Table 1.
Number of plant-parasitic nematodes of six different genera counted in nematode extract from 100cc of soil from 12 sugarcane plantation sites at Tanganyika Planting Company Limited in Kilimanjaro region of Tanzania in July, 2017.
| Collection sites | GPS coordinates | Rotylenchulus | Pratylenchus | Tylenchorhynchus | Scutellonema | Hemicycliophora | Helicotylenchus |
|---|---|---|---|---|---|---|---|
| N50-North | 3° 25´ 1.20˝ S, 37° 18´ 49.68˝ E | 33 | 18 | 0 | 5 | 0 | 0 |
| N54-North | 3° 25´ 20.32˝ S, 37° 18´ 49.68˝ E | 117 | 6 | 3 | 0 | 0 | 1 |
| N84-North | 3° 23´ 58.34˝ S, 37° 20´ 1.43˝ E | 14 | 13 | 0 | 0 | 0 | 0 |
| D8-East | 3° 28´ 1.38˝ S, 37° 20´ 15.04˝ E | 7 | 11 | 0 | 0 | 0 | 0 |
| D30-East | 3° 30´ 11.12˝ S, 37° 20´ 56.86˝ E | 21 | 11 | 0 | 0 | 0 | 0 |
| C6-East | 3° 28´ 2.25˝ S, 37° 19´ 33.68˝ E | 12 | 2 | 0 | 0 | 5 | 1 |
| D20-East | 3° 29´ 1.62˝ S, 37° 20´ 42.02˝ E | 12 | 20 | 1 | 1 | 7 | 1 |
| E11-East | 3° 28´ 58.72˝ S, 37° 21´ 0.07˝ E | 22 | 84 | 1 | 0 | 0 | 0 |
| F13-South | 3° 33´ 44.52˝ S, 37° 18´ 51.03˝ E | 1037 | 11 | 5 | 0 | 0 | 0 |
| F10-South | 3° 31´ 9.67˝ S, 37° 20´ 15.71´ E | 170 | 0 | 16 | 0 | 1 | 0 |
| 11E-South | 3° 28´ 28.45˝ S, 37° 20´ 44.26˝ E | 7 | 15 | 1 | 0 | 0 | 0 |
| R7S-South | 3° 29´ 48.49˝ S, 37° 18´ 10.96˝ E | 47 | 10 | 0 | 0 | 0 | 0 |
Figure 1:
The above-ground view of sugarcane showing stunted growth and yellowing of leaves on the field site F13-South of Tanganyika Planting Company Limited in Kilimanjaro. Soil sample analysis from this field revealed the presence of more than 1,000 immature females and males of Rotylenchulus parvus in 100cc of soil.
Table 2.
Morphometrics of immature females and males of Rotylenchulus parvus collected from F13-South of Tanganyika Planting Company Limited in Kilimanjaro region of Tanzania.
| Character | Immature females | Males |
|---|---|---|
| n | 28 | 5 |
| L | 327 ± 29 (271-352) | 393 ± 38 (342-426) |
| a | 24.9 ± 1.6 (21.9-26.8) | 31.1 ± 1.6 (29.4-33.2) |
| b | 3.2 ± 0.5 (2.6-3.9) | 3.7 ± 0.2 (3.5-3.9) |
| c | 15.3 ± 0.4 (12.3-17.5) | 17.0 ± 0.9 (16.0-18.1) |
| DGO | 17.3 ± 1.1 (16.6-18.0) | – |
| V | 62% (60%-66%) | – |
| Stylet length | 14.5 ± 0.4 (13.1-15.4) | 11.9 ± 0.3 (11.7-12.3) |
| Metenchium length | 6.4 ± 0.3 (6.0-6.5) | 5.2 ± 0.1 (5.2-5.3) |
| Telenchium length | 8.1 ± 0.2 (6.3-8.7) | 6.6 ± 0.2 (6.4-6.9) |
| Stylet knob width | 2.7 ± 0.3 (2.5-2.9) | 1.5 ± 0.2 (1.4-1.6) |
| Stylet knob height | 1.6 ± 0.3 (1.4-1.8) | 0.9 ± 0.1 (0.9-1.0) |
| Pharyngeal length | 102 ± 8.7 (97.9-110) | 109 ± 1.1 (108-110) |
| SE pore from anterior end | 75.4 ± 3.2 (74.0-77.0) | 77.9 ± 0.6 (77.5-78.5) |
| Mid-body diameter | 12.7 ± 1.6 (12.7-13.4) | 12.6 ± 1.1 (11.2-13.8) |
| Median bulb length | 9.1 ± 0.8 (8.6-9.8) | 8.0 ± 0.9 (7.4-8.6) |
| Median bulb diameter | 7.0 ± 0.2 (6.9-7.6) | 5.1 ± 0.3 (4.9-5.3) |
| Lip region diameter | 3.8 ± 0.8 (3.1-4.2) | 3.5 ± 0.2 (3.4-3.5) |
| Lip region height | 2.4 ± 0.3 (2.2-2.6) | 2.1 ± 0.5 (1.6-2.7) |
| Tail | 21.4 ± 0.8 (18.5-25.3) | 23.1 ± 2.0 (20.3-25.0) |
| Hyaline tail (h) | 2.5 ± 0.4 (1.3-3.1) | 3.4 ± 0.5 (2.9-3.9) |
| Spicule length | – | 16.7 ± 1.2 (16.0-17.5) |
| Gubernaculum length | – | 5.6 ± 0.5 (5.0-6.0) |
Table 3.
