First Report of Catenaria auxiliaris Parasitizing the Reniform Nematode Rotylenchulus reniformis on Cotton in Alabama

A new fungal parasite of the reniform nematode has been observed parasitizing nematode populations that have increased on cotton in a sandy loam field soil in the greenhouse. When enumerated, 46% of the stock reniform nematode population was colonized by this fungus. Egg, vermiform, and adult stages of the reniform nematode were observed with light microscopy and scanning electron micrography (SEM). The nematophagous fungus, Catenaria auxiliaries, was identified morphologically. There are no sequences on the GenBank to achieve a molecular identification. This nematophagous fungus has been previously reported on the beet cyst nematode in Europe (1,2); however, to our knowledge there are no reports of this fungus parasitizing the reniform nematode. In vermiform life stages of the nematode, rhizomycelium is observed in the initial phase of infection and is characterized by ovoid cells, 9.5 to 13.5 × 17.0 to 24.5 μm in diameter, separated by septa. Usually 10 to 15 ovoid cells lacking intercellular hyphal fil...