KEY FOR IDENTIFICATION OF STEINERNEMA SPP. BASED ON SEM OBSERVATION OF SPICULES AND GUBERNACULA

  IJ body length more than 1,000 micrometers (um):

2- Spicule tip with a distinct aperture on ventral side, spicule
shaft long (FIG. SEM).... S. glaseri (Nguyen & Smart, 1995)
Spicule tip without a distinct aperture, spicule shaft
short or indistinct ....................................3

3- Spicule tip curved ventrally (FIG. SEM) .......S. puertoricense
Spicule tip not curved ventrally.........................4

4- Spicule blade reduced suddenly to form a tip with flattenned
terminus (FIG. SEM)............................ S. longicaudum
Spicule blade reduced gradually to form a bluntly rounded
tip (FIG. SEM).. S. cubanum

IJ body length between 800 and 1,000 um:

1- Spicule head short, length/width about 1 (FIG. SEM).... S. kraussei
Spicule head elongate, length/width mor than 1.5 ........2

2- Lateral lobe well curved dorsally, spicule tip bluntly
rounded (FIG. SEM).................................. S. feltiae
Lateral lobe not curved dorsally, spicule tip with a prominent
depression on ventral side (FIG. SEM).... S. neocurtillae (Nguyen & Smart, 1992a)

IJ body length between 600 and 800 um:

 1- Spicule long and wide, SL/SW averaging 4.2 (3.8-4.5), rostrum
prominent (FIG. SEM).............................S. intermedium
Spicule not so long and wide, SL/SW averaging 5.4 (4.9-5.8),
rostrum not so prominent ..............................2

2- Cuneus of gubernaculum arrowhead-shaped, spicule head with
ventral projection, wider than long (FIG. SEM)......S. bicornutum
Cuneus of gubernaculum needle-shaped or Y-shaped, spicule head
without ventralprojection, longer than wide .......3

3- Spicule sickle-shaped, spicule tip almost pointed; in ventral
view, gubernaculum neck almost as wide as posterior corpus
(FIG. SEM)........................................S. riobrave
Spicule not sickle-shaped, spicule tip blunt, in ventral view,
gubernaculum tapering gradually anteriorly to a narrow neck
(FIG. SEM)....................................S. affine

IJ body length less than 600 um:

1- Spicule short, wide, SL/SW averaging 3.9 (3.6-4.25), spicule
tip usually slightly curved dorsally; in ventral view, cuneus barely
seen (FIG. SEM)..................................S. kushidai
Spicule long, thin, SL/SW averaging 5.4 (4.7-6.6), spicule tip not curved
dorsally, in ventral view, cuneus prominent .........2

2- Spicule with long, prominent shaft, spicule head directed dorsally,
in ventral view, gubernaculun enlarging gradually to form posterior
corpus (FIG. SEM).... S. scapterisci (Nguyen & Smart, 1990, 1992)
Spicule, with short shaft, spicule head directed ventrally, in ventral view,
gubernaculum enlarging abruptly to form posterior corpus
(FIG. SEM)...................................S.carpocapsae

General shape: size, relative curvature, and ratio SL/SW.
Spicule head: elongate, longer than wide, wider than long, ventrally projected.
Shaft: relative length,prominent or indistinct.
Spicule blade: curvature (curved evenly to both ends, well curved anteriorly, posterior part slightly curved or almost straight).
Lateral lobe of blade: extent of tapering (anteriorly tapering  to a point, not tapering,extended to shaft and head region), curvature.
Ventral lobe of blade: enlargement (enlarged anteriorly, dorsally, ventrally, not enlarged anteriorly).
Velum: presence or absence, appearance.
Spicule tip: curved ventrally, dorsally, with a notch, aperture present, narrowed suddenly, flattened or bluntly pointed terminus.

Gubernaculum

Ratio L/W in ventral view, enlarged posteriorly abruptly or gradually.
Cuneus length and shape: needle-shaped, Y-shaped, V-shaped, arrowhead-shaped, reaching posterior end or not.
Wings of corpus: expanded laterally or smooth.