A Key to Commonly Occurring Nematophagous Fungi

 

Koon-Hui Wang, Robert McSorley

University of Florida, Department of Entomology and Nematology, P.O. Box 110620, Gainesville, FL 32611-0620, U.S.A.

(Last updated September 2003)

 

 

Preface

 

This key for nematophagous fungi is simplified from the key of Cooke and Godfreys (1963) with the focus on nematode-trapping fungi and endoparasitic fungi. Nomenclature for the Dactylella-Monacrosporium complex are updated according to Revision of predacious hyphomycetes in the Dactylella-Monocrosporium complex (Rubner, 1996). Many of the pictures attached are from the collection and publications from Dr. R. Esser, Society of Nematologists biocontrol slide set, as well as the authors’ collection. The authors recommend readers to use the original key for species identification and only use this key as a pictorial guidance.

 

KEY TO NEMATOPHAGOUS FUNGI

 

1. Endoparasitic fungi (mycelium in the life cycle predominantly inside nematode host)………. ………… 2

1. Predatory fungi (mycelium in the life cycle predominantly outside nematode host)… ………….………..13

2.Assimilative hyphae within host transformed into fertile hyphae, extended out of host slightly, producing adhesive cells or ingestive conidia………………………………………3

2.Vegetative hyphae within host transformed into sporangia producing zoospores, or producing conidia, zygospores or azygospores…………………………9

 

Endoparasitic Fungi with Adhesive Cells or Ingestive Spores

3. Hyphae aseptate………………………………………………………………………………………………………..

3. Hyphae septate………………………………………………………………………………………………………..4

4. Hyphae with clamp connection…………………………………………………………………5

4. Hyphae without clamp connection……………………………………………………………...7

       a. Nematoctonus

5. Hyphae bearing adhesive cells (knobs).

       a. Nematoctonus robustus Jones

       b. N. concurrens Drechs.

       c. N. haptocladus Drechs.

       d. N. campylosporus Drechs.

5. Hyphae lacking adhesive cells, but producing adhesive knobs on conidium………………….6

6. Chlamydospores produced

       a. Nematoctonus pachysporus Drechs.

       b. N. tylosporus Drechs.

6. Chlamydospores not produced

a. Nematoctonus leiosporus Drechs.

b. N. leptosporus Drechs.

7. Conidia borne on strigmata, no phialides

       a. Drechmeria coniospora (Drechs.) Gams & Jansson

7. Conidia borne on phialide….…………………………………………….……………………..8

8. Conidia adhesive

       a. Hirsutella rhossiliensis Minter & Brandy

       b. H. minnesotensis Chen, Liu, Chen

8.Conidia filiform

       a. Harposporium helicoides Drechs.

       b. H. oxycoracum Drechs.

       c. H. subuliforme Drechs.

8. Conidia arcuate

       a. H. anguillulae Lohde (Karling)

       b. H. liliputanum Dixon

       c. H. crassum Shepard

8. Conidia straight or slightly curved

       a. H. baculiforme Drechs.

       b. H. sicyodes Drechs.

8. Conidia pea-pod, barbed at one or both ends

       a. H. bysmatosporum Drechs.

       b. H. diceraeum Drechs.

(See Species of Harposporium spp.in Esser, 1992)

9. Vegetative hyphae within the host developed into conidiophores that pass out of host, producing conidia.

       a. Meristacrum asterospermum Drechs.

 

Endoparasites that Produce Encysting Spores

9. Vegetative hyphae within the host transformed into sporangia producing spores…….……...10

(See Fungi that utilize zoospores to parasitize nematodes by Esser and Schubert, 1983)

10 Sporangium (zoosporangium) producing motile zoospores…..……….……………………..11

10. Sporagium producing inmotile spores………………………..…….………………………..12

11. Zoospores uniflagellate, no zygospores, no resting spores.

       a. Catenaria anguillulae Sorokin

 (see Pathogenicity of selected nematodes by Catenaria anguillulae, Esser and Ridings, 1973)

       b. Rhizophydium sp.

