Epidemiology and distributional patterns of Meloidogyne (Nematoda: Meloidogynidae) in a monocropping system

P. Flores-Romero, G. Esparrago, A. Navas

Abstract


Epidemiological incidence of root-knot nematodes (Meloidogyne spp.) is not well known in the Iberian Peninsula. The apomictic Meloiodogyne arenaria, together with M. javanica and M. incognita, are responsible for major crops losses in this region. In the area of La Vera (Extremadura), where agricultural systems are more or less limited to monocropping with tobacco, M. arenaria is predominant (> 95% of samples). As an epidemiological evaluation, three fields naturally infested with M. arenaria populations were used to assess resistant and susceptible tobacco genotypes under natural conditions. Also, a distributional pattern approach of different M. arenaria multilocus enzyme electrophoresis (MLEE) variants was carried out in this area. Results showed a highly significant differential interaction of locality × variety × time (P < 0.000), as well as revealing considerable inter-population genetic variability of these pathogens. Distributional pattern analysis of 18 different MLEE variants revealed that geographic structure is lacking in the area of study. Consequently, the potential of management strategies based on the employment of resistant varieties is considered highly limited. An epidemiological zoning based on similarity groups is proposed as a starting point for the development of control programmes for these pathogens in the high-risk infested areas.

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