Submitted to: Soybean Disease Compendium
Publication Type: Book / Chapter
Publication Acceptance Date: August 10, 1999
Publication Date: December 12, 1999
Citation: Hartman, G.L. Red leaf blotch. chapter in compendium of soybean diseases (4th ed).. Soybean Disease Compendium: p.1-99. Technical Abstract: Red leaf blotch has been reported in central to southern Africa. Estimated yield losses of 7 to 37% in approximately 25% of the soybean-producing area of Zambia have been reported, along with 10 to 50% yield losses in Zimbabwe. The fungus causes lesions on foliage, petioles, pods, and stems. Heavily diseased plants defoliate and senesce earlier than normal. Red leaf blotch is caused by Dactuliochaeta glycines (sclerotial state Dactuliophora glycines). Sclerotia from the soil and those that land on leaf surfaces give rise to pycnidia, either on their surfaces or possibly from mycelium. The pycnidia form conidia, which can infect, and sclerotia on leaves can form mycelium that penetrates directly. Within older lesions, both pycnidia and sclerotia develop. No commercial procedures are recommended for the management of red leaf blotch. However, spraying with fungicides, mulching with grass and sawdust, or the use of resistance have been demonstrated experimentally.