Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 29, 1997
Publication Date: N/A
Technical Abstract: Red leaf blotch, caused by Dactuliochaeta glycines, and leaf rust, caused by Phakopsora spp., are two diseases that have not made any impact on U.S. soybean production. Red leaf blotch, which occurs in southern Africa and recently has been reported in west Africa, has the potential to become one of the major soybean pathogens in the U.S. if it were to become established. The fungus produces sclerotia that either germinate and infect plants directly or produce pycnidia and infectious spores. There are at least two species of Phakopsora that cause leaf rust. The first is P. pachyrhizi which occurs in S.E. Asia and Australia and is common to some of their soybean production areas. The other species is P. meibomiae which occurs in the Caribbean and Central and South American countries, and was recently reported in Hawaii. The fungi that cause leaf rust produce urediniospores that are air-blown and can spread over a wide geographical area. Like red leaf blotch, leaf rust has the potential to devastate U.S. soybean production because the fungus produces abundant spores that can be dispersed rapidly over a wide geographical area. If either fungus enters into the U.S. soybean production areas, leaf rust has the greater potential to be more widespread than red leaf blotch which will probably be more localized.