There is a general lack of awareness of nematodes among the general public. This can easily result in the unintentional importation of nematodes on ornamental plants. Growers who do not have nematode problems are often unaware of their existence. This can result in unintentional movement of nematodes in soil, irrigation water, on equipment and on planting stock. In spite of the use of methyl bromide for nursery fumigation, nursery personnel may think this is for weed control which they reason can be done by less expensive means. On farms, nurseries, and in government agencies, there is a continual turnover of personnel, and consequently there is a continuing need for education about the importance of prevention in the management of nematodes.
In California, nematologists have long cautioned that nematodes can be spread in irrigation water
The best information on the ability of nematodes to be carried in irrigation water comes from work conducted in the state of Washington. These studies demonstrated that irrigation canals transported a dozen different genera of plant parasitic nematodes. They also showed via greenhouse trials that many of these nematodes were viable. Conclusions were that growers applying an acre inch of water were also applying several million parasitic nematodes.
One relatively inexpensive method to combat this problem would be to first pump irrigation water into settling ponds, allow nematodes to settle which should only require a few minutes, and then draw water off the top for irrigation.
Other potential methods for spreading nematodes which have not been intensively studied include wind , birds, and other animals. It has been demonstrated, for example, that cysts of the sugarbeet cyst nematode can pass through the digestive system of cattle and retain viability.
Manure should be properly composted before using so that it will reach temperatures lethal to nematodes. Also keep in mind that the soil beneath a pile of manure may also be infested with nematodes. Don't be greedy, take the manure but leave the soil behind.
The frequency with which growers contact nematologists after planting rootstocks with galls, lesions, or other root abnormalities, indicates that checking for nematodes before rather than after planting needs to be stressed. Typically there is a time factor involved in that planting crews are on site or already in progress when the symptoms are discovered. If planting must proceed, then at least some stock should be retained unplanted and that has not come in contact with the grower's soil if the source of a potential infestation is to be determined.
Eradication of plant parasitic nematodes from small plots of land is possible with use of heat or intensive soil fumigation. Under normal circumstances, for acres of land, eradication would be prohibitively expensive. Successful attempts to erradicate nematodes on this scale are rare, or perhaps even nonexistent.