- Introduction
- Taxonomy
- Occurrence
- New Species
- Distribution
- Biology
- Dispersal
- Virulence/Host range/Infectivity
- Temperature
- Survival and Persistence
- Tritrophic Effects
- Compatibility
- Genetic Improvement
- Bioefficiency
- Mass Production
- Formulation and Storage
- Application
- Abiotic Factors
- Biotic Factors
- Integration in IPM
- Bioafety
- Nontarget Effects
- Commercial Products
- Quality
- Techniques
- Chromosomes
- Associated Bacteria
Steinernematidae - Diagnostic Characters
Family Steinernematidae Chitwood & Chitwood, 1937
Diagnostic characters:
(Rhabditida. Rhabditoidea. Obligate entomopathogenic nematodes capable of killing wide range of insects, due to septicaemia caused by the symbiotic bacteria (Xenorhabdus spp). Adult stages found only in the hemolymph of the infected insect, while third stage is infective, the only stage found in the soil. One, two or more generations inside the host.
Adults:
Always amphimictic. Stylet absent. Six lips partially or completely fused; each lip with a labial papilla at its tip; four cephalic papillae. Amphidial aperture located on lateral lips. Stoma short and wide, represented by thick ring shaped cheilorhabdions, with distinct pro and mesorhabdions, and reduced metarhabdions. Oesophagous muscular with cylindrical procorpus, often with non valved metacorporal swelling, followed by narrow isthmus, expanding into a spherical bulb containing reduced triradite valvular apparatus. Nerve ring encircling the isthmus. Excretory pore always located anterior to nerve ring. Tail tip with or without mucron.
Females:
Amphidelphic, didelphic with reflexed ovaries. Vulva median with vulval lips, functional only during mating and initial stages of oviposition. Mature females ovoviviparous; developing larvae consume the entire body contents and eventually killing the females. The female cuticle degenerates and the larvae are released. First generation females much longer than the females of subsequent generations.
Males: Testis single, reflexed at tip. Spicules paired, separate, ventrally arcuate, with or without vellum. Gubernaculum present. Bursa absent. Genital papillae nipple shaped, numbering 23-25. Infective juveniles: Third stage juvenile is the infective or dauer stage. Cuticle bearing 5-9 incisures (mostly 8-9) in the lateral field. Stoma and anus closed. Oesophagous collapsed with a basal swelling enclosing a degenerated valve. Anterior part of intestine modified to form a vesicle which contain the symbiotic bacteria. Excretory pore located anterior to nerve ring. Mouth region not armed with dorsal hook. Tail elongated conoid with distinct hyaline part.
GENUS STEINERNEMA AND NEOSTEINERNEMA
Abbreviations used in diagnoses: IJ = infective juvenile; EP = distance from anterior end to excretory pore; SP = spicule length; D% = EP of MALE divided by esophagus length x 100; E% = EP of IJ divided by tail length x 100; GS% = gubernaculum divided by spicule x 100; SW = spicule divided by anal body width; ABW=anal body width, um=micrometers, T=IJ tail length.
All adult data are from the first generation
DIAGNOSTIC CHARACTERS
Species names are arranged in descending order of spicule length
Steinernema intermedium
Spicule length=91 um (84-100), IJ length=671 um (608-800), EP= 65 um (59-69), T=66 um (53-74), E%=96, mucron absent, dorsal depression of IJ tail. In male, mele D%=67 (58-76), SW=1.24 (1.03-1.39), GS=0.69 (0.62-0.77), spicule well curved with blunt tip, rostrum prominent, velum large.
Steinernema arenarium (=anomalae)
Spicule length= 84 um (81-91), IJ length=1034 um (724-1408), EP=83 um (76-86), T=75 um (64-84), E%=119, hookless spicule with ball-like tip, D%=93 (male), SW=2.10, GS=0.65, in ventral view, cuneus of gubernaculum V-shaped, mucron absent.
Steinernema scapterisci
Spicule length=83 um (72-92), IJ length= 572 um (517-609), T=54 um (48-60), E%=73, in male, male D%=38 (32-44), SW= 2.52 (2.04-2.80), GS=0.78 (0.69-0.84), mucron present; female with large double-flapped epiptygma, and excretory duct with elliptically-shaped structure.
Steinernema karii
Spicule length=83 um (73-91), IJ length=932 um (876-982), EP= 74 um (68-80), T=74 um (64-80), E%=96, mucron absent, male D%=66 (53-78), SW=1.50, GS=0.7, spicule well curved with blunt tip, spicule head twice as long as wide, velum thin; gubernaculum with posterior end bifurcate, cuneus present.
Steinernema diaprepesi
Spicule length=79 um (71-90), IJ length=1002 um (880-1133), EP=74 um (66-83), T=83 um (65-91), E%=89.6 (78-114), spicule head elongate, length/width=1.4-2.0, shaft very short, lamina thick, terminus blunt with longtudinal depression, velum present. D% of male=80 (68-86), SW=1.8 (1.5-2.0), GS=0.69 (0.59-0.79), epiptygma low, double flapped, male terminus without mucron, young female terminus usually with 5 papillae-like structures, dissapearing in fully mature females.
