Table 1
Collection data for specimens used in this study. Specimens 1 to 15 were examined as fixed specimens.
| Specimen ID | Species | Locality | Host | Marker | GenBank Accession No. |
|---|---|---|---|---|---|
| 1 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 2 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 3 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 4 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 5 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 6 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 7 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 8 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 9 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 10 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 11 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 12 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 13 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 14 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| 15 | H. medicaginis | Kearny County, Kansas | Alfalfa | N/A | |
| P169028 | H. medicaginis | Kearny County, Kansas | Alfalfa | 18S | AY912048 |
| N838 | H. schachtii | Goshen County, Wyoming | Soybean | COI | MK093062 |
| N839 | H. schachtii | Goshen County, Wyoming | Soybean | COI | MK093063 |
| N864 | H. schachtii | Goshen County, Wyoming | Soybean | COI | MK093064 |
| N4143 | Meloidodera sp. | Big Thicket National Preserve, Texas | Beech | COI | MK093163 |
| N4178 | Meloidodera sp. | Big Thicket National Preserve, Texas | Water oak | COI | MK093159 |
| N7083 | H. avenae | Rio Grande County, Colorado | Barley | COI | MK093164 |
| N7095 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093160 |
| N7096 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093162 |
| N7243 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI ITS1 | MK093168 MK093180 |
| N7244 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI ITS1 | MK093169 MK093181 |
| N7245 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093170 |
| N7246 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI ITS1 | MK093171 MK093182 |
| N7247 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093172 |
| N7248 | H. trifolii | Rio Arriba County, New Mexico | Vineyard | COI | MK093173 |
| N7250 | H. trifolii | Rio Arriba County, New Mexico | Vineyard | COI ITS1 | MK093174 MK093183 |
| N7251 | H. avenae | Akershus, Norway | Oats | COI | MK093175 |
| N7253 | H. avenae | Akershus, Norway | Oats | COI | MK093176 |
| N8306 | H. schachtii | Platte County, Wyoming | Bean | COI | MK093165 |
| N8876 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093166 |
| N8877 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093161 |
| N8881 | Heterodera sp. | Dąbrówka, Poland | Peat meadow | COI | MK093167 |
| P119063 | H. medicaginis | Carbon County, Montana | Alfalfa | COI | MK093053 |
| P119064 | H. schachtii | Big Horn County, Montana | Alfalfa | COI | MK093054 |
| P125039 | H. schachtii | Platte County, Wyoming | Bean | COI | MK093055 |
| P125063 | H. schachtii | Laramie County, Wyoming | Sugar beet | COI | MK093056 |
| P145076 | H. schachtii | Platte County, Wyoming | Sugar beet | COI | MK093057 |
| P150049 | H. avenae | Montana | Barley | COI | MK093058 |
| P150069 | Vittatidera zeaphila | Tennessee | Corn | COI | MK093060 |
| P164043 | H. avenae | Montana | Barley | COI | MK093059 |
| P200034 | Cactodera sp. | Sheridan County, Nebraska | Potatoes-wheat | COI | MK093061 |