Comparison of important morphological characters and morphometrics of immature females of the Tanzanian Rotylenchulus parvus found from sugarcane field F13-South of Tanganyika Planting Company Limited in Kilimanjaro region of Tanzania, with seven other Rotylenchulus spp. and the original measurements of R. parvus from Mauritius and from South Africa.
| Character | R. clavicaudatus from South Africa after Van den Berg et al. (2016) | R. leptus from South Africa after Van den Berg et al. (2016) | R. macrodoratus from Italy after Van den Berg et al. (2016) | R. macrosoma from Spain after Castillo et al. (2003a) | R. macrosomoides from South Africa after Van den Berg et al. (2016) | R. parvus (=Helicotylenchus parvus) from Mauritius after Williams (1960a, b) | R. parvus from South Africa after Van den Berg (1978) | R. parvus from Kilimanjaro, Tanzania (2017) | R. reniformis after Agudelo et al. (2005) | R. sacchari from South Africa after Van den Berg et al. (2016) |
|---|---|---|---|---|---|---|---|---|---|---|
| n | 11 | 14 | 9 | 12 | 10 | 6 | 198 | 28 | 20 | 25 |
| Body length | 483-624 | 321-434 | 407-489 | 408-510 | 463-590 | 210-270 | 231-432 | 271-352 | 340-560 | 574-796 |
| a | 27.6-36.9 | 25.7-29.9 | 22.6-27.4 | 26.3-34.2 | 31.4-37.3 | 19.0-24.0 | 15.3-32.3 | 21.9-26.8 | 20.3-31.9 | 28.8-36.9 |
| b | 3.8-4.7 | 2.9-4.3 | 2.9-4.0 | 3.5-4.4 | 3.8-4.7 | 2.9-3.3 | 2.0-4.4 | 2.6-3.9 | 2.3-4.1 | 3.1-5.0 |
| c | 9.1-11.8 | 14.5-17.3 | 18.5-22.2 | 11.7-16.8 | 14.1-21.4 | 16.0-20.0 | 13.1-27.1 | 12.3-17.5 | 10.0-22.8 | 26.1-43.0 |
| DGO | 11.0-18.0 | 20.0-24.5 | 13.0-18.0 | 22.0-27.0 | 30.0-33.0 | – | 7.7-17.3 | 16.6-18.0 | – | 8.0-15.5 |
| V% | 55-61 | 59-65 | 62-67 | 59-64 | 76-83 | 61-65 | 56-69 | 60-66 | 66-73 | 62-71 |
| Stylet length | 16.0-20.0 | 12.5-14.5 | 21.0-24.0 | 15.0-18.0 | 21.5-25.5 | ca 12.5 | 10.7-19.9 | 13.1-15.4 | 16.0-22.0 | 26.5-34.5 |
| Tail length | 43.0-66.0 | 20.0-28.0 | 20.0-24.0 | 26.0-40 | 26.5-36.0 | – | 10.5-27.2 | 18.5-25.3 | – | 15.5-28.0 |
| Hyaline length | 19.0-35.5 | 1.4-4.0 | 8.0-12.0 | 9.0-12.0 | 17.0-25.5 | – | 0.8-5.2 | 1.3-3.1 | 4.0-9.0 | 4.5-10.5 |
| Tail shape and structure | Broadly rounded, clavate, annulated tip | Tapering gradually to a finely rounded annulated tip | Bluntly rounded and slightly annulated terminus | Bluntly rounded and prominently annulated terminus | Tapering to a rounded or slightly clavate annulated tip | Arcuate, conoid, terminus knob like, length twice anal body diameter | Conoid, ventrally arcuate with sharply pointed or irregular or broadly rounded tip | Conoid, tapering to rounded tip | Tapering to rounded terminus | Broadly rounded, faint annulation at the tip |
| Habitus | Open letter C to complete circle | Open Figure 6 to 1.5 circle | Closed C-shape | Closed C-shape | C to curved into 1.5 circles | Loose spiral resembling 6-shape | C- or 6-shape or complete circle | C- to 6-shape | Open spiral to C-shape | Almost straight to C-shape rarely 1.5 circles |
| Labial region | Slightly sloping anteriorly to a slightly rounded tip, not set off | Sloping to a flattened tip | Conoid rounded, not set off | Conoid rounded, not set off | High, sloping slightly to a slightly flat or rounded tip | Continuous with neck, sloping to a rounded, distinctly flattened front | Broadly rounded, almost flat, not set off | Low, not set off and flattened front | High, conoid and continuous | Slightly sloping to flattened tip |
| Labial annuli | Not present | 4 to 5 | Fine annuli | Fine annuli | Not visible | – | 3-5 faint annuli | 4 to 5 faint annuli | 4 to 6 | 5 to 6 faint annuli |
Figure 2:
Light microscopy images of Rotylenchulus parvus found in the field site F13-South of Tanganyika Planting Company Limited in Kilimanjaro. A-B: Anterior regions of immature females, C: Lateral field showing four distinct incisures, D-E: Female body showing vulval position, F-I: Female tail region showing tail hyaline part, J-K: Anterior and posterior regions of male, respectively, L-M: Whole body of male and juvenile, respectively, N: Tail of juvenile with a rounded tail tip.