Steinernema puertoricense
Spicule length=78 um (71-88), IJ length=1171 um (1057-1238), EP=95 um (90-102), T=94 um (98-107), E%=101, spicule well curved with tip without a hook, mucron absent, male D%=77, SW=1.52, GS=0.51, double flapped-epiptygma present in females;
Steinernema siamkayai
Spicule length=77.5 um (75-80), IJ length= 446 um (398-495) , EP= 35 um (29-38), T= 35.5 um (), E%=96 (85-112), spicule with prominent head, shaft indistinct, rostrum present; gubernaculum slender, tapering gradually posteriorly, male D%=42 (35-49), SW=1.7 (1.4-2.2), GS=0.7 (0.6-0.8) epiptygma present, mucron present.
Steinernema glaseri
Spicule length=77 um (64-90), IJ length=1130 um (864-1448) , EP=102 um (87-110), T=78 um (62-87), E%=131, spicule with prominent shaft and hooked tip, in ventral view, gubernaculum tapering gradually anteriorly, cuneus Y-shaped, male D%=70, SW=2.05 (1.64-2.43), GS=0.71 (0.64-0.85), epiptygma absent, mucron absent.
Steinernema longicaudum
Spicule length=77 um (?), IJ length=1063 um (?), EP=81 um, T=95 um, E%=85, hookless spicule tip, male D%=62, SW=1.60, GS=0.62; spicule narrows suddenly to form tip with flattened terminus, epiptygma absent, mucron absent.
Steinernema caudatum
Spicule length=75 um, IJ length=1106 um (933-1296), EP=82 um (76-89), T=88 um (80-100), E%=94 (87-100), male D%=71, SW=2.22, GS=0.69. spicule tip truncate, mucron absent; female tail sometimes with 2 projections.
Steinernema thanhi
Spicule length=72 um (67-78), IJ length=851 um (720-960), EP=75 um (68-84), T=63 um (52-72), E%=119 (101-138), male D%=73 (64-82), SW=1.8 (1.5-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, velum thin, mucron absent.
Steinernema oregonense
Spicule length=71 um (65-73), IJ length=980 um (820-1110), EP=66 um (60-72), T=70 um (64-78), E%=100 (90-110), male D%=73 (64-75), SW=1.51, GS=0.79, spicule moderately curved, spicule head enlarged, tapering anteriorly, mucron absent.
Steinernema ceratophorum
Spicule length=71 um (54-90), IJ length=706 um (591-800), EP= 55 um (47-70), T=66 um (56-74), E%=84, male D%=51 (33-65), SW=1.4 (1.0-2.0), GS=0.6 (0.4-0.8), mucron absent in first and second generation, spicule curved with blunt tip, velum large extending nearly to spicule tip, gubernaculum boat-shaped with posterior end bifurcate, cuneus small.
Steinernema loci
Spicule length=71 um (60-80), IJ length=986 um (896-1072), EP=80 um (71-86), T=75 um (66-83), E%=107 (94-120), male D%=73 (61-80), SW=1.9 (1.7-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, 1/3 of spicule length, tail without mucron.
Steinernema affine
Spicule length=70 um (67-86), IJ length= 693 um (608-880), EP=62 um (51-69), T=66 um (64-74), E%=94, internal spine in IJ tail, male D%=61, SW=1.17, GS=0.66, mucron present, small.
Steinernema feltiae (=bibionis)
Spicule length=70 um (65-77), IJ length= 849 um (736-950), EP=62 um (53-67), T=81 um (70-92), E%=78, male D%=60, mucron long, tail=81 m, SW=1.13 (0.9-1.30), GS%=59 (0.52-0.62), spicule slightly curved, spicule head twice as long as wide.
Steinernema monticolum
Spicule length=70 um (61-80), IJ length=706 um (612-821), EP=58 um (54-62), T=77 um (71-95), E%=76 (63-86), male D%=55 (49-51), SW=1.40 (1.20-1.5), GS=0.60 (0.5-0.7), spicules wide, anterior end rounded, well curved, shaft short but distinct, velum large.
Steinernema ritteri
Spicule length=69 um (58-75), IJ length=510 um(470-590), EP=38 um (32-40), T=51um (44-56), E%=88, mucron absent, male D%=47, SW=1.56, GS=0.64, female with epiptygma.
Steinernema pakistanense
Spicule length = 68 ± 3.6 um (62-73), labial region of IJ bearing two horn-like structures, IJ length= 683±21 um (649-716), EP=54±2.2 um (49-58), T=58±2.1 um (53-62), E%=91±5 (87-102), male D%=60 ± 3 (50-60), SW = 1.8 ± 0.1(1.0-2.2), GS = 0.6 ± 0.04 (0.5-0.6), spicule head elongate, broad not continuous with the blade, tip pointed, velum present, 10% of male with mucron.