| P231089 | H. glycines | Unknown | Soybean | COI | MK093049 |
| P213017 | H. glycines | Unknown | Soybean | COI | MK093050 |
| P231088 | H. glycines | Unknown | Soybean | COI | MK093051 |
| P231091 | H. schachtii | Unknown | Soybean | COI | MK093052 |
| P243062 | H. glycines | Richardson County, Nebraska | Soybean | COI | MK093086 |
| P243063 | H. glycines | Richardson County, Nebraska | Soybean | COI | MK093087 |
| P243064 | H. glycines | Richardson County, Nebraska | Soybean | COI | MK093088 |
| P243069 | H. glycines | Seward County, Nebraska | Soybean | COI | MK093077 |
| P243080 | H. glycines | Lancaster County, Nebraska | Soybean | COI | MK093078 |
| P243083 | H. glycines | Lancaster County, Nebraska | Soybean | COI | MK093079 |
| P243085 | H. glycines | Cuming County, Nebraska | Soybean | COI | MK093080 |
| P243086 | H. glycines | Cuming County, Nebraska | Soybean | COI | MK093081 |
| P243094 | H. glycines | Nebraska | Soybean | COI | MK093084 |
| P243096 | H. glycines | Nebraska | Soybean | COI | MK093085 |
| P244003 | H. glycines | Cedar County, Nebraska | Soybean | COI | MK093095 |
| P244004 | H. glycines | Cedar County, Nebraska | Soybean | COI | MK093096 |
| P244020 | H. glycines | Holt County, Nebraska | Soybean | COI | MK093089 |
| P244021 | H. glycines | Holt County, Nebraska | Soybean | COI | MK093090 |
| P244041 | H. glycines | Buffalo County, Nebraska | Soybean | COI | MK093093 |
| P244042 | H. glycines | Buffalo County, Nebraska | Soybean | COI | MK093094 |
| P244060 | H. glycines | Burt County, Nebraska | Soybean | COI | MK093091 |
| P244062 | H. glycines | Burt County, Nebraska | Soybean | COI | MK093092 |
| P244065 | H. glycines | Stanton County, Nebraska | Soybean | COI | MK093082 |
| P244066 | H. glycines | Stanton County, Nebraska | Soybean | COI | MK093083 |
| P244072 | H. glycines | Cass County, Nebraska | Soybean | COI | MK093097 |
| P244074 | H. glycines | Cass County, Nebraska | Soybean | COI | MK093098 |
| P244076 | H. schachtii | Big Horn County, Montana | Pinto bean | COI | MK093065 |
| P244077 | H. schachtii | Big Horn County, Montana | Pinto bean | COI | MK093066 |
| P244078 | H. schachtii | Big Horn County, Montana | Black bean | COI | MK093067 |
| P244079 | H. schachtii | Big Horn County, Montana | Black bean | COI | MK093068 |
| P244081 | H. schachtii | Park County, Wyoming | Pinto bean | COI | MK093069 |
| P244082 | H. schachtii | Park County, Wyoming | Pinto bean | COI | MK093070 |
| P244084 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093071 |
| P244085 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093072 |
| P244086 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093073 |
| P244087 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093074 |
| P244088 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093075 |
| P244089 | H. schachtii | Platte County, Wyoming | Pinto bean | COI | MK093076 |
| P245019 | H. glycines | Alabama | Soybean | COI | MK093127 |
| P245023 | H. glycines | Alabama | Soybean | COI | MK093128 |
| P245025 | H. glycines | Alabama | Soybean | COI | MK093129 |
| P245027 | H. glycines | Alabama | Soybean | COI | MK093130 |
| P245029 | H. glycines | Alabama | Soybean | COI | MK093131 |
| P245033 | H. glycines | Alabama | Soybean | COI | MK093119 |
| P245035 | H. glycines | Alabama | Soybean | COI | MK093132 |
| P245038 | H. glycines | Alabama | Soybean | COI | MK093133 |
| P245041 | H. glycines | Alabama | Soybean | COI | MK093120 |
| P245043 | H. glycines | Alabama | Soybean | COI | MK093134 |
