Nematode Pests of Horticultural Crops and their Management (1+1)

Exercise 9

Practical - 9

Exercise: Morphology of a Typical Plant Parasitic Nematode.
(Please place the Figures t proper places and give them numbers, put Figure numbers in the test also)
Objectives:

1. To distinguish plant parasitic forms from free living forms.
2. To differentiate males, females and juveniles.
3. To study easily visible, important morphological characters of body wall, digestive systemand reproductive system.

Observations:

• Observation of nematode specimens (in permanent mounts) under different magnifications of a compound microscope and observe the following characters.

Fig. 9.1 Gross morphology of a plant parasitic female nematode Fig. 9.2 Gross morphology of a plant parasitic male nematode

• Body shape- vermiform, sausage shaped, reniform, saccate, subspherical or any other shape.
• Dorsal, ventral and lateral sides
• Openings of various systems like anus (digestive system opening in female), excretory pore and its location (secretory excretory system), vulva (reproductive system of female)/ cloacal aperture(common opening of digestive and reproductive system in males)

Fig. 9.3 General body shape and location of various openings in nematodes

• Digestive system: stylet in the anterior region, oesophagus tripartite(comprising of anterior slender procorpus, highly muscular valvulated metacorpus (median bulb), narrow isthmus and a terminal/ overlapping basal bulb).

Fig. 9.4 Stoma of free living and plant parasitic nematodes and Fig. 9.5 Stomodeum of a plant parasitic nematode

• Female Reproductive system: genital tract whether one or two(monodelphic/didlphic) and their orientation to classify it in to (prodelphic/ opisthdelphic/amphidelphic), location of vulva with respect to body (%).
• Male Reproductive system: Number of testis (monarchic/diorchic), spicule for its shape, placement of gubernaculum and bursa(absent/present,leptoderan/peloderan).

Fig. 9.6 Female Reproductive system

Fig. 9.7 Male Reproductive system

General differences between juveniles, female and male nematodes:

Juvenile of nematode	Female nematode	Male nematode
Tail not arcuate	Tail not arcuate	Tail arcuate due to presence of sclerotized spicules
Opening of reproductive system not developed	Two separate openings foe digestive system(anus) and reproductive system (vulva)	Common opening for the two systems referred as cloacal aperture
Posterior region of the body is devoid of spicules, gubernaculm and bursa	Posterior region of the body is devoid of spicules, gubernaculm and bursa	Spicules and gubernaculums present, bursa may or may not be present