APS Abstract of Presentation

Shoot blight and anthracnose of blackberries in Mexico is caused by Glomerella cingulata
A. REBOLLAR-ALVITER (2), H. V. Silva-Rojas (1), L. X. Zelaya-Molina (1)
(1) Colegio de Postgraduado/Produccion de Semillas, Montecillo, Mexico, 56230; (2) Universidad Autonoma Chapingo/Centro Regional Morelia, Morelia Michoacan, Mexico, 58170
Phytopathology 98:S131

Blackberry cultivated area in Mexico is near 6000 ha, and 80% of this area is located in Michoacan State. Shoot blight and anthracnose is a very common disease during the raining season, affecting seriously the production of this fruit. The main objectives of this research were to identify the causal agent of shoot blight and anthracnose, and to do in vitro testing of some commonly used fungicides for controlling this disease. Samples of blackberry plants showing shoot blight and anthracnose were recorded and used to do isolations on PDA medium. Pathogenicity test were conducted by spraying the shoots with a suspension of 10(^6) conidia/ml obtained from an isolate producing abundant sporulation. Inoculated shoots were incubated in a moist chamber for 48 h at room temperature. The first symptoms appeared three days post-inoculation on younger leaves, and six days later, the whole shoot was completely blighted. To identify the causal agent, DNA was extracted from mycelia of 11 isolates, and ITS region was amplified and sequenced using ITS5/NL4 primer pair. The phylogenetic analysis identified the isolates as Glomerella cingulata (Genbank accession numbers: EU358943-EU358953). In vitro fungicide tests showed good to excellent activity of captan, mancozeb, copper sulfate, copper oxychloride, phosphite and a sanitizing agent at commercial rates. These results report the presence of a new pathogen on blackberry in Mexico, and the activity of some fungicides for disease management.