| P245044 | H. glycines | Cedar County, Nebraska | Soybean | COI | MK093109 |
| P245046 | H. glycines | Cedar County, Nebraska | Soybean | COI | MK093110 |
| P245089 | H. glycines | Oconee County, Georgia | Soybean | COI | MK093111 |
| P245090 | H. glycines | Oconee County, Georgia | Soybean | COI | MK093112 |
| P245094 | H. glycines | Burke County, Georgia | Soybean | COI | MK093135 |
| P245095 | H. glycines | Burke County, Georgia | Soybean | COI | MK093136 |
| P246006 | H. glycines | Boone County, Missouri | Soybean | COI | MK093121 |
| P246008 | H. glycines | Boone County, Missouri | Soybean | COI | MK093137 |
| P246010 | H. glycines | Livingston County, Missouri | Soybean | COI | MK093138 |
| P246014 | H. glycines | Knox County, Missouri | Soybean | COI | MK093113 |
| P246016 | H. glycines | Knox County, Missouri | Soybean | COI | MK093114 |
| P246018 | H. glycines | Atchison County, Missouri | Soybean | COI | MK093139 |
| P246021 | H. glycines | Atchison County, Missouri | Soybean | COI | MK093122 |
| P246033 | H. glycines | Fulton County, Ohio | Soybean | COI | MK093123 |
| P246035 | H. glycines | Fulton County, Ohio | Soybean | COI | MK093140 |
| P246042 | H. glycines | Sandusky County, Ohio | Soybean | COI | MK093124 |
| P246044 | H. glycines | Sandusky County, Ohio | Soybean | COI | MK093115 |
| P246047 | H. glycines | Sandusky County, Ohio | Soybean | COI | MK093116 |
| P247094 | H. glycines | Lee County, Arkansas | Soybean | COI | MK093141 |
| P247096 | H. glycines | Lee County, Arkansas | Soybean | COI | MK093142 |
| P247099 | H. glycines | Lee County, Arkansas | Soybean | COI | MK093143 |
| P248001 | H. glycines | Lee County, Arkansas | Soybean | COI | MK093144 |
| P248004 | H. glycines | Washington County, Arkansas | Soybean | COI | MK093145 |
| P248006 | H. glycines | Washington County, Arkansas | Soybean | COI | MK093146 |
| P248009 | H. glycines | McLeod County, Minnesota | Soybean | COI | MK093147 |
| P248010 | H. glycines | McLeod County, Minnesota | Soybean | COI | MK093125 |
| P248013 | H. glycines | Wilken County, Minnesota | Soybean | COI | MK093117 |
| P248016 | H. glycines | Wilken County, Minnesota | Soybean | COI | MK093118 |
| P248017 | H. glycines | Nicollet County, Minnesota | Soybean | COI | MK093148 |
| P248019 | H. glycines | Nicollet County, Minnesota | Soybean | COI | MK093149 |
| P248023 | H. glycines | Dodge County, Minnesota | Soybean | COI | MK093099 |
| P248024 | H. glycines | Dodge County, Minnesota | Soybean | COI | MK093100 |
| P248026 | H. glycines | Red Lake County, Minnesota | Soybean | COI | MK093101 |
| P248027 | H. glycines | Red Lake County, Minnesota | Soybean | COI | MK093102 |
| P248029 | H. glycines | Redwood County, Minnesota | Soybean | COI | MK093150 |
| P248031 | H. glycines | Redwood County, Minnesota | Soybean | COI | MK093151 |
| P248035 | H. glycines | Dakota County, Minnesota | Soybean | COI | MK093103 |
| P248036 | H. glycines | Dakota County, Minnesota | Soybean | COI | MK093104 |
| P248040 | H. glycines | Waseca County, Minnesota | Soybean | COI | MK093105 |
| P248041 | H. glycines | Waseca County, Minnesota | Soybean | COI | MK093106 |
| P248058 | H. cf. urticae | Faulkner County, Arkansas | Chickweed | COI | MK093155 |
| P248059 | H. cf. urticae | Faulkner County, Arkansas | Chickweed | COI | MK093156 |
| P248060 | H. trifolii | Washington County, Arkansas | Clover | COI | MK093157 |
| P248061 | H. trifolii | Washington County, Arkansas | Clover | COI | MK093158 |