Steinernema riobrave
Spicule length=67 um (63-75), IJ length= 622 um (561-701), EP=56 um (51-64), T=54 um (46-59), E%=105, spicule sickle-shaped, spicule head tapering anteriorly, in ventral view, width of neck of gubernaculum large, cuneus Y-shaped, mucron absent, male D%=71, SW=1.14, GS=0.76.
Steinernema carpocapsae
Spicule length=66 um (58-77), IJ length=558 um (438-650), EP=38 um (30-60), T=53 um (46-61), E%=66, spicule head wider than long, ventrally projected, spicule tip pointed or bluntly pointed; in ventral view, cuneus arrowhead-shaped or Y-shaped, mucron present, male D%=41, SW about 1.72, GS=0.71.
Steinernema bicornutum
Spicule length=65 um (53-70), IJ length=769 um (648-873), EP=61 um (53-65), T=72 um (63-78), E%=84 (80-100), male D%=52 (50-60), SW=2.22, GS=0.72, spicule curved, spicule head typified by ventral projection and a width greater than length, blade well curved anteriorly or at mid region, posterior part slightly curved ot straight, velum present; in ventral view, cuneus arrowhead-shaped, mucron absent.
Steinernema abbasi
Spicule length=65 um (57-74), IJ length=541 um (496-579), EP= 48 um (46-51), T=56 um (52-61), E%=86, male D%=60, SW=1.56 (1.07-1.87), GS=0.7 (0.58-0.85), mucron absent, spicule curved, velum large.Gubernaculum boat-shaped.
Steinernema kushidai
Spicule length= 63 um (48-72), IJ length=589 um (524-662), EP=46 um (42-50), T=50 um (44-59), E%=92; spicule head truncate or rounded anteriorly, almost as long as wide, blade with large anterior end, rostrum prominent, velum present; mucron absent, male D%=51; SW=1.50, GS=0.70.
Steinernema sangi
Spicule length=63 um (58-80), IJ length=753 um (704-784), EP=51 um (46-54), T=81 um (76-89), E%=62 (56-70), male D%=49 ((42-62), SW=1.5 (1.2-1.6). GS=0.6 (0.5-0.7), mucron small, spicule head short, velum large.
Steinernema thermophilum
spicule length=61 um (44-72), IJ length=555 um (510-620), EP=40 um (37-46), T=45 um (40-52), E%=90 (81-102), male D%=63 (50-87), SW=1.7 (1.2-2.8), GS=0.6(0.5-0.7), spicule head short, spicule tip pointed, velum present.
Steinernema cubanum
Spicule length=58 um (50-67), IJ length=1283 um (1149-1508), EP=106 um (101-114), T=67 um (61-77), E%=160, male D%=70, SW=1.40, GS=0.67, spicule head continuous with spicule blade dorsally, spicule tip hookless, in ventral view, cuneus of gubernaculum Y-shaped, velum narrow; mucron absent
Steinernema neocurtillae
Spicule length=58 um (52-64), IJ length=885 um (741-988), EP=18 um, E%=23, EP extremely short, T=80 um (64-97), male D%=12, SW=1.43 (1.18.1.64), GS=0.89 (0.82-0.93), spicule short, spicule tip with a prominent depression on ventral side; mucron present, short.
Steinernema kraussei
Spicule length=49 um (42-53), IJ length= 951 um (797-1102), EP=63 um (56-66), T=79 um (63-86), E%=80, spicule well or moderately curved, mucron small, male D%=53, SW=1.10, GS=0.67.
Steinernema rarum
Spicule length=47 um (42-52), IJ length=511 um (443-573), EP=38 um (32-40), T=51 um (44-56), E%=72, morphometrics of this nematode are less than those of other steinernematids, mucron present, male D%=50, SW=0.94, GS=0.71. Spicules with rounded anterior end, shaft present, sometimes indistinct, velum wide. Gubernaculum thick, cuneus present.
Neosteinernema longicurvicauda
Spicule=61 um (52-67), IJ length=926 um (789-1084), EP=68 um (61-76), T=167 um (141-190), E%=41, male D%=44 (30-54), SW=1.03 (0.80-1.50), GS=0.97 (0.84-1.08), male terminus digitate, spicule foot-shaped, 27-29 genital papillae, phasmids large, female tail longer than ABW, IJ tail long, curved, as long as esophagus length.
Family Steinernematidae
Diagnosis:
(After Nguyen and Smart, 1994): Cephaloboidea, Rhabditida. Obligate insect parasites. Infective juveniles carry symbiotic bacteria in the bacterial chamber of the intestine. Both males and females are necessary for reproduction.
