Nematodes Eelworms

Nematodes or eelworms are microsoopio roundworms which live in soil, decomposing organic matter, fresh or salt water, or on living host plants, fungi, insects and animals. Nematodes can survive up to six weeks without food and are unaffected by freezing. With eight billion nematodes in each acre of soil, they are one of the most numerous creatures on earth. 

If dried slowly, nematodes can change to a cryptobiotic or cyst state, thereby preserved for years until reactivated by water. In this cyst state, nematodes are also able to persist in high temperatures that would otherwise be lethal. 

Parthenogenesis, the ability for females to breed asexually without males, is common among nematodes and leads to very rapid population expansion. By this means, a single nematode can breed millions of descendants within a few weeks. Nematodes can also reproduce sexually, but not as rapidly. 

Nematodes present in mushroom culture can be classed into two basic types according t their feeding habits saprophagous and mycophagous. 

In bulk substrates such as compost or plain straw, nematodes can be found in great numbers. The high temperatures of Phase I conditioning would normally destroy them if it were not for the fact they migrate to the cooler outer shell of the compost pile. Phase II can eliminate nematodes but only if the entire compost is subjected to pasteurization temperatures. In a properly prepared and thoroughly pasteurized substrate, the mushroom mycelium consumes all free water and then feeds on the bacterial population. This creates a bacteriostatic environment , which effectively limits nematode growth capabilties. In an uneven substrate with overly wet and dry areas, however, the nematode s ability to breed increases. Wet areas are particularly suitable for 

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Microscopic nematode worms, invisible to the naked eye. Some attack plants, while others are beneficial, attacking slugs and larvae of weevils and other pests. See Potato cyst eelworm. 

Plant-parasitic nematodes, also called eelworms, are small transparent cylindrical organisms usually between 0.5 and 3.0 mm in length. By means of a stylet in the form of a... 

Nematodes, or eelworms, are abundant in nature, being widely distributed as parasites of vertebrate and invertebrate animals, and of plants. Free-living nematodes also constitute an important part of the soil fauna, being more numerous than any other animal of comparable size (Christie, 1959). Nielsen (1967) states that there are about 10,000 known species of Nematoda but of these only about 2,000 are soil inhabitants. These soil species are for the most part of microscopic or near-microscopic size, whereas the animal parasitic species are mostly visible to the naked eye. The average length of the kinds that occur in soil is about one millimeter. 

Unsegmented eelworms belong to a group of animals termed nematodes, which attack the roots of crop plants causing considerable damage. In order to achieve efficient control of nematodes, two types of nematicides have been used. 

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