11. Zoospores biflagellate, may form zygospres, produce resting spores.

       a. Lagenidium caudatum Barron

b. Myzocytium vermicola (Zopf) Fischer

       c. M. glutinosporum Barron

       d. M. humicola Barron & Percy

       e. Nematophthora gynophila Kerry & Crump

12. Spores globular or polyhedral with a lobed appendages.

       a. Haptoglossa heterospora Drechs.

12. Spores clavate.

       a. Protascus subuliformis Dangeard

 

Nematode-Trapping Fungi

13. Morphologically unmodified hyphae………………………………………………………...14

13. Morphologically modified hyphae forming traps……………………………………………17

14. Hyphae aseptate with yellow adhesive substances at contact…………………………….…15

14. Hyphae septate…...…………………………………………………………………………..16

 

Adhesive Mycelia

15. Produce conidia on simple conidiophore.

       a. Stylopage hadra Drechs.

       b. S. leiohypha Drechs.

       c. S. grandis Drechs.

15. Without conidia, but chlamydospores formed.

       a. Chlamydospores formed laterally: Cystopage lateralis Drechs.

       b. Chlamydospores formed intercalary: C. intercalaris Drechs.

       c. Chlamydospores on crooked branches or intercalary: C. cladospora Drechs.

16. Conidia bifurcate

       a. Triposporina aphanopaga Drechs.

16. Conidia furcated, trident-like.

       a. T.ridentaria implicans Drechs.

17. Hyphae aseptate, lateral branches bearing poorly differentiated adhesive knobs.

       a. Acaulopage pectospora Drechs.

17. Hyphae septate...……………………………………………………………………………..18

18. Hyphae forming adhesive branches, sometimeS forming simple 2-dimensional network; conidiophore simple, single terminal conidium.

 

Adhesive Branches

(see Fungi employing mucilaginous hyphal, sessile, or stalked globose cells to entrap nematodes by Esser and Schubert, 1982).

       a. Monacrosporium cionopagum (Drechs) Subram [Dactylella cionapaga Drechs]

Synonym:  M. gephyropagum (Drechs) Subram. [Dactylella gephyropaga Drechs.]

18. Hyphae forming stalked or sessile adhesive knobs..……………………………………….19

18. Hyphae forming stalked non-constricting rings, sometimes accompanied by stalked adhesive knobs………………………………………………………………………………………..21

18. Hyphae forming stalked constricting rings…………………………………………………22

18. Hyphae anastomosing to form 2 or 3 dimensional adhesive networks……………………..23

 

Adhesive Knobs

19. Conidiophore branched

       a. Arthrobotrys haptospora (Drechs.) Schenck, Kendr & Pramer [Dactylaria haptospora Drechs.]

       b. Monacrosporium haptotylum (Drechs.) Liu & Zhang [D. haptotyla Drechs.]

              Synonym: M. candidum (Nees.) Liu & Zhang; D. sclerohypha Drechs

       c. M. asthenopagum (Drechs.) Rubner [Dactylella asthenopaga Drechs.]

19. Conidiophore simple………………………………………………………………………..20

20. Adhesive knobs always sessile

       a. Monacrosporium phymatopagum (Drechs.) Subram. [Dactylella phymatopaga Drechs.]

20. Adhesive knobs sessile or short-stalked, often form short chains of adhesive cells.

       a. M. parvicolle (Drechs.) Cooke & Dickinson [Dactylella parvicollis Drechs.]

       b. M. lobatum (Dudd.) Rubner [Dactylella lobata Dudd.]

       c. M. robustum (McCulloch)

20. Adhesive knobs always stalked

       a. M. ellipsosporum (Preuss) Cooke & Dickinson [Dactylella ellipsospora (Preuss) Grove]

       b. M. mammillatum (Dixon) Cooke & Dickinson [D. mammillata Dixon]

 

Non-constricting Rings

21. Adhesive knobs not present.

       a. Monacrosporium leptosporum (Drechs.) Rubner [Dactylella leptospora Drechs.]

