Fluctuación poblacional de cicadélidos positivos a fitoplasma asociado a punta morada en maleza aledaña a cultivo de Papa, en Arteaga, Coah., México

Abstract

Leafhoppers (Cicadellidae) are vector insects that may transmit up to 40 different viruses belonging to the Rhabdoviridae and Reoviridae families. The main vector of the potato purple top is the leafhopper Macrosteles fascifrons (Hemiptera: Cicadellidae) along with other leafhoppers. In the important potato region of Coahuila Nuevo Leon, producers don’t even know that Cicadellidae species are present, and also ignore some facts about this presence like population fluctuation, and in what weed species can they be found. Taking all this into account the objectives of this assay were expressed as: a) to detect species of Cicadellidae positive to phytoplasmas associated to the potato purple top, in weeds bordering the commercial potato fields, b) to determine the popula tion fluctuation of Cicadellidae positive to phytoplasmas associated to the potato purple top and c) to determine what weed species bordering the potato fields are positive to phytoplasmas. Samplings of leafhoppers and weeds were performed every week from January to December 2004 in Huachichil, Arteaga, Coah., Mexico. In order to detect phytoplasma, extractions of DNA of each one of the collected Cicadellidae species and weeds were made and PCR tests were realized. Fifty three different Cicadellidae species were collected, and phytoplasma was detected in Macrosteles fascifrons, Empoasca fabae, Oncometopia nigricans and one non identified species. The highest populations of adults of Cicadellidae altogether, were observed from November to February. Solely species of weeds: Flourensia cernua (Asteraceae), Parthenium incanum (Asteraceae), Prunus cercocarpifolia (Rosaceae) and Reseda luteola (Resedaceae), from the total of the 22 where Cicadellidae adults were found, were positive to phytoplasma.