Females: Large, size variable. Cuticle smooth or annulated. Lateral fields absent. Excretory pore distinct. Head rounded or truncate, rarely offset. Six lips present, partly r completely fused, each lip with one labial papilla (Fig. IA), sometimes additional papilla-like structures present near labial papillae. Four cephalic papillae. Amphids present, small. Stoma collapsed; cheilorhabdions pronounced, forming a ring resembling two large sclerotized dots in lateral view. Other parts of stoma forming an asymmetrical funnel with thick anterior end. Esophagus rhabditoid with metacorpus slightly swollen, narrow isthmus surrounded by nerve ring, and large basal bulb with reduced valve. Esophago-intestinal valve usually pronounced. Reproductive system didelphic, amphidelphic, reflexed. Vulva at mid-body, sometimes on a protuberance (Fig. 1B), with (Fig. 1C) or without (Fig. 1B) epiptygma. Females oviparous or ovoviviparous with juveniles developing up to the infective stage (IJ) before emerging from the body of the female. Tail longer or shorter than anal body width, with or without prominent phasmids.
Males : Smaller than female. Anterior end usually with six labial papillae, four large cephalic papillae and usually with perioral disc. Esophagus similar to that of the female. Testis single, reflexed; spicules paired; gubernaculum long, sometimes as long as spicule; bursa absent. Tail tip rounded, digitate or mucronate. One single and 10 to 14 pairs of genital papillae present with 7 to 10 pairs precloacal.
Infective juveniles (= third-stage infective juvenile):Stoma collapsed. Body slender, with or without a sheath (cuticle of second-stage juvenile). Cuticle annulated. Lateral fields present with 4-9 incisures and 3-8 smooth ridges . Esophagus and intestine appearing reduced. Excretory pore distinct. Tail conoid or filiform. Phasmids, located about mid-tail, prominent, inconspicuous, or not observed.
Type genus:Steinernema Travassos, 1927
Syn.: Neoaplectana Steiner, 1929
Other genus: Neosteinernema Nguyen & Smart, 1994
Family Steinernematidae Chitwood & Chitwood, 1937
Diagnostic characters:
(Rhabditida. Rhabditoidea. Obligate entomopathogenic nematodes capable of killing wide range of insects, due to septicaemia caused by the symbiotic bacteria (Xenorhabdus spp). Adult stages found only in the hemolymph of the infected insect, while third stage is infective, the only stage found in the soil. One, two or more generations inside the host.
Adults:
Always amphimictic. Stylet absent. Six lips partially or completely fused; each lip with a labial papilla at its tip; four cephalic papillae. Amphidial aperture located on lateral lips. Stoma short and wide, represented by thick ring shaped cheilorhabdions, with distinct pro and mesorhabdions, and reduced metarhabdions. Oesophagous muscular with cylindrical procorpus, often with non valved metacorporal swelling, followed by narrow isthmus, expanding into a spherical bulb containing reduced triradite valvular apparatus. Nerve ring encircling the isthmus. Excretory pore always located anterior to nerve ring. Tail tip with or without mucron.
Females:
Amphidelphic, didelphic with reflexed ovaries. Vulva median with vulval lips, functional only during mating and initial stages of oviposition. Mature females ovoviviparous; developing larvae consume the entire body contents and eventually killing the females. The female cuticle degenerates and the larvae are released. First generation females much longer than the females of subsequent generations.
Males: Testis single, reflexed at tip. Spicules paired, separate, ventrally arcuate, with or without vellum. Gubernaculum present. Bursa absent. Genital papillae nipple shaped, numbering 23-25. Infective juveniles: Third stage juvenile is the infective or dauer stage. Cuticle bearing 5-9 incisures (mostly 8-9) in the lateral field. Stoma and anus closed. Oesophagous collapsed with a basal swelling enclosing a degenerated valve. Anterior part of intestine modified to form a vesicle which contain the symbiotic bacteria. Excretory pore located anterior to nerve ring. Mouth region not armed with dorsal hook. Tail elongated conoid with distinct hyaline part.
Abbreviations used in diagnoses: IJ = infective juvenile; EP = distance from anterior end to excretory pore; SP = spicule length; D% = EP of MALE divided by esophagus length x 100; E% = EP of IJ divided by tail length x 100; GS% = gubernaculum divided by spicule x 100; SW = spicule divided by anal body width; ABW=anal body width, um=micrometers, T=IJ tail length.
All adult data are from the first generation
DIAGNOSTIC CHARACTERS
Species names are arranged in descending order of spicule length
Steinernema intermedium
Spicule length=91 um (84-100), IJ length=671 um (608-800), EP= 65 um (59-69), T=66 um (53-74), E%=96, mucron absent, dorsal depression of IJ tail. In male, mele D%=67 (58-76), SW=1.24 (1.03-1.39), GS=0.69 (0.62-0.77), spicule well curved with blunt tip, rostrum prominent, velum large.
Steinernema arenarium (=anomalae)
Spicule length= 84 um (81-91), IJ length=1034 um (724-1408), EP=83 um (76-86), T=75 um (64-84), E%=119, hookless spicule with ball-like tip, D%=93 (male), SW=2.10, GS=0.65, in ventral view, cuneus of gubernaculum V-shaped, mucron absent.
Steinernema scapterisci
Spicule length=83 um (72-92), IJ length= 572 um (517-609), T=54 um (48-60), E%=73, in male, male D%=38 (32-44), SW= 2.52 (2.04-2.80), GS=0.78 (0.69-0.84), mucron present; female with large double-flapped epiptygma, and excretory duct with elliptically-shaped structure.
Steinernema karii
Spicule length=83 um (73-91), IJ length=932 um (876-982), EP= 74 um (68-80), T=74 um (64-80), E%=96, mucron absent, male D%=66 (53-78), SW=1.50, GS=0.7, spicule well curved with blunt tip, spicule head twice as long as wide, velum thin; gubernaculum with posterior end bifurcate, cuneus present.
Steinernema diaprepesi
Spicule length=79 um (71-90), IJ length=1002 um (880-1133), EP=74 um (66-83), T=83 um (65-91), E%=89.6 (78-114), spicule head elongate, length/width=1.4-2.0, shaft very short, lamina thick, terminus blunt with longtudinal depression, velum present. D% of male=80 (68-86), SW=1.8 (1.5-2.0), GS=0.69 (0.59-0.79), epiptygma low, double flapped, male terminus without mucron, young female terminus usually with 5 papillae-like structures, dissapearing in fully mature females.
Steinernema puertoricense
Spicule length=78 um (71-88), IJ length=1171 um (1057-1238), EP=95 um (90-102), T=94 um (98-107), E%=101, spicule well curved with tip without a hook, mucron absent, male D%=77, SW=1.52, GS=0.51, double flapped-epiptygma present in females;
Steinernema siamkayai
Spicule length=77.5 um (75-80), IJ length= 446 um (398-495) , EP= 35 um (29-38), T= 35.5 um (), E%=96 (85-112), spicule with prominent head, shaft indistinct, rostrum present; gubernaculum slender, tapering gradually posteriorly, male D%=42 (35-49), SW=1.7 (1.4-2.2), GS=0.7 (0.6-0.8) epiptygma present, mucron present.
Steinernema glaseri
Spicule length=77 um (64-90), IJ length=1130 um (864-1448) , EP=102 um (87-110), T=78 um (62-87), E%=131, spicule with prominent shaft and hooked tip, in ventral view, gubernaculum tapering gradually anteriorly, cuneus Y-shaped, male D%=70, SW=2.05 (1.64-2.43), GS=0.71 (0.64-0.85), epiptygma absent, mucron absent.
Steinernema longicaudum
Spicule length=77 um (?), IJ length=1063 um (?), EP=81 um, T=95 um, E%=85, hookless spicule tip, male D%=62, SW=1.60, GS=0.62; spicule narrows suddenly to form tip with flattened terminus, epiptygma absent, mucron absent.
Steinernema caudatum
Spicule length=75 um, IJ length=1106 um (933-1296), EP=82 um (76-89), T=88 um (80-100), E%=94 (87-100), male D%=71, SW=2.22, GS=0.69. spicule tip truncate, mucron absent; female tail sometimes with 2 projections.
Steinernema thanhi
Spicule length=72 um (67-78), IJ length=851 um (720-960), EP=75 um (68-84), T=63 um (52-72), E%=119 (101-138), male D%=73 (64-82), SW=1.8 (1.5-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, velum thin, mucron absent.
Steinernema oregonense
Spicule length=71 um (65-73), IJ length=980 um (820-1110), EP=66 um (60-72), T=70 um (64-78), E%=100 (90-110), male D%=73 (64-75), SW=1.51, GS=0.79, spicule moderately curved, spicule head enlarged, tapering anteriorly, mucron absent.
Steinernema ceratophorum
Spicule length=71 um (54-90), IJ length=706 um (591-800), EP= 55 um (47-70), T=66 um (56-74), E%=84, male D%=51 (33-65), SW=1.4 (1.0-2.0), GS=0.6 (0.4-0.8), mucron absent in first and second generation, spicule curved with blunt tip, velum large extending nearly to spicule tip, gubernaculum boat-shaped with posterior end bifurcate, cuneus small.
Steinernema loci
Spicule length=71 um (60-80), IJ length=986 um (896-1072), EP=80 um (71-86), T=75 um (66-83), E%=107 (94-120), male D%=73 (61-80), SW=1.9 (1.7-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, 1/3 of spicule length, tail without mucron.
Steinernema affine
Spicule length=70 um (67-86), IJ length= 693 um (608-880), EP=62 um (51-69), T=66 um (64-74), E%=94, internal spine in IJ tail, male D%=61, SW=1.17, GS=0.66, mucron present, small.
Steinernema feltiae (=bibionis)
Spicule length=70 um (65-77), IJ length= 849 um (736-950), EP=62 um (53-67), T=81 um (70-92), E%=78, male D%=60, mucron long, tail=81 m, SW=1.13 (0.9-1.30), GS%=59 (0.52-0.62), spicule slightly curved, spicule head twice as long as wide.
