Resumo

BOITO, G.T.  e  ORNAGHI, J.A.. Role of winter cereals and their management system in the population dynamics of Delphacodes kuscheli, the MRCV vector insect. Agriscientia [online]. 2008, vol.25, n.1, pp.17-26. ISSN 1668-298X.

The Mal de Río Cuarto is the most important disease in maize in Argentina. The virus belongs to the Genus Fijivirus (Reoviridae). It is transmitted in a persistent propagative manner by Delphacodes kuscheli Fennah (Hemíptera- Delphacidae). Several grain crops are virus reservoirs and insect vector hosts. The objective of this work was to study the role of grazed and non grazed oat, barley, wheat, rye and triticale in the population dynamics of Delphacodes kuscheli. The experimental plots were sown in the endemic MRC area under a strip design during the 1998, 1999 and 2000 seasons. Vector insect populations were evaluated weekly using a sweep net (100 net sweeps). The collected material was classified into nymphs and adults (macropters and brachypters). Results highlight the importance of crop management on vector population because grazed cereal winter crops show the highest vector insect number. Oat crop shows the largest number of vector insect, followed by wheat and barley. The peak occurrence of adult macropter population in oat is clearly different from that in the other cereals evaluated. The rate of population growth of nymphs and adult brachypters was more important in oat, showing no differences among the others crops.

Palavras-chave : Winter cereals; Management system; Epidemiology.

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