Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
Phylum: Nematoda
Common name: Leaf Eelworm, Eelworm.
These tiny eelworms are about one to two millimetres long just visible against a dark background. There are thousands of eelworms (nematodes) species worldwide, a small proportion are plant parasites attacking roots, bulbs, corms, leaves, stems and buds. Plants most susceptible to leaf eelworm infections include ferns all varieties of African violet, chrysanthemums and buddleia shrubs. Eelworm infestation becomes apparent during the late summer season and autumn.
The symptoms of feeding eelworms are discolouration or distortion of tissues which may kill affected tissues or whole plants. Discoloured angular blotches on leaves are characteristically contained within the patterns of the veins.
Leaf eelworms infestations may be confirmed by crush the leaves and put them into a glass filled with clean water. If there are any live eelworms, they will start surfacing in the container in about 30 minutes. Some eelworms might sink to the bottom of the glass. This test is not exact and is only useful in detecting developed, mature eelworms.
Most plant-parasitic species under a microscope resemble eels with blunt heads and a mouth-spear.
[1]
The top surface of an infected fern[2]
An infected fern leaves undersurface.