Curly top is a serious problem in many irrigated crops in the semiarid areas in the western United States. The disease is caused by a complex of leafhopper-transmitted curtoviruses, one of which, Beet mild curly top virus (BMCTV), was previously found in chili pepper in Zacatecas and Aguascalientes, Mexico (3). During the past few years, sporadic symptoms similar to curly top disease were observed in jalapeño pepper in the south-central area of Chihuahua State. Symptomatic plants were scattered in otherwise healthy looking pepper stands and displayed stunting and yellowing. Affected leaves were brittle, showed upward curling, and a distinct green vein pattern with interveinal yellowing. In June and August of 2010, field surveys were conducted in Cordillera-Escuadra, Meoqui-Estacion Consuelo, Meoqui-Lomas del Consuelo, and Delicias-Presa Francisco I Madero. Ninety-four leaf samples were collected from symptomatic jalapeño pepper plants and subjected to ELISA and PCR testing for curly top. Of the 94 samples, 11 were found to be positive by triple-antibody sandwich-ELISA with polyclonal antibodies against curly top (2). To confirm the identification of curly top and type the specific curtovirus identified, four ELISA-positive samples were subjected to a PCR analysis using a virus-specific primer set for curtovirus typing designed by Chen et al. (1). All four samples tested produced a single 720-bp band with primers BSCTVv2688 and BGc396 (1) characteristic of the Beet severe curly top virus (BSCTV). These curly top-specific PCR amplicons were sequenced and found to be 99% similar to the BSCTV nucleotide sequence in the C1 gene region (GenBank Accession No. X97203); corresponding sequences were deposited in GenBank under Accession Nos. JF437870 to JF437873. To our knowledge, this is the first report of the curly top virus in the State of Chihuahua, demonstrating that curly top is established and common in jalapeño pepper here and will need surveillance in other vegetable crops under irrigation.
References: (1) L. F. Chen et al. Plant Dis. 94:99, 2010. (2) J. Durrin et al. Plant Dis. 94:972, 2010. (3) R. Velásquez-Valle et al. Plant Dis. 92:650, 2008.