubing and Trey Bader, Cedar Beetle Land Clearing, Inc., Leakey; Becker Vineyards, Stonewall Problem: Pierce s disease, cotton root rot disease, and poor soil can kill wine grapes in two-thirds of Texas Objective: Rank grape rootstocks for survival from diseases and high ph thin soil in Southwest Texas Strategy: Monitor replicated trials of selected grafted rootstocks The warm-climate bacterium Xylella fastidiosa subsp. fastidiosa causes Pierce s disease (PD), a vascular disease of wine and table grapes. The endemic bacteria are moved from plant to plant by several xylem-feeding insects including glassy-winged sharpshooter (GWSS, Homalodisca vitripennis). European wine grape varieties are highly susceptible and stress (drought, fruit load) accelerates symptom development and vine death. The warm-climate fungus Phymatotrichopsis omnivora causes cotton root rot (CRR) of grape and over 2,000 other plant species. The fungus survives in high ph soils found in two-thirds of Texas. Own-rooted European wine grape varieties and many hybrid rootstocks are susceptible and are also unable to absorb sufficient iron (Fe) and other nutrients from calcareous high ph soils that predominate in Southwest Texas. The stress of heavy fruit load accelerates vine death. Crown gall (CG), caused by the bacterium Agrobacterium vitis, may occur in wine grapes after a winter freeze event. The bacterium is commonly systemic in nursery stock. A hard freeze and wounding associated with routine vineyard management can trigger galling and vine die-back. Incomplete winter dormancy and excessive soil moisture in winter are predisposing factors.

We have rootstock comparison data from four sites in 2012: A, PD-tolerant scion varieties grafted on PD-tolerant rootstocks (Leakey, thin soil on fractured limestone, planted 28-29Apr11, own-rooted scions as controls, five-plant plots, five replications, drip irrigation, small wood pruned back to two buds), B, similar experiment with Florilush instead of Tampa (Uvalde, planted 31May-1June12, no own-rooted controls, five-plant plots, three replications, furrow irrigation), C, PD-susceptible Sangiovese on selected rootstocks (Leakey, planted 27Sep11, ten-plant plots, five replications, drip irrigation, small wood left up to cordon wire), and D, same experiment (Stonewall, planted 20-21Sep11). Data collected were nutrient deficiency symptoms, relative growth rates, or mortality and cause. Tests A and C were not treated with imidacloprid. Test B received imidacloprid by drench soon after transplanting. Test D was not treated, but some nearby grapes received imidacloprid. Results Typical symptoms of PD were not observed in any experiment at the Leakey site. Test C (Leakey) leaf composites within plots were all negative for X. fastidiosa serology (ELISA). Glassy-winged sharpshooter, the presumed most common vector of X. fastidiosa, was present at the site in 2012 based on sightings in the experimental vineyard and catches on yellow sticky traps (Table 1). Table 1. Adult glassy-winged sharpshooter (Homalodisca vitripennis)(gwss) insects on yellow sticky traps placed at 4 to 5 ft heights and evaluated on six dates in 2012 in or near the experimental vineyard near Leakey, Texas. GWSS/trap for period ending Location No. traps Late 18Jul 31Aug 20Sep 5Nov 6Dec 27Feb13 North row of vineyard 3 1.3 3.7 1.7 1.7 0 0 0 West fence >50 ft from a vine 3 0.3 2.0 1.0 0.3 0 0 0 South fence >400 ft from a vine 1 1.0 1.0 0.0 1.0 0 0 0 A, PD-tolerant scion varieties grafted on PD-tolerant rootstocks, Leakey. Across rootstocks on 22June, Blanc du Bois had less growth than the other two scions while Black Spanish had more mature leaves with nutrient deficiency symptoms (Table 3). Across scions on 22June, own-rooted and Tampa had the least growth, while Tampa, own-rooted, and Kober 5BB had more mature leaves with deficiency symptoms. There was a significant interaction between scion and rootstock and growth was best for Chambourcin/Dog Ridge and Black Spanish/1103P. There were highly significant differences among replications, indicating the variable soil at the site.

