Alternate hosts of Iris yellow spot virus and trips on onion crops in Morelos and Michoacan, Mexico

Abstract

The main goal of this research was to identify alternate hosts of Iris yellow spot virus (IYSV) and to establish the range of hosts of the putative vector(s) in onion (Allium cepa) producing regions of Morelos and Michoacan, Mexico. In 10 localities of both states, onion crops and weeds were sampled in the presence and absence of the crop. Onion plants were analyzed by RT-PCR and the weeds by DAS-ELISA. The weeds were identified at species level, the thrips collected from weeds were established colony for identification by PCR, with specific primers that amplify a segment of the cytochrome oxidase I (COI) gene. A total of 295 weeds grouped in 56 species (23 families) were analyzed and identified. All the weeds were negative for IYSV. Thrips were detected on 75 weeds grouped in 17 species. Thirty-three thrips populations were analyzed (22 from Morelos and 11 from Michoacan). Sequencing indicated identity with Thrips tabaci with a homology greater than 97 %. Weeds Ricinus communis and Acalypha ostryifolia were found with high number of T. tabaci. In onion, the presence of IYSV was confirmed with RT-PCR in the ten field plots sampled. This is the first report of IYSV in Michoacan state.