| P248066 | H. glycines | Gentry County, Missouri | Soybean | COI | MK093107 |
| P248068 | H. glycines | Gentry County, Missouri | Soybean | COI | MK093108 |
| P248071 | H. glycines | Mercer County, Missouri | Soybean | COI | MK093152 |
| P248073 | H. glycines | Mercer County, Missouri | Soybean | COI | MK093153 |
| P248086 | H. glycines | Sussex County, Delaware | Soybean | COI | MK093154 |
| P248087 | H. glycines | Sussex County, Delaware | Soybean | COI | MK093126 |
| 105A13 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093177 |
| 105A14 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093178 |
| 105A15 | H. medicaginis | Kearny County, Kansas | Alfalfa | COI | MK093179 |
| Hsp90_3530 | H. medicaginis | Kearny County, Kansas | Alfalfa | Hsp90 | MH798843 |
| Hsp90_3531 | H. medicaginis | Kearny County, Kansas | Alfalfa | Hsp90 | MH798844 |
| Hsp90_3532 | H. medicaginis | Kearny County, Kansas | Alfalfa | Hsp90 | MH798845 |
| Hsp90_3533 | H. medicaginis | Kearny County, Kansas | Alfalfa | Hsp90 | MH798846 |
| Hsp90_2996 | H. trifolii | Alexandria, Egypt | Sugar beet | Hsp90 | MK095224 |
| Hsp90_2997 | H. trifolii | Alexandria, Egypt | Sugar beet | Hsp90 | MK095225 |
| Hsp90_2994 | H. trifolii | Alexandria, Egypt | Sugar beet | Hsp90 | MK095222 |
| Hsp90_2995 | H. trifolii | Alexandria, Egypt | Sugar beet | Hsp90 | MK095223 |
| Hsp90_2998 | H. trifolii | Alexandria, Egypt | Sugar beet | Hsp90 | MK095226 |
| HetITS105 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093184 |
| HetITS106 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093185 |
| HetITS107 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093186 |
| HetITS108 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093187 |
| HetITS109 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093188 |
| HetITS110 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093189 |
| HetITS111 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093190 |
| HetITS112 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093191 |
| HetITS113 | H. medicaginis | Kearny County, Kansas | Alfalfa | ITS | MK093192 |
Table 2
Morphological data on juveniles, all measurements in µm.
| Specimen No. | Length | Stylet | Tail | Hyaline |
|---|---|---|---|---|
| 1 | 440 | 25 | – | 25 |
| 2 | 421 | 25 | – | 21 |
| 3 | 425 | 25 | 45 | 25 |
| 4 | 420 | 25 | 50 | 25 |
| 5 | 421 | 24 | 43 | 22.5 |
| 6 | 420 | 23 | 46 | 23 |
| 7 | 447 | 25 | 45 | 28 |
| 8 | 475 | 24 | 52 | 25.5 |
| 9 | 462 | 25 | 45 | 22.5 |
| 10 | 395 | 25.5 | 45 | 25 |
| 11 | 491 | 25 | – | 25.5 |
| 12 | 485 | 25 | 50 | 21 |
| 13 | 413 | 25 | 48 | 25 |
| 14 | 410 | 26 | 40 | 20 |
| 15 | 415 | 25 | 45 | 23 |
| NID 7095 | 462.5 | 25 | 50 | 27 |
| NID 7096 | 442.5 | 24 | 51 | 30 |
| NID 7243 | 477.5 | 25 | 52.5 | 30 |
| NID 7244 | 455 | 26 | 50 | 25 |
| NID 7245 | 450 | 26 | 49 | 22.5 |
| NID 7246 | 425 | 25 | 48 | 27.5 |
| NID 7247 | 452.5 | 25 | 47.5 | 27.5 |
| NID 8876 | 472 | 27 | 52 | 28 |
| NID 8877 | 470 | 26 | 50 | 32 |
| Mean | 445.0 | 25.1 | 47.8 | 25.3 |
| SD | 27.2 | 0.8 | 3.2 | 3.0 |
| Maximum | 491 | 27 | 52.5 | 32 |
| Minimum | 395 | 23 | 40 | 20 |
|
Gerber and Maas (1982)
n = 100 Heterodera medicaginis | 462 (417–512) | 25 (24–26) | 51.8 (41–60) | 28.5 (22–33) |
|
Mulvey and Golden (1983)
H. glycines | 439 ± 6.7 (375–490) | 23 ± 0.01 (22–24) | 50.4 ± 1.0 (42–59) | 26.6 ± 0.7 (20–33) |
|
Mulvey and Golden (1983)
H. schachtii | 452 ± 49.7 | 25.6 ± 0.11 | 48.5 ± 0.73 | 27.1 ± 0.61 |
Table 3
Host trial for alfalfa cyst nematodes.