Steinernema monticolum
Spicule length=70 um (61-80), IJ length=706 um (612-821), EP=58 um (54-62), T=77 um (71-95), E%=76 (63-86), male D%=55 (49-51), SW=1.40 (1.20-1.5), GS=0.60 (0.5-0.7), spicules wide, anterior end rounded, well curved, shaft short but distinct, velum large.
Steinernema ritteri
Spicule length=69 um (58-75), IJ length=510 um(470-590), EP=38 um (32-40), T=51um (44-56), E%=88, mucron absent, male D%=47, SW=1.56, GS=0.64, female with epiptygma.
Steinernema pakistanense
Spicule length = 68 ± 3.6 um (62-73), labial region of IJ bearing two horn-like structures, IJ length= 683±21 um (649-716), EP=54±2.2 um (49-58), T=58±2.1 um (53-62), E%=91±5 (87-102), male D%=60 ± 3 (50-60), SW = 1.8 ± 0.1(1.0-2.2), GS = 0.6 ± 0.04 (0.5-0.6), spicule head elongate, broad not continuous with the blade, tip pointed, velum present, 10% of male with mucron.
Steinernema riobrave
Spicule length=67 um (63-75), IJ length= 622 um (561-701), EP=56 um (51-64), T=54 um (46-59), E%=105, spicule sickle-shaped, spicule head tapering anteriorly, in ventral view, width of neck of gubernaculum large, cuneus Y-shaped, mucron absent, male D%=71, SW=1.14, GS=0.76.
Steinernema carpocapsae
Spicule length=66 um (58-77), IJ length=558 um (438-650), EP=38 um (30-60), T=53 um (46-61), E%=66, spicule head wider than long, ventrally projected, spicule tip pointed or bluntly pointed; in ventral view, cuneus arrowhead-shaped or Y-shaped, mucron present, male D%=41, SW about 1.72, GS=0.71.
Steinernema bicornutum
Spicule length=65 um (53-70), IJ length=769 um (648-873), EP=61 um (53-65), T=72 um (63-78), E%=84 (80-100), male D%=52 (50-60), SW=2.22, GS=0.72, spicule curved, spicule head typified by ventral projection and a width greater than length, blade well curved anteriorly or at mid region, posterior part slightly curved ot straight, velum present; in ventral view, cuneus arrowhead-shaped, mucron absent.
Steinernema abbasi
Spicule length=65 um (57-74), IJ length=541 um (496-579), EP= 48 um (46-51), T=56 um (52-61), E%=86, male D%=60, SW=1.56 (1.07-1.87), GS=0.7 (0.58-0.85), mucron absent, spicule curved, velum large.Gubernaculum boat-shaped.
Steinernema kushidai
Spicule length= 63 um (48-72), IJ length=589 um (524-662), EP=46 um (42-50), T=50 um (44-59), E%=92; spicule head truncate or rounded anteriorly, almost as long as wide, blade with large anterior end, rostrum prominent, velum present; mucron absent, male D%=51; SW=1.50, GS=0.70.
Steinernema sangi
Spicule length=63 um (58-80), IJ length=753 um (704-784), EP=51 um (46-54), T=81 um (76-89), E%=62 (56-70), male D%=49 ((42-62), SW=1.5 (1.2-1.6). GS=0.6 (0.5-0.7), mucron small, spicule head short, velum large.
Steinernema thermophilum
spicule length=61 um (44-72), IJ length=555 um (510-620), EP=40 um (37-46), T=45 um (40-52), E%=90 (81-102), male D%=63 (50-87), SW=1.7 (1.2-2.8), GS=0.6(0.5-0.7), spicule head short, spicule tip pointed, velum present.
Steinernema cubanum
Spicule length=58 um (50-67), IJ length=1283 um (1149-1508), EP=106 um (101-114), T=67 um (61-77), E%=160, male D%=70, SW=1.40, GS=0.67, spicule head continuous with spicule blade dorsally, spicule tip hookless, in ventral view, cuneus of gubernaculum Y-shaped, velum narrow; mucron absent
Steinernema neocurtillae
Spicule length=58 um (52-64), IJ length=885 um (741-988), EP=18 um, E%=23, EP extremely short, T=80 um (64-97), male D%=12, SW=1.43 (1.18.1.64), GS=0.89 (0.82-0.93), spicule short, spicule tip with a prominent depression on ventral side; mucron present, short.
Steinernema kraussei
Spicule length=49 um (42-53), IJ length= 951 um (797-1102), EP=63 um (56-66), T=79 um (63-86), E%=80, spicule well or moderately curved, mucron small, male D%=53, SW=1.10, GS=0.67.
