Symptoms of the bacterial disease, Goss’s Wilt, have been reported in corn fields yet again this season. Reported hot spots in 2012 include west of Altona to south of Winkler. This disease causes a leaf and vascular blight which can result in severely wilted plants and yield loss.
Initial symptoms include water-soaked lesions on the leaves later accompanied by “freckling”. Symptomatic leaves often appear shiny due to the bacterial exudate present on the leaf surface. Plants that are damaged by hail, wind, or sand-blasting are susceptible to infection by the bacteria. Wet weather and high humidity favour development of the disease, although disease spread under hot, dry conditions has also been documented.
Management of Goss’s Wilt includes tillage, crop rotation, removal of grassy weed hosts (green foxtail, barnyard grass, etc.), and genetic resistance. Fungicides are not effective against this disease as it is caused by a bacterial pathogen. Genetic resistance is the primary management strategy, and therefore affected growers should contact their seed providers about resistant corn hybrids.
Above information taken from the August 24th edition of the Manitoba Insect & Disease Update.