PRESENCE OF BCMV AND BCMNV IN FIVE DRY BEAN-PRODUCING STATES IN MEXICO.

Abstract

A survey was conducted to assess the frequency of BCMV and BCMNV in five of the main dry bean producing states in Mexico during the spring-summer 2009 and fall-winter growing seasons 2009-2010. States included in the survey were Nayarit, Sinaloa and Sonora in the pacific west coast, Veracruz in the gulf coast and Guanajuato in central Mexico. A total of 338 samples were collected and analyzed by RT-PCR with specific primers for each viral species.  Forty-four samples (13%) gave positive reaction for BCMV, 70 (21%) for BCMNV and 30 (9%) were positive for both viral species, 164 (48%) were negative for both viruses and 30 (9%) could not yet be defined. As for cultivars, Azufrado Higuera (Nueva Granada race) grown at Sinaloa showed the highest frequency (33%) of BCMV, whereas Negro Jamapa (Mesoamericana race) from Nayarit displayed highest frequency (50%) of BCMNV. In these two states the percentage of positive samples for either viral species was 80%. In addition, in cultivar Negro Jamapa mixed infections of both viruses were detected. Results point out a high risk of viral infection with seed movement across states, particularly since both viral species are seed transmitted and in the states at the pacific west coast, large seed lots are produced during the fall-winter season.