Aphelenchoides		Contents		Rev 11/20/2008
Foliar Nematodes		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Aphelenchoides Menu		Economic Importance		Damage
		Distribution		Management
Return to Aphelenchoididae Menu		Feeding		References
		Go to Nemaplex Home Page

Classification:

      Secernentea
       Tylenchida
        Aphelenchina
         Aphelenchoidea
          Aphelenchoididae
           Aphelenchoidinae
            Aphelenchoides

Allen provided a key to the four important species related to A. fragariae.  The key is useful in that it provides gross characters for separating the four species, but Sanwal's more detailed key would be necessary for more precise diagnosis.

1.  Head swollen, wider than neck, 4 lines in wing area............2

     Head not swollen, 2 lines in wing area................A. fragariae.

2.  Length of post-uterine branch 5 or more times body width...3

     Length of post-uterine branch less than 4 times body           width......                                                       ..........A. besseyi.

3.  Tail bluntly rounded, with a single ventral spine.....A. subtenuis.

    Tail terminus peg-like, with 4 small mucrons........A. ritzemabosi.

[From:  Allen, M.W. 1952. ]

Sanwal listed 33 species and provided a key in 1961 (Canadian J. Zool. 39:  143-148); there are more species described now.

Back to Top

Morphology and Anatomy:

Nematode is 0.5-1.2mm long, and slender.  

Nematodes in this genus have a large metacorpus. Dorsal overlap of the esophageal glands over the intestine.  They have a slender stylet with small, distinct knobs. Dorsal esophageal gland opens into lumen of esophagus in metacorpus, just anterior to the pump chamber. Subventral esophageal glands open into lumen of esophagus in metacorpus, posterior to the pump chamber.
Spermatheca with sperm in outstretched female gonad.
	The tail is mucronate (has terminal spikes) in some species.
Males have no bursa and have rose-thorn-shaped spicules.

Back to Top

Distribution:

Back to Top

Economic Importance:

Back to Top

Feeding:

Endoparasite in leaves, but also feeds ectoparasitically on leaf and flower buds in some plants.

Many species of Aphelenchoides feed on fungi.  Fungal-feeding species are common in soil and generally appear to have shorter stylets (< 8 µm) than plant-feeding species.

Ruess et al (2000) studied  the growth of Aphelenchoides sp. populations in vitro on 17 different fungal species.  Nematode populations developed on saprophytic (Agrocybe, Chaetomium) and especially on mycorrhizal fungi (Cenococcum, Hymenoscyphus, Laccaria).  They speculate that grazing by nematodes may influence the establishment and maintenance of mycorrhizal associations in the field. 

Mitosporic species, like Alternaria, Monocillium or Penicillium, were generally poor or non-hosts. This poor host status may be due to the release of toxic metabolites (e.g., antibiotics) and/or to morphological differences (e.g., forming of conidiophores) by the fungi. 

Food preference of Aphelenchoides sp. was tested in choice chamber experiments. Nematodes showed a marked preference for particular fungal species. They changed food source with time, indicating a "mixed diet" selection.  The attractiveness of a fungus was not necessarily correlated with its suitability as a host. 

Back to Top

Hosts:

Nematode genus has wide host-range and is usually associated with leaves and buds.

Back to Top

Life Cycle:

Back to Top

Damage:

Video Source: J.D. Eisenback, Nemapix.

Back to Top

Management:

Back to Top

References:

Allen, M.W. 1952.  Taxonomic status of the bud and leaf nematodes related to Aphelenchoides fragariae (Ritzema Bos, 1891).  Proc. Helminth. Soc. Wash., 19:108-120.

Ruess, L., E.J. Garcia Zapata, J. Dighton. 2000. Food preferences of a fungal-feeding Aphelenchoides species.  Nematology 2:223-230.

Sanwal 1961 (Canadian J. Zool. 39:  143-148)

Back to Top

For more information about nematodes, Go to Nemaplex Home Page.

Copyright © 1999 by Howard Ferris.
Revised: November 20, 2008