Across rootstocks on 20Sept, Blanc du Bois and Black Spanish had more growth than Chambourcin, but many Chambourcin plants were chip budded early in 2012 and growth is expected to be similar in the future (Table 3). Across scions on 20Sept, Kober 5BB and Paulsen 1103 had more growth than other rootstocks. The three scions had similar overall deficiency symptoms and cotton root rot mortality. Dog Ridge, Paulsen 1103, and Kober 5BB had the least deficiency symptoms and cotton root rot mortality among rootstocks. Own rooted and Tampa treatments had the most cotton root rot (Table 2). Leaf petiole samples (late June, older mature leaves with deficiency symptoms, young mature asymptomatic leaves) and soil samples (late July, replications 1, 5) revealed very low soil phosphorus levels at this site. Deficiency symptoms were consistent with rare reports of P deficiency in grape. Because phosphorus is important for root growth, uptake of other minerals (K, Mg) was probably also limited. Iron (Fe) was supplemented by soil and foliar spray. B, PD-tolerant scion varieties grafted on PD-tolerant rootstocks, Uvalde. Across rootstocks on 20August, Blanc du Bois was intermediate for growth compared to more vigorous Chambourcin and slower growing Black Spanish (Table 4). Black Spanish had the most mature leaves with nutrient deficiency symptoms. Across scions on 20August, 5BB and 1103P had the most growth, but Florilush uniformly induced Fe deficiency symptoms. Data analysis did not take into account later planting dates for certain plots, especially Black Spanish/Dog Ridge, so growth estimates for that treatments are artificially low. Vine growth was good on this deep high ph soil site. Chambourcin is highly susceptible to powdery mildew (caused by the fungus Erisiphe necator [Uncinula necator]), but Blanc du Bois and Black Spanish are resistant. C, PD-susceptible Sangiovese on selected rootstocks, Leakey. On 18July, the most growth was on 5BB, Dog Ridge, Salt Creek, GRN-1, and 5C rootstocks (Table 5). Own-rooted had the least growth. Percent mature leaves with deficiency symptoms (presumed P deficiency) was least on Dog Ridge and 5C, and greatest on GRN-2, GRN-4, and own-rooted. Fe deficiency symptoms were most frequent on GRN-3, GRN-2, and GRN-1. GRN rootstocks had lower sodium in fall-sampled petioles than other rootstocks (Fig. 1). This experiment did not receive Fe by soil or foliar spray. D, PD-susceptible Sangiovese on selected rootstocks, Stonewall. Freeze losses occurred (Table 6) and in an older test (Table 7). Conclusions: 1. Vines grafted on adapted rootstock(s) are essential for wine grape production in Southwest Texas. 2. Tampa and Florilush rootstocks should not be used in local soils (calcareous high ph).

3. Paulsen 1103 rootstock showed more promise than Kober 5BB and Dog Ridge. Paulsen 1103 has vigor, is tolerant of PD and cotton root rot, is able to take up iron (Fe) in high ph soils, and is available commercially as virus-tested nursery stock. Custom orders for PD-tolerant scions should be planned well in advance. 4. Nutrients in soil and leaf petioles must be monitored in thin/rocky calcareous clay soils of Southwest Texas and supplemented as indicated by laboratory tests and symptoms. Phosphorus deficiency may be an issue in poor calcareous soils in southwest Texas. 5. Fall plantings are at high risk for extensive freeze losses during the first winter. Excess soil moisture in winter increases freeze risk in established plants. Table 2. Observations of powdery mildew and cotton root rot at Leakey and Uvalde, 2011-12. Disease or problem More susceptible Less susceptible Powdery mildew Chardonnay, Merlot, Cabernet Sauvignon, Sangiovese, Chambourcin Blanc du Bois, Black Spanish Cotton root rot Tampa, own-rooted V. vinifera varieties Paulsen 1103 Iron deficiency a Tampa, Florilush Paulsen 1103 a Reduced iron (Fe) uptake in rootstock varieties due to calcareous soil with high ph (8.2 to 8.3). Table 3. Relative vine growth, nutrient deficiency symptoms in mature leaves, and cotton root rot incidence in Pierce s Disease tolerant varieties grafted on selected rootstocks or own-rooted near Leakey (Real County), Texas. Total stem length above cordon, Deficient mature leaves, % b Defoliation Cotton root rot incidence, % c Scion 22Jun f a 20Sep 22Jun 20Sep 5Nov 20Sep 5Nov BlackSpanish 3.7 a 5.7 a d 77 b 90 49 b 5 7 BlancduBois 2.5 b 6.4 a 68 a 91 32 a 6 5? Chambourcin 3.4 a 4.8 b 63 a 92 46 b 9 11 P>F <0.01 0.0013 <0.0001 0.5 N.S. e 0.3 N.S. Rootstock 5BB 4.9 a 8.5 a 74 c 90 ab 37 b 5 ab 6 ab DogRidge 4.8 a 7.3 b 65 b 86 a 24 a 0 a 0 a Own 0.7 b 2.4 c 73 c 98 c 46 c 9 b 10 b 1103P 4.7 a 8.2 ab 53 a 88 ab 43 b c 0 a 0 a Tampa 1.0 b 1.8 c 80 c 92 b 62 d 18 c 23 c P>F <0.0001 <0.0001 <.0001 <.0001 <.0 <.0001 Continued.

