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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Mycology and Nematology Genetic Diversity and Biology Laboratory » Research » Publications at this Location » Publication #336542
Title: General Morphology

Author
item BALDWIN, JAMES - University Of California
item Handoo, Zafar

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 2/10/2017
Publication Date: 4/30/2018
Citation: Baldwin, J.G., Handoo, Z.A. 2018. General Morphology. In: Perry, R.N., Moens, M. and Jones, J.T. editors: Cyst Nematodes. Wallingford, Oxfordshire, UK: CABI. p. 337-364.

Interpretive Summary:

Technical Abstract: Within the Tylenchomorpha, including most plant-parasitic nematodes, cyst nematodes (Heteroderinae) are morphologically distinctive among Hoplolaimidae, consistent with adaptations for sedentary parasitism and the capacity for dormancy, i.e. suspended development. Cyst nematodes represent a large group of plant parasites comprising 119 species presently included in eight genera: Heterodera, Globodera, Punctodera, Cactodera, Dolichodera, Betulodera, Paradolichodera, and Vittatidera. They can reduce crop yield worldwide, and methods for their identification are often difficult to implement. Their morphology is the basis for identification and systematics. The light microscope (LM), the scanning electron microscope (SEM) and transmission electron microscopes (TEM) have been useful in revealing details and providing a sounder basis for identification. Several life stages are important and useful in both morphology and identification of the cyst nematodes around the world associated with economically important crops. This review summarizes the diagnostic morphological features important in identification and function of species in the above eight genera. Features include the morphology of all the life cycle stages (eggs and embryo, juveniles J2-J4, males, females, cysts- their transformation, surface structures and cones), information on their body wall (external SEM), and details of their nervous, digestive, secretory/excretory and reproductive systems. Drawings and images of important diagnostic characters of all the life stages (females, males, and juveniles) illustrating these key features are given. In addition, a detailed historical background and information on various techniques including LM, SEM and TEM used for species identification, are discussed. We also provide details on the minimum standards for species descriptions, conclusions and future prospects in cyst nematode taxonomy and diagnostics.