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

General Characters of Plant Parasitic Nematodes Resource (Contd..)

6. Musculature consists of smooth longitudinal muscle cells located between the hypodermal chords and are directly connected to longitudinal nerves. Circulatory muscles are absent.
7. Digestive, reproductive, nervous and excretory systems are present. Well defined respiratory and circulatory organs are absent.
8. The digestive system consists of a feeding apparatus, pharynx (oesophagus), intestine and rectum. Pharynx in all tylenchids is tripartite but in plant parasitic dorylaimids it is bipartite. At the junction of pharynx and intestine, a pharyngeo-intestinal valve (cardia) is present that ensures unidirectional flow of food.
9. They are usually dioecious with tubular reproductive organs.One or two gonads may be present
10. The nervous system consists of a circum-oesophageal nerve ring and longitudinal nerves which innervate all body parts. In addition, transverse nerves are also present connecting the longitudinal nerves.
11. The secretory-excretory system is primitive and consists of primitive single ventral gland cell (renette) in adenophoreans but consists of two lateral excretory canals joined to each other by transverse canals in secernenteans. It lacks proto-nephridial cilia or meta-nephridial flame cells.
12. They do not have any specialized structures for locomotion.

Fig. 3.3 Typical plant parasitic female and male nematodes, Photo courtsey: G F Schuman, NemaPix