Heterodera mani		Contents		Rev 07/29/2024
Ryegrass Cyst Nematode; Grass Cyst Nematode		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Heterodera Menu		Economic Importance		Damage
		Distribution		Management
Return to Heteroderidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Tylenchida
       Tylenchina
        Tylenchoidea
         Heteroderidae
          Heteroderinae

           Heterodera mani Mathews, 1971

A member of the Avenae group of Heterodera spp.

Synonyms:
    

Review general characteristics of the genus Heterodera.

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Morphology and Anatomy:

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Distribution:

Reported from Europe: Belgium, Estonia, France, Germany, Italy, The Netherlands, Slovakia, United Kingdom; Africa: South Africa; North America: United States (California, Washington)  and Tasmania(Subbotin et al., 2010; Subbotin et al., 2018; EPPO, 2021)

First reported from perennial ryegrass, Lolium perenne, in Northern Ireland by Mathews (1971). The first official California record was  in June 1980 from a collection made of miscellaneous roadside grasses. (Scheck, 2021).

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Economic Importance:

B-rated pest in California Nematode Pest Rating System. 

Althougfh recently found in Tasmania, further research is required to determine whether it affects the yield of perennial ryegrass (Jain et al. 2022; Stirling, 2023).

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Feeding:

Feeding site establishment and development typical of genus.
      

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Hosts:

The genus Heterodera has been divided into ninegroups. H. mani is in the Avenae group and is part of the H. avenae complex. (Subbotin et al., 2010; Handoo and Subbotin, 2018). The species of this group parasitize only monocotyledonous plants.

Molecular markers based on the internal transcribed spacer (ITS) region of the ribosomal RNA gene and, the cytochrome oxidase I gene can be used to differentiate species in this complex.

As of 2021, ten species in the H. avenae complex: H. arenaria, H. avenae, H. aucklandica, H. australis, H. filipjevi, H. mani, H. pratensis, H. riparia, H. sturhani, and H. ustinovi. Five species from this group are considered  pests of small grains and are collectively known as cereal cyst nematodes (CCN) (Smiley et al., 2017). The other species in the complex, including H. mani, parasitize grasses but not cereals, and are less important in agricultural production (Subbotin et al., 2018).

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Life Cycle:

Ecophysiological Parameters:

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Damage:

The diagnostic symptoms of cyst nematodes are usually the presence of cysts on the roots, the proliferation of roots, and shallow, bushy root systems. Heavily colonized young plants are stunted, and their lower leaves are often chlorotic, forming pale green patches in the field. Mature plants are also stunted and have a reduced number of tillers. Their roots are shallow and have a “bushy-knotted” appearance, without necrosis or brown lesions. Plants produce smaller heads with shriveled grain kernels (Smiley et al., 2017).

In Europe, Mowat (1974) reported that H. mani had little effect on the yield of perennial ryegrass in pot trials. However, in field trials with higher inoculum levels, Maas and Brinkman (1977) reported considerable damage to spring-sown perennial ryegrass with an obvious reduction in growth of perennial ryegrass at the second cut in May which coincided with a mass invasion of the roots by second-stage juveniles.

No damage has been reported specifically from this species in California; however, golf courses and sports fields report nematode feeding damage as an important problem.

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Management:

Host Plant Resistance, Non-hosts and Crop Rotation alternatives: