Figure 1.
Samples of U. glabra wood with typical browning of infected tissues: sample 1 (A) and sample 2 (B)
Figure 2.
General appearance of old U. glabra trees: accounting tree No 1 (A) and accounting tree No 3 (B)
Table 1.
Characteristics of the health condition of old U. glabra trees and causes of their weakening
| Numbers of trees | Forest measurement parameters | Category of health condition | Defoliation, points | Epicormic shoots and vegetative buds, points | Causes of weakening | |
|---|---|---|---|---|---|---|
| diameter, cm | height, m | |||||
| 1 | 52 | 30 | I | 0 | 0 | – |
| 2 | 52 | 29 | III | 2 | 2 | Bacterial wetwood |
| 3 | 32 | 27 | I | 0 | 0 | – |
| 4 | 40 | 28 | II | 1 | 1 | Dieback |
| 5 | 90 | 32 | II | 2 | 2 | Bacterial wetwood |
| 6 | 24 | 20 | I | 1 | 0 | – |
| 7 | 28 | 22 | I | 0 | 0 | – |
| 8 | 24 | 18 | II | 1 | 1 | Leaf deformation, brown leaf spot |
| 9 | 28 | 20 | I | 0 | 0 | – |
| 10 | 48 | 28 | I | 1 | 0 | – |
| 11 | 86 | 33 | III | 2 | 3 | Bacterial wetwood, Cerioporus squamosus |
| 12 | 56 | 30 | I | 0 | 0 | – |
| 13 | 36 | 28 | II | 1 | 1 | Leaf deformation |
| 14 | 68 | 32 | II | 1 | 1 | Cerioporus squamosus |
| 15 | 56 | 31 | I | 0 | 0 | – |
Figure 3.
Macro signs in the trunk of U. glabra infected with bacterial wetwood: A – leakage of bacterial exudate, B – longitudinal ulcers in the lower part of the trunk, C – mass formation of ‘witches’ brooms’
Table 2.
Characterisation of bacteria isolated from U. glabra wood samples against collection strain and identifier
| Tests | Tested bacteria | Lelliottia nimipressuralis | |
|---|---|---|---|
| collection strain 8791 | Bergey, 2005 | ||
| Gram stain | − | − | − |
| Bacterial motility | + | + | + |
| Yellow pigment | − | − | − |
| Oxidase | − | − | − |
| Nitrate reduction | + | + | + |
| Protopectinase | − | − | − |
| Use of glucose (anaerobic) | + | + | + |
Figure 4.
Anaerobic growth of bacterial isolates from samples of infected U. glabra wood on Omelyansky medium with glucose (B1a, B2, B5, B6, B6a, B9 – conventional designations of bacterial isolates isolated from elm sample; 8791 – conventional designation of the collection strain)
Table 3.
Properties of phytopathogenic bacteria isolated from U. glabra wood samples on API 20E strips
| Tests | Reaction/enzyme | Tested bacteria | Collection strain Lelliottia nimipressuralis 8791 |
|---|---|---|---|
| 1 | 2 | 3 | 4 |
| ONPG | β-galactosidase | + | + |
| ADH | arginine dihydrolase | − | − |
| LDC | lysine decarboxylase | − | − |
| ODC | ornithine decarboxylase | + | + |
| CIT | use of citrate | + | + |
| H2S | hydrogen sulphide production | − | − |
| URE | urease enzyme test | − | − |
| TDA | tryptophan deaminase | − | − |
| IND | indole test | − | − |
| VP | voges–proskauer test | + | + |
| GEL | gelatinase | − | − |
| GLU | glucose fermentation | + | + |
| MAN | fermentation of mannose | + | + |
| INO | fermentation of inositol | − | − |
| SOR | fermentation of sorbitol | − | − |
| SAC | fermentation of sucrose | + | + |
| MEL | fermentation of melibiose | + | + |
| AMY | fermentation of amygdalin | + | + |
| ARA | fermentation of arabinose | + | + |