| Crop | ||||
|---|---|---|---|---|
| Alfalfa | Corn | Soybean | Tomato | |
| Month 1 | ||||
| Root weight (g) | 0.04 | 0.29 | 0.21 | 0.16 |
| Heterodera | ||||
| Females and cysts | 0 | 0 | 0 | 0 |
| Cysts/g | 0 | 0 | 0 | 0 |
| Heterodera infective juveniles | ||||
| Root incubation | 70 | 0 | 0 | 0 |
| J2/g | 1,750 | 0 | 0 | 0 |
| Meloidogyne J2 infective juveniles | ||||
| Root incubation | 210 | 4 | 10 | 3,100 |
| J2/g | 5,250 | 14 | 48 | 19,375 |
| Heterodera/Meloidogyne males | ||||
| Root incubation | 130 | 0 | 20 | 0 |
| Males/g | 3,250 | 0 | 95 | 0 |
| Month 2 | ||||
| Root weight (g) | 0.69 | 0.95 | 0.54 | 0.23 |
| Heterodera | ||||
| Females and cysts | 52 | 0 | 0 | 0 |
| Cysts/g | 75 | 0 | 0 | 0 |
| Heterodera infective juveniles | ||||
| Root incubation | 292 | 0 | 0 | 0 |
| J2/g | 423 | 0 | 0 | 0 |
| Meloidogyne J2 infective juveniles | ||||
| Root incubation | 0 | 0 | 308 | 12,040 |
| J2/g | 0 | 0 | 570 | 52,348 |
| Heterodera/Meloidogyne males | ||||
| Root incubation | 136 | 0 | 56 | 520 |
| Males/g | 197 | 0 | 104 | 2,261 |

Figure 1
Maximum likelihood tree inferred from the COI gene. Each new specimen is represented by an identification number, species name, and location. GenBank accessions are labeled by accession number, name, and the label ‘GB’ (GenBank). Bootstrap support values (%) are labeled in red, the species nodes of H. schachtii, H. medicaginis, and H. glycines are circled in blue.

Figure 2
Maximum likelihood tree inferred from the ITS1 gene. Bootstrap support values above 50% are labeled in red. GenBank accession specimen from Russia is boxed in yellow.

Figure 3
Phylogenetic relationships of Heterodera species as inferred from analysis of a partial Hsp90 gene using Bayesian inference. Posterior probabilities more than 50% are given next to nodes. Newly obtained sequences are shown in bold.

Figure 4
Heterodera medicaginis juvenile and male specimens. (A–G), juvenile specimens; (H–J), male specimen. (A) NID 7095, entire body; (B) NID 7243, entire body; (C) NID 7095, anterior; (D) NID 7243, anterior; (E) NID 7095, tail; (F) NID 7243, tail; (G) NID 7243, lateral lines; (H) PNID 169028, anterior; (I) PNID 169028, tail; (J) PNID 169028, entire body.

Figure 5
(A–D) light micrograph of vulval cones of H. medicaginis showing fenestra (A), bullae (B,D) and underbridge (B,D).

Figure 6
SEM micrographs of Heterodera medicaginis cysts from Kansas. (A) entire cyst 1, partial view of cyst 2; (B) entire cyst 3; (C) anterior region and excretory pore of cyst 1; (D) anterior region of cyst 3; (E) vulva and anus of cyst 2; (F) vulva of cyst 2 (left) and cyst 1 (right).