Web blight (Thanatephorus cucumeris): a new disease on leaves of okra plants

Luadir Gasparotto, Cristiaini Kano, Paulo Ceresini, José Pereira, Marinice Cardoso, Danilo Pereira, Vanina Castroagudín
2018 Arquivos do Instituto Biológico  
ABSTRACT: In an experiment on organic production of okra (Abelmoschus esculentus (L.) Moench) that was carried out from September 2013 to January 2014, in Manaus, Amazonas state, Brazil, we observed large chlorotic, necrotic, helical, discontinuous, dark or light-brown lesions with partial detachment of the injured area on the adaxial surface of leaves located in the median and basal portions of the plants. A whitish mycelium mantle covers the lesions on the leaves at the abaxial surface at
more » ... moisture conditions. Using morphological characteristics, Koch's postulates, and phylogenetic analyses of the ITS-5.8S rDNA region, we identified that the fungus causing the lesions on the okra leaves was Thanatephorus cucumeris (Frank) Donk (asexual stage of Rhizoctonia solani Kuhn of the anastomosis group AG-1 ID). This is the first report of T. cucumeris causing web blight on okra in Brazil, and probably in the world. So far, T. cucumeris was described on okra only on post-harvest pods rotting and seedlings' damping off.
doi:10.1590/1808-1657000252016 fatcat:erpkltzvabbntagqecfufxer2u