Effect of the nematophagous fungi Hirsutella rhossiliensis and Verticillium balanoides on stem nematode (Ditylenchus dipsaci) in white clover

1997 ◽  
Vol 26 (3) ◽  
pp. 142 ◽  
Author(s):  
F.S. Hay ◽  
L. Bateson
Keyword(s):  
White Clover ◽  
Nematophagous Fungi ◽  
Hirsutella Rhossiliensis ◽  
Ditylenchus Dipsaci

Observations on resistance in white clover (Trifolium repens L.) to the stem nematode (Ditylenchus dipsaci (Kühn) Filipjev)

1988 ◽  
Vol 110 (1) ◽  
pp. 145-154 ◽  
Author(s):  
R. Cook ◽  
D. R. Evans
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Significant Positive Correlation ◽  
Leaf Size ◽  
Nematode Reproduction ◽  
Long Period ◽  
Plant Collections ◽  
Ditylenchus Dipsaci ◽  
Trifolium Repens L ◽  
Selection For

SummaryThe expression of symptoms of stem nematode reproduction on a total of 53 white clovers (26 cultivars, 14 genepools and 13 introductions from plant collections) was studied in a series of field and glasshouse experiments. Seedlings or stolon-tip cuttings were inoculated with nematodes and the clovers classified by the proportion of plants which developed symptoms. Significant differences were found between varieties although in each test the majority was intermediate between more resistant and susceptible extremes. There was significant positive correlation between tests, in spite of different inoculation methods and different average levels of susceptibility. Very large-leaved cv. Aran was more resistant than most other clovers tested, and small-leaved cv. S. 184 was more susceptible. There was no general correlation of leaf size with reaction to stemnematode. Small-leaved cv. Pronitro was also resistant while several large-leaved cultivars were susceptible. In observations of plants exposed to nematodes over a long period, either by sequential inoculations or through perpetuating latent infections, apparently resistant plants eventually succumbed and supported nematode reproduction. It has not been determined whether this was because selection for virulence in the nematodes had occurred.

scholarly journals Enchytraeids and Nematophagous Fungi in Tomato Fields and Vineyards

1999 ◽  
Vol 89 (5) ◽  
pp. 398-406 ◽  
Author(s):  
B. A. Jaffee
Keyword(s):  
Heat Treatment ◽  
Fungal Growth ◽  
Mesh Size ◽  
Nematophagous Fungi ◽  
Agricultural Fields ◽  
Fine Mesh ◽  
Heat Treated ◽  
Initial Hypothesis ◽  
Hirsutella Rhossiliensis ◽  
Pvc Pipe

I tested the hypothesis that exclusion of enchytraeids and microarthropods in agricultural fields improves establishment of two nematophagous fungi. Soil was collected from three tomato fields and two vineyards and either heat-treated (2 h at 60°C) or not. Alginate pellets containing hyphae of the fungi Hirsutella rhossiliensis or Monacrosporium gephyropagum were added to the soil, which was packed into cages (PVC pipe, 80-cm3 volume) sealed with fine (20 μm) or coarse (480 μm) mesh. Cages were buried 22 cm deep in the same fields from which the soil had been collected. After 7 to 50 days, the cages were recovered and fungi and fauna quantified. Fine mesh largely excluded enchytraeids, collembolans, and mites but rarely affected fungus numbers. In contrast, heat treatment of soil rarely affected enchytraeids, collembolans, or mites but frequently increased fungus numbers, regardless of mesh size. The data are inconsistent with the initial hypothesis but are consistent with the idea that organisms narrower than 20 μm interfere with fungal growth from the pellets.

Effects of temperature on stem nematode (Ditylenchus dipsaci) infestation of white clover (Trifolium repens) swards

Nematology ◽  
1999 ◽  
Vol 1 (4) ◽  
pp. 415-420 ◽  
Author(s):  
Gwyn S. Griffith ◽  
Roger Cook ◽  
K. Anthony Mizen
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Daily Temperature ◽  
Lethal Temperature ◽  
Ditylenchus Dipsaci ◽  
Effects Of Temperature

Abstract Development of stem nematode (Ditylenchus dipsaci) infestations of white clover (Trifolium repens) in artificially established swards and transplanted turfs was monitored at field sites with different mean daily temperatures. In artificial swards the level of nematode infestation was inversely related to mean daily temperature. In transplanted turfs, nematodes caused a 46% reduction in white clover density over an 18-month period; the level of damage was not significantly affected by mean daily temperature although the proportion of clover stolons infested was higher at colder temperatures. Reductions in infestation levels at higher temperatures are probably the result of reduced survival in soil and the upper lethal temperature for nematodes being exceeded more frequently under warmer conditions. Influence de la temperature sur l'infestation, dans des pelouses, du trefle blanc (Trifolium repens) par le nematode des tiges (Ditylenchus dipsaci) - Le developpement de l'infestation du trefle blanc (Trifolium repens) par le nematode des tiges (Ditylenchus dipsaci) dans des pelouses artificielles ou des gazons transplantes a ete controlee, au champ, a differentes temperatures journalieres. Dans les pelouses artificielles, le niveau de l'infestation par le nematode est inversement proportionnel a la temperature journaliere moyenne. Dans le cas des gazons transplantes, et sur une periode de 18 mois, les nematodes reduisent de 46% la densite des trefles blancs; le niveau des degats n'est pas significativement affecte par la temperature moyenne journaliere quoique la proportion de stolons de trefle infestes soit plus elevee aux temperatures les plus basses. La diminution de l'infestation aux temperatures elevees est probablement due a une moindre survie du nematode dans le sol et au fait que les temperatures letales pour lui soient plus frequemment depassees dans des conditions de plus grande chaleur.

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