Steinernema rarum
Spicule length=47 um (42-52), IJ length=511 um (443-573), EP=38 um (32-40), T=51 um (44-56), E%=72, morphometrics of this nematode are less than those of other steinernematids, mucron present, male D%=50, SW=0.94, GS=0.71. Spicules with rounded anterior end, shaft present, sometimes indistinct, velum wide. Gubernaculum thick, cuneus present.
Neosteinernema longicurvicauda
Spicule=61 um (52-67), IJ length=926 um (789-1084), EP=68 um (61-76), T=167 um (141-190), E%=41, male D%=44 (30-54), SW=1.03 (0.80-1.50), GS=0.97 (0.84-1.08), male terminus digitate, spicule foot-shaped, 27-29 genital papillae, phasmids large, female tail longer than ABW, IJ tail long, curved, as long as esophagus length.
Family Steinernematidae
Diagnosis:
(After Nguyen and Smart, 1994): Cephaloboidea, Rhabditida. Obligate insect parasites. Infective juveniles carry symbiotic bacteria in the bacterial chamber of the intestine. Both males and females are necessary for reproduction.
Females: Large, size variable. Cuticle smooth or annulated. Lateral fields absent. Excretory pore distinct. Head rounded or truncate, rarely offset. Six lips present, partly r completely fused, each lip with one labial papilla (Fig. IA), sometimes additional papilla-like structures present near labial papillae. Four cephalic papillae. Amphids present, small. Stoma collapsed; cheilorhabdions pronounced, forming a ring resembling two large sclerotized dots in lateral view. Other parts of stoma forming an asymmetrical funnel with thick anterior end. Esophagus rhabditoid with metacorpus slightly swollen, narrow isthmus surrounded by nerve ring, and large basal bulb with reduced valve. Esophago-intestinal valve usually pronounced. Reproductive system didelphic, amphidelphic, reflexed. Vulva at mid-body, sometimes on a protuberance (Fig. 1B), with (Fig. 1C) or without (Fig. 1B) epiptygma. Females oviparous or ovoviviparous with juveniles developing up to the infective stage (IJ) before emerging from the body of the female. Tail longer or shorter than anal body width, with or without prominent phasmids.
Males : Smaller than female. Anterior end usually with six labial papillae, four large cephalic papillae and usually with perioral disc. Esophagus similar to that of the female. Testis single, reflexed; spicules paired; gubernaculum long, sometimes as long as spicule; bursa absent. Tail tip rounded, digitate or mucronate. One single and 10 to 14 pairs of genital papillae present with 7 to 10 pairs precloacal.
Infective juveniles (= third-stage infective juvenile):Stoma collapsed. Body slender, with or without a sheath (cuticle of second-stage juvenile). Cuticle annulated. Lateral fields present with 4-9 incisures and 3-8 smooth ridges . Esophagus and intestine appearing reduced. Excretory pore distinct. Tail conoid or filiform. Phasmids, located about mid-tail, prominent, inconspicuous, or not observed.
Type genus:Steinernema Travassos, 1927
Syn.: Neoaplectana Steiner, 1929
Other genus: Neosteinernema Nguyen & Smart, 1994
Steinernema spp.
Key to the species* of Steinernema
(Based on infective juveniles, females and males)
1. Infective Juvenile's ( IJ's) average length < 600 ?m............... 2
- IJ's average length > 600 but < 700 ?m.............. 10
- IJ's average length > 700 but < 1000 ?m................. 12
- IJ's average length > 1000 ?m.................. 19
2. IJ's average excretory pore < 40 ?m; Mucron always present in males
and females of both the generations..................3
- IJ's excretory pore > 40 ?m; Mucron may or may not be present in adults......7
3. IJ's average tail length < 40 ?m ( 31-41) ............ S.siamkayai
- IJ's average tail length > 40?m .............4
4. Average spicule length 72-83 ?m; SW average 2-2.5............. 5
- Average spicule length 47-66 ?m; SW average 0.9-1.7............. 6
5. In males, average spicule length =72 ( 63-78?m); D%= 44 ( 30-60);
SW= 2.0(1.4-3); Mucron may or may not be present in 1st generation
males........................... S. tami
- In males, average spicule length = 83 ( 72-92); D%= 38 ( 32-44);
SW=2.5 ( 2-2.8); Mucron always present in 1st generation males
.....................S. scapterisci
6. IJ's D%=35 (30-39); Spicule=47 ( 42-52)?m; gubernaculum = 34 (23-38)?m;
SW= 0.9 ( 0.9-1.05).......................S. rarum
- IJ's D%=26 (23-28); Spicule= 66 ( 58-77) ?m; gubernaculum= 47 (39-55)?m;
SW=1.7 ( 1.4-2.0)..............................S. carpocapsae
7. IJ's average excretory pore >47 (46-51)?m; D%= 53 (51-58); Tail= 56 (52-61)?m;
Mucron absent in adults of both sexes in both generations.................S. abbasi
- IJ's average excretory pore < 47 (40-46) ?m; Average D%=41-46;
Average tail length=45-50 ?m; Mucron present in 2nd generation
females but absent in 1st generation females
................................ 8
8. Mucron present in females and males of 2nd generation, but absent in 1st generation;
Average excretory pore = 43-46?m; Oesophagous = 85-120 ?m;
Average tail length=49-50 ?m ......................... 9
- Mucron present only in 2nd generation females but absent in other stages;
Excretory pore= 40 (37-46) ?m; Oesophagous= 70-84?m; Tail= 45 (40-52) ?m
.................................... S. thermophilum
9. IJ's length= 589 (524-662) ?m; Excretory pore= 46 (42-50) ?m;
Oesophagous= 111(106-120) ?m; D%= 41 (38-44); Spicules =63 (48-72) ?m
........................ S. kushidai
- IJ's length = 510 (470-609)?m; Excretory pore= 43 (40-46) ?m;
Oesophagous= 91.5(85-95); D%=46(44-50); Spicules= 69 (58-75) ?m.