Scion * Rootstock Chambourci 1103P 3.5 cd 43 a BlancduBois 1103P 4.0 c 52 ab BlancduBois DgRdg 2.4 de 55 abc Chambourci DgRdg 8.0 a 64 bcd BlackSpanish 1103P 6.6 ab 65 cd BlackSpanish Own 1.3 efg 66 cd Chambourci 5BB 5.2 bc 67 cd Chambourci Own 0.1 g 69 d BlancduBois 5BB 3.8 c 70 d Chambourci Tampa 0.3 fg 71 de BlancduBois Tampa 2.0 def 75 de BlackSpanish 3.9 c 76 de BlackSpanish 5BB 5.8 b 83 ef BlancduBois Own 0.6 fg 85 ef BlackSpanish Tampa 0.8 fg 93 f P>F <0.01 <0.0001 0.0164 <.0001 CV, % 80 64 28 17 51 341 Mean 3.3 5.6 70 91 43 7.4 a Estimates include stems that originated below the cordon wire, and excluded additional branching above the cordon wire. Several vines have been replanted, but julian planting date covariate was not significant for 20September. b Probably P deficiency more than K and Mg deficiencies based on petiole and soil analysis. Several vines have been replanted, and julian planting date as a rootstock covariate on 20September (P>F <0.0001) explained more deficiency symptom variation than all other factors combined. Least squares means reflect an adjustment for planting date. c Caused by the endemic soilborne fungus, Phymatotrichopsis omnivora. d Means followed by the same letter are not different at P=0.05. e Not significantly different at P=0.05.

