Table 1.
Biocontrol of Verticillium wilt of cauliflower by V. isaacii Vt305 in field conditions at three locations (Ardooie and Bornem in 2014 and Oppuurs in 2015). Cauliflower seeds (cv Clapton, Korlanu or Clarina) were treated with water (control) or a microsclerotia (MS) suspension of V. isaacii Vt305 at different concentrations: 300 MS, 500 MS, or 1000 MS per seed. At harvest (76 dpt in Ardooie, 73 dpt in Bornem and 66 dpt in Oppuurs), vascular discoloration of the stems was scored: 0 = no vascular discoloration; 1 = vascular discoloration of <50% of stem length; 2 = vascular discoloration of 50–75% of stem length; and 3 = vascular discoloration of 76–100% of stem length. For each location the percentage of plants with a specific score for vascular discoloration (mean of 4 plots ± standard error), the disease index (%) (mean of 4 plots ± standard error) and the percentage of marketable cauliflower curds are shown.
| Cultivar | % Plants | % Plants | % Plants | % Plants | Disease | Marketable | |
|---|---|---|---|---|---|---|---|
| Score 0 | Score 1 | Score 2 | Score 3 | Index (%) 1 | Curds (%) | ||
| Ardooie | |||||||
| Control | Clapton | 4.4 ± 2.2 a 2 | 22.2 ± 2.2 a | 48.9 ± 4.4 a | 24.5 ± 2.2 a | 64.4 ± 2.2 a | 75.5 ± 2.2 a |
| 300 MS | Clapton | 17.8 ± 8.0 b | 37.8 ± 4.5 ab | 33.3 ± 11.5 a | 11.1 ± 4.4 ab | 45.9 ± 7.4 b | 88.9 ± 4.4 b |
| 500 MS | Clapton | 11.1 ± 2.2 ab | 42.2 ± 5.9 b | 46.7 ± 7.7 a | 0.0 ± 0.0 c | 45.2 ± 3.2 b | 100.0 ± 0.0 c |
| 1000 MS | Clapton | 13.3 ± 3.8 ab | 48.9 ± 8.9 b | 35.6 ± 4.4 a | 2.2 ± 2.2 bc | 42.2 ± 2.2 b | 97.8 ± 2.2 c |
| Bornem | |||||||
| Control | Korlanu | 48.0 ± 10.6 a | 45.0 ± 8.5 a | 7.0 ± 2.5 a | 0.0 ± 0.0 a | 19.7 ± 4.3 a | 100.0 ± 0.0 a |
| 300 MS | Korlanu | 50.0 ± 10.4 a | 45.0 ± 5.7 a | 5.0 ± 5.0 ab | 0.0 ± 0.0 a | 18.3 ± 5.1 a | 100.0 ± 0.0 a |
| 500 MS | Korlanu | 72.0 ± 6.9 b | 27.0 ± 6.0 b | 1.0 ± 1.0 b | 0.0 ± 0.0 a | 9.7 ± 2.6 a | 100.0 ± 0.0 a |
| 1000 MS | Korlanu | 57.0 ± 27.0 a | 40.0 ± 12.0 ab | 3.0 ± 1.9 ab | 0.0 ± 0.0 a | 15.3 ± 5.0 a | 100.0 ± 0.0 a |
| Oppuurs | |||||||
| Control | Korlanu | 10.7 ± 6.3 ab | 39.3 ± 8.1 a | 36.9 ± 7.1 a | 13.1 ± 4.9 a | 50.8 ± 3.7 a | 86.9 ± 4.9 a |
| 500 MS | Korlanu | 9.6 ± 5.1 a | 57.1 ± 3.9 b | 21.4 ± 5.0 b | 11.9 ± 7.1 a | 45.2 ± 6.0 ab | 88.1 ± 7.1 a |
| Control | Clarina | 15.5 ± 9.0 ab | 48.8 ± 3.0 ab | 35.7 ± 10.4 a | 0.0 ± 0.0 b | 40.1 ± 6.4 b | 100.0 ± 0.0 b |
| 500 MS | Clarina | 21.4 ± 12.4 b | 60.7 ± 7.6 b | 15.5 ± 4.1 b | 2.4 ± 1.4 b | 32.9 ± 6.2 c | 97.6 ± 1.4 b |
1 The disease index was calculated based on the scores for vascular discoloration via the formula of Townsend-Heuberger [(0*a + 1*b + 2*c + 3*d)/(e*f)]*100; letters a, b, c, and d, are the numbers of plants for each disease score, the letter e is the highest score (=3), and f represent the number of observations (= 20). 2 For each location, values with the same letter within the same column do not differ significantly according to the Mann-Whitney U-test (p < 0.05).