Resumo

ALMEYDA-LEON, Isidro Humberto; SANCHEZ-SALAS, José Alfredo  e  GARZON-TIZNADO, José Antonio. Vectors causal of potato purple top in Coahuila and Nuevo Leon, Mexico. Agric. Téc. Méx [online]. 2008, vol.34, n.2, pp.141-150. ISSN 0568-2517.

Potato crop production in the northeast of Mexico is affected by a complex of insect pests, where the most important insects are those that are vectors of virus and phytoplasms. The objective of this study was to examine the different insect species associated with potato crop and weeds in the region and determine the species with potential to transmit the phytoplasm causing potato purple top. The study was conducted from december of 2003 to august of 2004, in six sites: three in the state of Coahuila (El Tunal, Emiliano Zapata and Huachichil) and three in the state of Nuevo León (San Rafael, Cristal and Raíces). In the six sites there were collections during both years of insects, potato plants with typical symptoms of phytoplasm infection and weed plants growing around the potato crop field. In order to determine presence of the potato purple top phytoplasms, all the collections were analysed in laboratory through the technique Nested-Polymerase Chain Reaction (Nested-PCR), using the primers P1/P7 and R16mF2/R16MR1. The insect species that showed high populations were: the psyllids Bactericerca cockerelli and Heteropsylla texana, as well as the leafhoppers Aceratagallia spp. and Empoasca spp. The association of H. texana with the potato crop in the northeast of Mexico is considered as a new record. B. cockerelli was the most abundant species in all the experimental sites; furthermore, according with the results from Nested-PCR, this insect had the highest association with the potato purple top phytoplasm (52%). The pathogen was also found in the insects H. texana, Aceratagallia spp. and Empoasca spp., and in plants of potato, wild sunflower and correhuela. These results, to point at B. cockerelli how the vector principal possible of potato purple top phytoplasm in the study region.

Palavras-chave : Aceratagallia spp.; Bactericera cockerelli (Sule); Convolvulus arvensis L.; Empoasca spp.; Helianthus annuus L.; Heteropsylla texana (Crawford).

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