...........................S. ritteri
10. IJ's average excretory pore= 56 ?m; Oesophagous = 114 ?m (109-116);
Tail= 54 ( 46-59)?m; E%> 100; Males' average D% = 71(60-80)
............................... S. riobrave
- IJ's average excretory pore> 56?m; Average oesophagous > 114?m;
E%<100; Males' average D% <71............................11
11.Mucron present in adults of both sexes excepting first generation females;
IJ's with refringent spine at tail tip; Spicules= 70 (67-86)?m;
Gubernaculum=46 (37-56)?m.......................S. affine
- Mucron always absent in adults in both generations; IJs without
refractile spine at tail terminus; Spicules= 91(84-100)?m;
Gubernaculum= 64 (56-75)?m............................S. intermedium
12. Mucron always present in adults of both sexes in both generations
..................................13
- Mucron may or may not be present in adults
............................. 15
13. IJ's average length> 900?m; Ratio c > 11Spicules = 49 ( 42-53)?m;
Gubernaculum= 33 (29-37)?m........................ S. kraussei
- IJ's average length <900?m; Ratio c<11; Spicules= 70 ( 61-80) ?m;
Gubernaculum= average 41-45 ( range 34-54); Ratio c= 12.1
.............................14
14. IJ's body length = 706 (612-821)?m; Excretory pore=58 ?m; Ratio c= 9.3
Oesophagous= 124( 120-131)?m; SW= 1.4 ( 1.2-1.5)....
........................... S. monticolum
- IJ's body length = 849( 736-950)?m; Excretory pore= 62?m; Ratio c=10.4;
Oesophagous= 136?m (115-150)?m;SW= 1.1(1-1.3)
.........................S. feltiae
15. IJ's excretory pore average <25?m(14-22) ......................... S. neocurtillae
- IJ's excretory pore average> 25 ?m..........................16
16. IJ's with two prominent cephalic horns ........................17
- IJ's without 2 cephalic horns.................................18
17. IJ's body length 706?m; SW=1.0-2.0; Mucron present only in
2nd generation females but absent in other stages
.................................... S. ceratophorum
- IJ's body length 770?m; SW= 2.2-2.3; Mucron present in all the
adults excepting for 1st generation males........................ S. bicornutum
18. Mucron absent in adults of both sexes in both generations;
IJ's ratio c=12.6; Spicules= 83(73-91)?m.............................. S. karii
- Mucron absent in adults excepting for 2nd generation males;
IJ's Ratio c= 14; Spicules= 71(65-73)?m................................ S. oregonense
19. IJ's average tail < 85?m( 67-78); IJ's E% > 106?m (119-160)
............................................ 20
- IJ's average tail > 90?m(94-95); IJ's E% < 106?m (85-101)
.................................. 22
20. Ratio SW=1.4; Spicules= 58 (50-67)?m; IJ's E%=160....................S. cubanum
- Ratio SW = 2.0; Spicules= 72(77-84)?m; IJ's E% < 140......................... 21
21. IJs with excretory pore 76-86?m from anterior end; Spicule 84?m
with swollen tip; Males' D%= 93(88-102); Mucron present in
females of both generations but absent in males................ S. arenarium
- IJs with excretory pore 87-110?m; Spicules 77?m with notched tip;
Male's D%=70(60-78); Mucron absent in adults of both generations
In both the sexes ............................. S. glaseri
22. IJ's E%=101(88-108); Male's average D%= 77; Mucron
absent in adults of both sexes in both generations...................... S. puertoricense
- IJ's E%= 85 ( 77-109); Male's average D%=62; Mucron
present only in 1st generation females..........................S. longicaudatum
*Following 6 species not included in the key
1. S.asiaticum Anis et al., 2002
2. S. diaprepesi Nguyen and Duncan, 2002
3. S. loci Phan, Nguyen and Moens, 2001
4. S.pakistanense Shahina et al., 2001
5. S. sangi Phan, Nguyen and Moens, 2001a
6. S. thanhi Phan, Nguyen and Moens, 2001