Table 1.
Information of partial sequences D2-D3 of ribosomal DNA downloaded from GenBank and obtained in the present study for Bursaphelenchus.
| Isolate | Species name | Location | Plant-host | Insect host | GenBank accession number | Reference or source |
|---|---|---|---|---|---|---|
| 1 | B. cocophilus | Tibu, Norte de Santander, Colombia | Elaeis guineensis | R. palmarum | MN612640 | Present study |
| 2 | B. cocophilus | Tibu, Norte de Santander, Colombia | Elaeis guineensis | R. palmarum | MN612641 | Present study |
| 3 | B. cocophilus | Tibu, Norte de Santander, Colombia | Elaeis guineensis | R. palmarum | MN612642 | Present study |
| 4 | B. cocophilus | Tibu, Norte de Santander, Colombia | Elaeis guineensis | R. palmarum | MN612643 | Present study |
| 136 | B. abruptus | USA | None | Anthophora abrupta | AY508073 | Ye et al. (2007) |
| 137 | B. abietinus | Austria | Pityokteines vorontzowi | Abies alba | AY508074 | Ye et al. (2007) |
| 170 | B. anatolius | Turkey | Halictus sp. | None | AY508093 | Ye et al. (2007) |
| S12 | B. cocophilus | Brazil | Cocos nucifera | R. palmarum | KT156772 | Silva et al. (2016) |
| NT25 | B. cocophilus | Colombia | Cocos nucifera | R. palmarum | KT156775 | Silva et al. (2016) |
| NT26 | B. cocophilus | Colombia | Cocos nucifera | R. palmarum | KT156776 | Silva et al. (2016) |
| 153 | B. fungivorus | Germany | Greenhouse soil | Unknown | AY508082 | Ye et al. (2007) |
| 154 | B. hellenicus | Greece | Tomicus piniperda | Pinus brutia | AY508083 | Ye et al. (2007) |
| 168 | B. mucronatus | Germany | Picea abies | Monochamus galloprovincialis | AY508091 | Ye et al. (2007) |
| 173 | B. poligraphi | Germany | Picea abies | Polygraphus poligraphus | AY508096 | Ye et al. (2007) |
| 171 | B. platzeri | USA | None | Carpohilus humeralis | AY508094 | Ye et al. (2007) |
| 174 | B. seani | USA | None | Anthophora bomboides | AY508097 | Ye et al. (2007) |
| 176 | B. seani | USA | None | Anthophora bomboides | AY508099 | Ye et al. (2007) |
| 180 | B. sexdentati | Italy | Pinus pinaster | Unknow | AY508103 | Ye et al. (2007) |
| 1057 J | B. taphrorychi | Poland | Fagus sylvatica | Taphrorychus bicolor | MF422699 | Tomalak et al. (2017) |
| 98 | Aphelenchoides besseyi | USA | Fragaria ananassa | – | AY508109 | Ye et al. (2007) |
Figure 1:
Foliar symptoms caused by Bursaphelenchus cocophilus, causal agent of red ring disease on oil palm. A: General aspect of diseased oil palm and some chlorosis on upper leaves. B: Thin leaflets and leaf chlorosis of the upper third. C: Shortening of young leaves. D-F: Progressive collapse of chlorotic leaves and leaf rotting.
Figure 2:
Symptoms caused by Bursaphelenchus cocophilus, the red ring nematode, in oil palm production in Colombia. A: Final piece of stem tissue from symptomatic and advance zone of the lesion. B: Small necrotic dots that form a discontinuous ring. C, D: Continuous necrotic area forming a ring of reddish brown color. E-G: Symptoms at the base of petioles of leaves.
Table 2.
Average number of nematodes (Bursaphelenchus cocophilus) in five grams of fresh tissue from different plant organs according to extraction and sampling method.
| Extraction method (Decantation) | Sampling method | |||
|---|---|---|---|---|
| Tissue class | With facial paper | Without facial paper | Palms knocked down | Palms standing (Drill) |
| Peduncle | 10 | 8 | X | |
| Petiolar Base | 16 | 501 | X | |
| Spear leaf base | 5 | 0 | X | |
| Inflorescences | 110 | – | X | |
| Stem | 469 | 51 | X | |
| Stem | 1 |
|
| |
Table 3.
