Globisporangium ultimum (Trow) Uzuhashi, Tojo & Kakish. 2010

It commonly occurs throughout New Zealand associated wide damping-off of seedlings in nursery rows and in newly sown crops. It may be controlled by seed dusting prior to sowing. Soil drenching with an organic fungicide such as captan may be used if damping-off due to Pythium develops in seed pans in nurseries. Copper fungicides may be used-but with caution, as with some seedlings it gives serious root burn. Brien (1940b) associated it with a storage rot of potatoes known as "leak", where it may be of considerable economic importance.

Eggertson, Quinn A.; Rintoul, Tara L.; Lévesque, C. André 2023: Resolving the Globisporangium ultimum ( Pythium ultimum ) species complex . Mycologia 115(6): 768-786.

Globisporangium ultimum (Trow) Uzuhashi, Tojo & Kakish. 2010

Notes

Based on the fulfillment of reciprocal monophyly andobserved genealogical concordance under the genealogical concordance phylogenetic speciesrecognition, we determined that the Globisporangium ultimum species complex is composed offour genetically distinct species: Globisporangium ultimum, Globisporangium sporangiiferum,Globisporangium solveigiae, and Globisporangium bothae.

Aside from cardinal temperatures,we were unable to find any other significant morpholo-gical, physiological, pathological, geographic, or hostpreference that would distinguish between these fournewly identified species. The described morphologicalcharacteristics and plates from Trow (1901), Drechsler(1960), and Van der Plaats-Niterink (1981) remain useful in broadly describing the morphology of this complex, even if they cannot be used diagnostically todifferentiate the four species.

Gadgil, P.D. (in association with Dick, M.A.; Hood, I.A.; Pennycook, S.R.) 2005: Fungi on trees and shrubs in New Zealand. Fungi of New Zealand. 4. Fungal Diversity Press.

Pythium ultimum Trow 1901

Description

Type: Radicicolous Fungi; Description: Colonies on corn meal agar with cottony white aerial mycelium, main hyphae up to 11 μm wide. Sporangia terminal or intercalary, globose to subglobose, 10–30 μm in diameter. Oogonia terminal, globose, 19–27 μm in diameter, smooth. Antheridia 1–2 per oogonium, sessile, arising close to the apex of the oogonial stalk. Oospores aplerotic, 14–22 μm in diameter.

Distribution

Distribution: Northland, Auckland, Bay of Plenty, Rangitikei, Wanganui, Wellington, Gisborne, Hawkes Bay, Wairarapa, Marlborough, Mid Canterbury, South Canterbury, Dunedin.; 1st Record: Brien & Dingley (1953).

Notes

Pathogenicity

Significance: A common and widespread cause of damping-off and root rot in seedlings. Reported to be highly pathogenic to roots of vegetable seedlings (Robertson 1976). In a survey of forest nursery diseases it was the most commonly found pathogen, causing periodic severe root rot in Larix decidua, Pinus nigra subsp. laricio, P. radiata, and Pseudotsuga menziesii (Bassett 1961).; Host(s): Acacia leprosa, Agathis australis, Araucaria heterophylla, Chamaecyparis lawsoniana, Citrus sp., Correa ×harrisii, Cupressus lusitanica, Dodonaea viscosa, Goodia lotifolia, Humulus lupulus, Larix decidua, Malus ×domestica, Persea americana, Picea sitchensis, Pinus nigra subsp. laricio, P. radiata, Pseudotsuga menziesii, Vitis vinifera.

Taxonomic concepts

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Globisporangium ultimum (Trow) Uzuhashi, Tojo & Kakish. 2010

Globisporangium ultimum (Trow) Uzuhashi, Tojo & Kakish.

Eggertson, Quinn A.; Rintoul, Tara L.; Lévesque, C. André (2023)