Table 4. Performance in first leaf of Pierce s disease-tolerant grape varieties on selected rootstocks at Uvalde, Texas in 2012. Relative growth, % Iron deficiency, % leaves Scion 20Aug 27Oct 20Aug 27Oct Pierce s disease % leaves 27Oct Xylella fastidiosa-elisa OD 1Nov Positives, % 1Nov a Powdery mildew % leaves 27Oct Herbicide, % leaves 27Oct b BlackSpanish 78 a c 30 a 24 b 36 2 a 0.128 23 0.2 a 0.05 a BlancduBois 83 b 48 b 16 a 38 1 a 0.083 12 0.1 a 0.02 a Chambourcin 84 b 46 b 20 a 36 4 b 0.151 18 72.2 b 0.52 c P>F d 0.0135 <.0001 0.0019 0.7666 0.0121 0.3143 0.236 <.0001 0.0023 Rootstock DogRidge 81 ab 42 b 1 a 41 b 3 0.122 20 26 b 0.13 a Florilush 78 a 31 a 77 b 76 c 1 0.129 20 18 a 0.00 a 5BB 85 b 46 b 1 a 14 a 3 0.107 16 25 b 0.00 a 1103P 83 b 46 b 1 a 16 a 3 0.125 16 27 b 0.64 b P>F 0.0192 <.0001 <.0001 <.0001 0.1822 0.9790 0.8894 <.0001 0.0010 Scion * Stock BlaSpan DogRdg 75 ab 26 ab 2 a 37 2 0.206 40 c 0 a 0.00 a BlaSpan Florilus 68 a 18 a 90 d 80 0 0.096 20 abc 0 a 0.00 a BlaSpan 5BB 85 bcd 34 bc 2 a 12 1 0.114 20 abc 0 a 0.00 a BlaSpan 1103P 84 bcd 42 cd 3 a 16 3 0.096 13 abc 0 a 0.00 a BlanduB DogRdg 78 b 46 de 1 a 51 0 0.060 07 ab 0 a 0.00 a BlanduB Florilus 84 bcd 39 cd 63 b 71 1 0.209 33 bc 0 a 0.00 a BlanduB 5BB 90 d 62 f 0 a 13 1 0.008 00 a 0 a 0.00 a BlanduB 1103P 80 b 45 de 1 a 16 1 0.054 07 ab 0 a 0.00 a Chambo DogRdg 89 cd 54 ef 1 a 35 5 0.099 13 abc 79 cd 0.07 a Chambo Florilus 82 bcd 37 cd 77 c 77 0 0.081 07 ab 54 b 0.20 a Chambo 5BB 81 bc 40 cd 0 a 15 7 0.200 27 abc 75 c 0.40 a Chambo 1103P 85 bcd 52 e 0 a 16 5 0.225 27 abc 81 d 1.67 b Continued.

P>F 0.001 <.0001 0.0005 0.0917 0.3356 0.0927 0.0373 <.0001 0.0024 CV, % 14 30 61 45 255 207 211 26 440 Mean 82 41 20 36 2 0.121 18 24 0.2 Covariate: DAP e P>F <.0001 estimate 0.58 a Positive if ELISA optical density (OD) 0.300. b Symptoms of phenoxy herbicide drift of unknown origin. c Means (averages) followed by the same letter are not significantly different at P=0.05. d Based on F test, Values of P greater than 0.05 indicate no significant differences. e Delayed planting was necessary for a few plants, but this only had a significant effect on Relative Growth on 20Aug. Later transplants had somewhat less growth on this date (on average, every 0.58 days allowed 1% more growth). SAS Proc GLM estimated LSMeans based on this covariate.

Table 5. Relative Sangiovese vine growth and nutrient deficiency symptoms in mature and immature grape leaves in Expanded Rootstock Experiment near Leakey (Real County), Texas, 18July2012. Rootstock Total stem length above cordon, ft. a Deficient mature leaves, % b Deficient immature leaves, plant incidence c Dog Ridge 10.4 ab 28.0 a 0.00 a Teleki 5C 9.8 abc 32.1 ab 0.02 a Kober 5BB 10.7 a 42.4 bc 0.00 a GRN-1 9.9 abc 47.7 cd 0.21 b Florilush 8.7 bcd 47.7 cd 0.10 a Paulsen 1103 7.8 de 50.0 cd 0.00 a GRN-3 8.5 cd 52.7 cd 0.82 d Salt Creek (Ramsey) 10.1 abc 57.9 de 0.04 a Own rooted 6.2 e 68.5 ef 0.08 a GRN-4 7.6 de 70.9 f 0.02 a GRN-2 7.9 de 73.9 f 0.52 c P>F <.0001 <.0001 <.0001 Replication 1 9.0 44.6 a 0.08 a 3 9.3 45.2 ab 0.27 b 2 8.3 52.9 bc 0.14 a 4 9.2 55.7 cd 0.10 a 5 8.5 61.4 d 0.24 b NS <.0001 <.0001 CV, % 50 57 160 Mean 8.9 52 0.16 a Estimate excluded branching above cordon wire. b Probably P deficiency more than K and Mg deficiencies based on soil and petiole tissue testing. c Probably Fe more than Zn deficiencies based on soil and petiole tissue testing.

