Morphometrical and host range studies of Nacobbus aberrans in Argentina

DOUCET, M.E; LAX, P.

Congreso; Second International Congress of Tropical Nematology; 2009

Since N. aberrans was first detected in Tafí del Valle (province of Tucumán) in 1977 it has been recorded in several other localities of the country where climatic and edaphic, conditions and plant cover are very different. Morphological, morphometrical and genetic analysis as well as studies of the host-parasite relationships were conducted in different Argentine populations of the nematode. The data obtained indicate the existance of populations with particular characteristics. On the basis of the morphometry of different stages of the nematode life cycle (second-stage juveniles, immature females, and males) two populations from the Andean regions were clearly differentiated from other 11 populations from the rest of the country. Also, the most variable characters between populations as well as the most stable ones were defined. Considering the groups or races previously defined for N. aberrans (sugarbeet, potato, and bean group) differential host range was examined in 7 populations of different geographical origin. Each population showed preference for certain plants. Four of them were identified as the sugarbeet group (populations infecting sugarbeet, pepper and tomato but not potato) whereas it was not possible to assign the remaining populations to any of those groups. Overall, the research conducted does not allow us to draw general conclusions so far, but shows trends that need to be more deeply analyzed. The genus Nacobbus, of unquestionable importance in the Neartic and Neotropical regions, continues to be represented by a group of biological entities of possibly different agricultural importance whose significance needs to be determined.