Table 3.
Impact of grapevine leafroll disease on yield and fruit composition of V. vinifera cv. Pinot noir on rootstock 5BB over three consecutive years. Means within year followed by different letters differ significantly at p < 0.05 by Ducan’s new multiple range test. GLD_S+: Grapevine leafroll disease causing mild symptoms; GLD_S++: grapevine leafroll disease causing severe symptoms. Total (titratable) acidity is expressed in g/L of tartaric acid. YAN: yeast assimilable nitrogen (mg/L); n.a.: data not taken.
| Yield (kg/vine) | Soluble Solids (°Brix) | pH | Total Acidity | Tartaric Acid (g/L) | YAN | |
|---|---|---|---|---|---|---|
| 2015 | ||||||
| Symptomless | 0.6 a | 22.2 a | 3.12 a | 8.6 a | 7.9 a | 178 a |
| GLD_S+ | 0.5 a | 22.5 a | 3.10 a | 8.3 a | 7.5 a | 132 a |
| GLD_S++ | 0.1 b | 22.4 a | 3.33 b | 6.8 b | 6.4 b | 65 b |
| 2016 | ||||||
| Symptomless | 1.0 a | 24.1 a | 3.23 a | 8.0 a | 6.4 a | 151 a |
| GLD_S+ | 1.1 a | 23.3 a | 3.12 b | 8.4 a | 6.7 a | 111 ab |
| GLD_S++ | 0.2 b | 19.4 b | 3.25 a | 7.8 a | 6.1 a | 66 b |
| 2017 | ||||||
| Symptomless | 0.6 a | 22.5 a | 3.23 a | 8.7 a | 6.5 a | 245 a |
| GLD_S+ | 0.3 b | 22.4 a | 3.23 a | 8.8 a | 6.5 a | 178 b |
| GLD_S++ | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. |