Table 6. Relative Sangiovese vine growth 23May12 and survival 6June12 (after freeze & crown gall) of the original transplants (20-21Sep11) in Expanded Rootstock Experiment near Stonewall (Gillespie County), Texas, 23May2012. 23May2012 6June2012 Entry Total stem length above cordon, ft. a Original transplant survival b Original transplant survival GRN-1 4.5 ab 1.8 a 1.8 a Dog Ridge 4.7 a 1.8 ab 1.7 a Florilush 4.6 a 1.6 abc 1.6 ab Teleki 5C 3.6 bcde 1.5 abc 1.2 cd Salt Creek 3.8 abcd 1.5 abc 1.3 bc GRN-4 4.2 abc 1.5 bc 1.2 cd GRN-2 3.5 cde 1.4 cd 1.2 c Kober 5BB 2.8 e 1.3 cd 1.1 cd Paulsen 1103 2.9 de 1.3 cd 1.2 cd GRN-3 2.8 e 1.1 de 0.9 de Sangiovese ownrooted 1.4 f 0.9 e 0.8 e CV 52 48 67 Mean 3.5 1.4 1.3 Pr>F <.0001 <.0001 <.0001 a Estimates excluded branching above cordon wire. b 0 to 2 index, where 0=none of original plants survived, 1=original plants dying, 2=original plants thriving

Table 7. Observations in fourth leaf Vitis vinifera grafted or own rooted near Stonewall, TX, 2012 Scion Growth stage maximum 12Mar12 Pruning weight, g 29Mar12 Log 10 pruning weight 29Mar12 Relative scion growth, % 3Oct12 Freeze and crown gall incidence, % 3Oct12 Dieback from cordon wire 3Oct12 Chardonnay 6.7 c 199 b 2.11 26 a 54 c -2 b Merlot 2.0 b 147 a 1.95 35 b 33 b Non-estimable Cabernet Sauvignon 1.0 a 192 b 2.05 58 c 21 a -1.3 a P>F <.0001 <.0001 0.0625 <.0001 <.0001 0.0426 Stock Dog Ridge 3.0 a 237 b 2.28 b 50 c 16 a Non-estimable Freedom 3.6 b 232 b 2.25 b 41 b 46 b -1.1 a Own rooted 2.9 a 29 a 1.37 a 21 a 66 c -2.2 b Paulsen 1103 3.5 b 218 b 2.24 b 47 bc 17 a -2.6 b P>F 0.0024 <.0001 <.0001 <.0001 <.0001 <.0001 Continued.

Scion * Rootstock Chard/DogRidge 330 d 2.52 e 42 e 23 abc -1.2 ab Chard/Freedom 197 bc 2.13 cd 23 bc 78 e -2.2 c Chard/Own 27 a 1.46 b 8 a 80 e -2.7 c Chard/Pauls1103 241 c 2.33 cde 32 cd 35 cd -2.0 bc Merlot/DogRidge 190 bc 2.23 cd 38 de 1 a Non-estimable Merlot/Freedom 182 b 2.19 cd 40 de 50 d -1.3 b Merlot/Own 8 a 1.16 a 15 ab 78 e -2.5 c Merlot/Pauls1103 207 bc 2.20 cd 46 e 3 a -2.4 c CabSauv/DogRidge 192 bc 2.09 c 71 g 25 bc -0.3 a CabSauv/Freedom 316 d 2.41 de 61 f 9 ab 0.0 a CabSauv/Own 53 a 1.49 b 39 de 39 cd -2.7 c CabSauv/Pauls1103 207 bc 2.19 cd 62 fg 11 ab -2.3 c P>F 0.7101 <.0001 0.0116 0.0424 <.0001 0.0351 P>F Planting Date covariate 0.0198 <.0001 <.0001 0.0349 0.2926 0.4988 CV, % 38 55 24 43 108-45 Mean 3.3 180 2.04 40 36-2

1600 Fig. 1. Sodium in Sangiovese petioles for own-rooted, Paulsen 1103, Kober 5BB, Florilush, GRN-1, GRN-2, GRN-3, GRN-4, Teleki 5C, Salt Creek, and Dog Ridge, sampled in late fall 2012 and composited over five replications, at Leakey, TX 1400 1200 Sodium (Na) PPM 1000 800 600 400 200 0 SV 3P 5B FL G1 G2 G3 G4 5C SC DR Grape Rootstock