Population of Bursaphelenchus cocophilus according to sampling and extraction method.
| Extraction method (Decantation) | Sampling method | |||
|---|---|---|---|---|
| With facial paper | Without facial paper | Palms knocked down | Palms standing (Drill) | |
| Maximum Population | 1,295 | 720 | X | |
| Maximum population | 2 | 5 | X | |
| Absolute density | 150 | 150 | X | |
| Absolute density | 0.86 | 4 | X | |
| Absolute frequency | 58.8 | 71.4 | X | |
| Absolute frequency | 42.9 | 85.7 | X | |
Figure 3:
Microphotographs Bursaphelenchus cocophilus. A, B: Previous segment observed estomatostilet and male tail detail. Scale bar = 20 µm. C: Long slim male of Bursaphelenchus cocophilus. Scale bar = 100 µm.
Table 4.
Morphometric data of males of a B. cocophilus population characterized in the present study and others of reference populations
| Locality/Publication | Tibu-North Santander, Colombia oil palm (Present study) n=12 | Brazil Coconut Red Ring Disease After (Lordello and Zamith, 1954) n=5 | Trinidad coconut Red Ring Disease (Basil, 1960) n=10 | Venezuela oil palm Red Ring Disease (Gerber et al., 1989) n=10 | Venezuela oil palm Little leaf (Gerber et al., 1989) n=10 |
|---|---|---|---|---|---|
| Body length | 964.67±70.07 (807.09-1062.67) | 820-1420 | 1020 (840-1160) | 1017±77 (841-1111) | 866±71 (789-965) |
| a | 83.89±10.68 (69.53-99.78) | 92-143 | 120 (100-179) | 129.7±13.3 (113.8-150.0) | 99.3±11.8 (78.9-116.1) |
| c | 29.33±1.72 (27.02-32.25) | 22-47 | 28 (24-35) | 26.1±2.2 (22.5-29.2) | 22.4±2.8 (18.8-26.5) |
| c′ | 3.70±0.31 (3.19-4.31) | – | – | 5.6±0.5 (4.8-6.4) | 5.4±0.8 (4.7-6.8) |
| T | 96.58±0.20 (96.30-96.90) | – | – | – | – |
| Max. Body diam. | 11.62±1.34 (9.97-14.22) | – | – | 8±1.0 (7.0-9.0) | 9.0±1.0 (7.0-10.0) |
| Stylet | 10.90±0.88 (9.07-12.12) | 10.7-13.8 | 12-13 | 11±1.0 (11-12) | 12.0±1.0 (11.0-12.0) |
| Lip region width | 4.61±0.52 (3.81-5.22) | – | 5.5 | – | – |
| Lip region height | 3.13±0.43 (2.43-365) | – | 3.0 | – | – |
| Median bulb length | 12.16±0.79 (10.75-13.04) | – | – | – | – |
| Median bulb diam. | 5.99±0.84 (4.66-7.64) | – | – | – | – |
| Tail length | 32.83±2.35 (28.94-37.90) | – | – | 39.0±4.0 (32.0-46.0) | 39.0±4.0 (33.0-46.0) |
| Cloacal or anal body diam. | 8.90±0.71 (7.75-10.16) | – | – | 7.0±1.0 (5.0-8.0) | 7.0±1.0 (6.0-9.0) |
| Spicule length | 15.21±1.41 (13.29-17.32) | – | – | 12.0±1.0 (11.0-13.0) | 11±1.0 (10.0-13.0) |
Figure 4:
Phylogenetic tree obtained by the statistical method of maximum likelihood based on the general time reversible (GTR) model of the consensus sequences of the D2-D3 partial segment of some species of the genus Bursaphelechus. The sequences of this work are indicated in bold. The numbers on the nodes indicate bootstrap values >70%. The species Aphelenchoides besseyi (AY508109.1) is included as outgroup.