Figure 3:
Light microscopy images of three plant parasitic nematode species detected in this study. A-F: Pratylenchus zeae, G-M: Tylenchorhynchus crassicaudatus, and N-T: Tylenchorhynchus ventrosignatus.
Figure 4:
Phylogenetic relationships of Rotylenchulus parvus from Tanzania with seven other Rotylenchulus species. Bayesian 50% majority rule consensus tree as inferred from the analysis of ITS of rDNA sequences under GTR + I + G model. Posterior probabilities of more than 0.5 are given for appropriate clades.
Figure 5:
Phylogenetic relationships of the Tanzanian Rotylenchulus parvus with eight known and four unknown Rotylenchulus species. Bayesian 50% majority rule consensus tree as inferred from the analysis of D2-D3 of 28S rDNA sequences under GTR + I + G model. Posterior probabilities of more than 0.5 are given for appropriate clades.
Figure 6:
Phylogenetic relationships of Rotylenchulus parvus from Tanzania with six known and six unknown Rotylenchulus species. Bayesian 50% majority rule consensus tree as inferred from the analysis of COI of mtDNA sequences under GTR + I + G model. Posterior probabilities more than 0.5 are given for appropriate clades.
Table 4.
Comparison of important morphological characters and morphometrics of the Tanzanian Tylenchorhynchus crassicaudatus, found from sugarcane field F10-South of Tanganyika Planting Company Limited in Kilimanjaro region of Tanzania, with the original measurements of T. crassicaudatus from Mauritius and T. agri from the USA along with three other populations of T. agri and T. crassicaudatus from Niger, USA and Haiti.
| Character | T. crassicaudatus from cane roots in Mauritius (Williams, 1960a, b) | T. agri from corn field in Urbana, Illinois, USA (Ferris, 1963) | T. crassicaudatus from Niger (2011) | T. agri from dwarf date palm in Lake Worth, Florida, USA (Handoo et al., 2014) | T. crassicaudatus from sugarcane field in Kilimanjaro, Tanzania (2017) | T. agri from rice field in Haiti (2018) |
|---|---|---|---|---|---|---|
| n | 5 | 10 | 6 | 1 | 5 | 10 |
| Body length | 580-690 | 660-770 | 521-666 | 662 | 725-755 | 538-695 |
| a | 28-33 | 28-33 | 27-31 | 32.9 | 28-35 | 23-32 |
| b | 4.9-5.7 | 4.7-5.5 | 4.3-5.0 | 4.9 | 4.7-5.2 | 4.4-5.3 |
| c | 14-15 | 15-21 | 13-16 | 13.3 | 14-17 | 12-15 |
| V% | 53-57 | 55-58 | 53-59 | 55.1 | 53-55 | 51-55 |
| Stylet length | ca 20 | 20-23 | 18-20 | 21 | 19-20 | 18-19 |
| Tail length | ca 50 | – | 37-42 | 50 | 43-56 | 43-53 |
| Tail annuli number | 17-19 | 18-26 | 17-23 | 25 | 21-26 | 18-20 |
| Tail shape | Straight to slightly arcuate, thick and clavate | Subcylindrical | Clavate to subcylindrical | Subcylindrical | Subcylindrical | Subcylindrical |
| Tail terminus | Smooth, rounded and virtually hemispherical | Broadly rounded and smooth | Smooth, rounded and virtually hemispherical | Smooth and broadly rounded | Smooth and rounded | Broadly rounded and smooth |
| Post anal intestinal sac | Not mentioned (absent?) | Present | Absent | Not mentioned | Not present | Present or absent |
| Labial region | Broadly rounded, low, not setoff | Separated from body contour by slight depression | Broadly rounded, low, not set off, sometimes seems separated from body contour by slight depression | Continuous with body contour or separated by slight depression | Broadly rounded, not set off, sometimes seems separated from body contour by slight depression | Seems separated from body contour by slight depression |
| Labial annuli | 3 | 3 + labail disc | 3 | 3 to 4 | 3 | 3 |
Figure 7:
Phylogenetic relationships of Tylenchorhynchus crassicaudatus and Tylenchorhynchus ventrosignatus from Tanzania with other Tylenchorhynchus species. Bayesian 50% majority rule consensus tree was inferred from the analysis of D2-D3 of 28S rDNA sequences under GTR + G model. Posterior probabilities more than 0.5 are given for appropriate clades.