English name: False Columbia Root-knot Nematode
Nordic names: Rodgallenematod (DK), Äkämäankeroiset (FI), Rotgallnematod (NO), Rotgallnematod (SE)
Major host plants
The only recorded natural host is potato (Solanum tuberosum). However, host-range tests in the glasshouse and field indicate that M. fallax can parasitize a wide range of other plant species. The experimental host range of M. fallax mostly overlaps that of M. chitwoodi.
Symptoms are very similar to those caused by M. chitwoodi; above ground symptoms are often hard to differentiate and infested roots often do not show the galling which is typical of other Meloidogyne species. Infested potato tubers may have small raised swellings on their surface. Adult females are visible just below the surface; when alive they appear as glistening, white, pear-shaped bodies surrounded by a brownish layer of host tissue. As the female matures and dies, the egg-filled sac becomes dark-brown with age. In general, it appears that M. fallax can cause more severe symptoms than M. chitwoodi.
A map can be downloaded from EPPO's website. See instructions here.
The life cycle of M. fallax and M. chitwoodi are, in general, the same.
Similar to M. chitwoodi, where transport of infested host plants are the main pathway.
Detection and inspection
Detection and inspection methods are similar to those for M. chitwoodi. The presence of M. fallax in infested soil can be determined by sampling and extraction of the second-stage juveniles. External symptoms on tubers are obvious in the case of heavy infestations but, where nematode numbers are low or in the early stages of infection, such symptoms are not obvious. Storage of lightly infested tubers may lead to the development of obvious external symptoms.
Pest status and importance
At present there is no direct information available to show the extent of economic damage caused by M. fallax. However, in the Netherlands, M. fallax is a pest of economic importance on potatoes, oyster plant (black salsify; Scorzonera hispancia) and carrots like M. chitwoodi.
Source of information
See further information here:
Author: Christiane Scheel
Editor: Elise T. Yamamoto Buch