21. Adhesive knobs present, conidiophore simple.

       a. Monacrosporium lysipagum (Drechs.) Subram. [Dactylella lysipaga Drechs.]

21. Adhesive knobs present, conidiophore branched.

       a. Monacrosporium candidum (Nees) Liu & Zhang [Dactylaria candida (Nees) Sacc. Drechs.]

              Synonym: M. haptotylum (Drechs) Liu & Zhang

 

Constricting Rings

(See Fungi that entrap and assimilate nematodes by employing constricting rings by Esser and Schubert, 1991)

22. Conidia borne in a terminal cluster on conidiophore.

       a. Arthrobotrys anchonia Drechs.

       b. A. dactyloides Drechs.

       c. A. brochopaga (Drechs.) Schenck, Kendrick & Pramer [Dactylella brochopaga Drechs.]

       d. A. gracilis (Dudd.) Schenck, Kendrick, & Pramer [Dactylaria gracilis Dudd]

22. Conidium borne singly on a simple conidiophore.

       a. Monacrosporium polybrochum (Drechs.) Subram. [Trichothecium polybrochum Drechs.]

       b. Monacrosporium acrochaetum (Drechs.) Cooke [Dactylella acrochaeta Drechs.]

       c. M. doedycoides (Drechs.) Cooke & Dickinson [D. doedycoides Drechs.]

       e. M. stenobrochaum (Drech.) Subram. [D. stenobrocha Drechs.]

       f. M. bembicodes (Drech.) Subram [D. bembicodes Drechs.]

       g. M. turkmenicum (Sopronov) Cooke & Dickinson [D. turkmenica Sopronov]

       h. M. coelobrochum (Drechs) Subram. [D. coelobrocha (Drechs.) Subram.]

 

3-dimensional Networks

23. Conidia with one septum

       a. Arthrobotrys cystoporia (Dudd.) Mekht. [Trichothecium cystoporium Dudd.]

       b. Duddingtonia flagans (Dudd.) Cooke [T. flagrans Dudd.]

       c. T. pravicovi Soprunov

       d. T. globosporum var globosporum Soprunov

       e. T. globosporum var microsporum Soprunov

       f.  T. globosporum var roseum Soprunov

       g. Arthrobotrys arthrobotryoides (Berl.) Lindau Drechs.

       h. A. conoides Drechs.

       i. A. oligospora Fresenius

       j. A. superba Corda.

       k. A. longispora Soprunov

       l. A. oviformis Soprunov

       m. A. doliformis Soprunov

       n. A. kirghizica Soprunov

       o. A. cladodes var cladodes Drechs.

       p. A. cladodes var macroides Drechs.

       q. A. robusta Dudd.

       r. A. musiformis Drechs.

23. Conidia with more than one septum.

       a. Monacrosporium eudermatum (Drechs.) Subram [Dactylaria eudermata Drechs].

       b. M. psychrophilum (Drechs.) Cooke & Dickinson [Dactylaria psychrophila (Drechs) Subram.]

       c. M. megalosporum (Drechs) Subram. Dactylella megalospora Drechs.

       d. M. reticulatum (Peach) Cooke & Dickinson [Dactylella reticuluta Peach]

       e. M. thaumasium (Drechs.) de Hoog & Oorschot [Dactylaria thaumasia Drechs.]

       f. Arthrobotrys polycephala (Drechs.) Rifai [D. polycephala Drechs.]

g. A. pyriformis (Juniper) Schenck, Kendr. & Pramer [Dactylaria pyriformis Juniper]

       h. A. scaphoides (Peach) Schenck, Kendr. & Pramer [Dactylaria scaphoides Peach]

       i. M. gampsosporum (Drechs.) Rubner [Dactylaria gampsospora Drechs.]