Nematode diseases have increased greatly in economic importance in vegetable and ornamental bulb crops. Nematodes are important parasites of gladiolus, narcissus, tulip, onion, and garlic, and to a lesser extent on leek, spring onion, iris, hyacinth, and lily. The main nematode genera affecting bulb crops throughout the world are Ditylenchus, Heterodera, Longidorus, Meloidogyne, Paratylenchus, Pratylenchus and Paratrichodorus. Some of these nematodes are quarantined in various countries and regions due to their wide host range, potential for damage to economically important crops, or because their geographic ranges are restricted. Once established, eradication of these nematodes is almost impossible. Nematode species are often introduced into uninfested land on seeds or bulbs, and once introduced, they are difficult to control. Ditylenchus dipsaci has many attributes which make it particularly difficult to manage.
