Issue link: http://winesandvines.uberflip.com/i/918844
124 WINES&VINES January 2018 GRAPEGROWING PRACTICAL WINERY & VINEYARD disease rating of 3 or 4 and an acetic acid content of at least 0.83 g/L (based on the ranges detected in field samples). Across all three cultivars, the only combinations of organisms that caused sour rot per our cri- teria were: • Aspergillus niger (filamentous fungus) x Gluconobacter oxy- dans (AAB) • Hanseniaspora uvarum (yeast) x Acetobacter aceti (AAB) • Hanseniaspora uvarum x Acetobacter aceti x Gluconobacter oxydans • Pichia kluyveri (yeast) x Acetobacter aceti • Pichia kluyveri x Gluconobacter oxydans • Saccharomyces cerevisiae (yeast) x Acetobacter aceti • Saccharomyces cerevisiae x Gluconobacter oxydans However, these combinations produced sour rot symptoms only on berries also exposed to wild type Drosophila fruit flies, which carry their own microbi- ota. When inoculated berries were not exposed to the flies, typical sour rot symptoms did not develop. CONTROL OF SOUR ROT WITH ANTI-MICROBIAL SPRAYS +/- INSECTICIDE Mean percent disease control over the untreated check in each year and the mean percent control across all years in which that treatment was administered Antimicrobial treatment, rate and timing a Insecticide b 2013 2015 2016 Mean None No 0% 0% 0% 0% Yes 9% 57% 40% 35% KMS, 0.5% pre-symptom No 11% 11% Yes 30% 30% KMS, 1% pre-symptom No 12% 0% 11% 8% Yes 52% 76% 66% 65% KMS, 1% post-symptom No 8% 34% 21% Yes 46% 46% 46% Kocide 3000, 1.75 pounds/ acre pre-symptom No 10% 10% Yes 54% 54% Fracture, 32 fluid ounces per acre pre-symptom No 14% 32% 23% Yes 73% 52% 63% Fracture, 32 fluid ounces per acre at 15° Brix No 12% 12% Yes 58% 58% Fracture, 32 fluid ounces per acre post-symptom No 32% 15% 23% Yes 56% 44% 50% Oxidate 2.0, 1% pre-symptom No 31% 3% 17% Yes 84% 55% 69% Oxidate 2.0, 1% post-symptom No 36% 0% 18% Yes 40% 53% 47% Oxidate 2.0, 1% weekly following first rain after 15° Brix No 27% 27% Yes 33% 33% Oxidate 2.0, 1% weekly following increase in maximum daily dew point over three consecutive days No 47% 47% Yes 33% 33% a Unless otherwise noted, antimicrobial treatments were applied weekly upon initiation. Pre-symptom treatments started at 15.0° Brix, and post-symptom treatments after sour rot symptoms were first detected in the vineyard. b Insecticide sprays (Delegate [spinetoram] in 2013, Mustang Maxx [zeta- cypermethrin] in 2015 and 2016) were applied to designated rows at label rates weekly beginning at 15.0° Brix. CustomDrains.com 888-487-3444 • Area Stainless Drains • Open Trench Drains • Narrow Slot Trench Drains • Cleanouts – P-Traps YOUR GATEWAY TO TEXAS Texas Wine and Grape Growers Association 2018 Annual Conference and Trade Show www.txwines.org/2018-conference-trade-show/ February 22–24, 2018 Irving Convention Center 500 West Las Colinas Blvd. Irving, TX • 3 days and over 30 hours of Educational Sessions • 156 Trade Show Booths • 13 Exhibit Hall Hours • Networking with Texas wineries and growers • Texas size wine tastings Contact office@twgga.org or 817-421-3201