Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2000
Publication Date: September 1, 2002
Citation: Handoo, Z.A. 2002. A key and compendium to the species of the heterodera avenae group (nematoda: heteroderidae). Journal of Nematology. 34(3):250-262.
Interpretive Summary: Nematodes are microscopic worms that cause an estimated ten billion dollars worth of crop loss in the United States each year. Among the most destructive nematodes are those called the avenae group of cyst nematodes; one of them, the cereal cyst nematode, is a major pest of cereals throughout the world. One problem with determining the potential extent of cyst nematode damage to crop plants is that the cyst nematodes present in an area can be identified only with extreme difficulty. Therefore, in the present study, specimens or pertinent literature of all described species of the avenae group were examined and evaluated. A new diagnostic aid or identification key of all these species was prepared, and a compendium providing the most important diagnostic characters of each species was developed as a useful supplement to the key. The identification key and compendium are significant because they provide the only accurate, all-inclusive guide to identification of the avenae group. This study will serve as a valuable asset for identifying nematodes and will be used by scientists, action agencies and extension agencies involved in nematode research and control.
A key based on cyst and juvenile characters is given for identification of 10 cyst forming nematode species of the avenae group. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. The characters most useful for separating species are the cyst characteristics (particularly shape, color, cyst wall pattern, fenestration, vulval slit length, and the structural differences of the cone top including presence or absence of bullae and underbridge), and those of second-stage juvenile morphology (particularly shape of stylet knobs, shape and length of tail and hyaline tail terminus, and number of lines or incisures in the lateral field). Photomicrographs of important morphological and diagnostic features are shown. A list of all valid species in the H. avenae group is given, and as defined in the paper this group is currently composed of 10 valid species.