TABLE CONTENTS

associated with peels for five minutes was effective but judged to be unacceptable to the
industry. Heating potato peels and associated water to 60 ºC or above for one minute or
longer was found to be an effective destruction protocol. Submersing whole tubers in water
at 80 ºC for a minimum of three minutes before peeling was a reliable destruction protocol
that would prevent escape of living CRKN through the peeling process.
Variability of the Reproductive Capacity of Nacobbus aberrans Populations
from Argentina on the Pepper Cultivar ‘California Wonder’
Lax, P. (1), M. E. Doucet (1), N. Coronel (2), O. Luque (3), N. Rojas (4), D. Ramos (5) & J.
Muzaber (5)
(1) Centro de Zoología Aplicada, Universidad Nacional de Córdoba, C.C. 122, 5000, Córdoba, Argentina; (2)
Estación Exp. Agroindustrial Obispo Colombres, Tucumán, Argentina; (3) Universidad Nacional de Catamarca,
Argentina; (4) Dirección de Extensión Rural del Ministerio de Producción, Catamarca, Argentina; (5)
Universidad Nacional de Río Cuarto, Argentina; (6) INTA La Consulta, Mendoza, Argentina.
Reproduction of seven Argentinean populations of N. aberrans on the pepper (Capsicum
annuum) cultivar ‘California wonder’ was evaluated. Nematodes were from different
localities of origin: Coronel Baigorria and Río Cuarto (province of Córdoba), Lisandro
Olmos (Buenos Aires), El Pucará del Aconquija (Catamarca), Tunuyán (Mendoza), Lules and
Tafí del Valle (Tucumán). All the populations were collected from soils cultivated with
horticultural crops, except for the first one, which was naturally associated with a weed
(Chenopodium album). The experiment was conducted in greenhouse conditions at a mean
temperature of 21 °C; six replications per population were performed. One hundred active
second-stage juveniles were inoculated per plant at planting. After 90 days, the Reproduction
Factor (RF=final density/initial density) was calculated for each population. All the
populations reproduced on pepper. However, three significantly different groups of
populations were distinguished: a) Coronel Baigorria, Lules, El Pucará del Aconquija and
Tafí del Valle (with RF ranging between 1.6-6.2); b) Río Cuarto and Lisandro Olmos
(RF=25.1-31.4); c) Tunuyán (RF=47.7). The variability detected in the reproductive capacity
of N. aberrans on a single host is useful for the formulation of alternative strategies to
manage this nematode using resistant cultivars.
Biogeography of the False Root-knot Nematode (Nacobbus spp.) and its
Major Crop Hosts
Manzanilla-López, R.H.
Nematode-Interactions Unit, Rothamsted Research. Harpenden, Herts AL5 2JQ, United Kingdom
Spatial separation of populations is one of the reasons for the variation in biography of this
nematode. Such variation is detected in plant parasitic nematodes over both great and
relatively small distances. Different organisms with the same ecological requirements can be
sympatric only if the environment they inhabit is heterogeneous. This heterogeneity may be
spatial or temporal but can also be provided by host plants. Nacobbus spp. are endemic to the
American continent and distributed along two biogeographical regions (Palearctic and
Nearctic). These regions are centres of origin of crops, including, amongst others, potato
(Solanum spp.), tomato (Lycopersicon spp.), chilli pepper (Capsicum spp.) and beans
(Phaseolus spp.) that were domesticated by ancient American civilizations in highly
5 th International Congress of Nematology, 2008 205