FUSARIUM-SOLANI FROM ASCOSPORES OF NECTRIA-HAEMATOCOCCA CAUSES SUDDEN-DEATH SYNDROME OF SOYBEAN

This is the first report of a teleomorph connection for isolates of Fu sarium solani that infect soybean. Nectria haematococca isolated from roots of soybean plants with sudden death syndrome proved to be the as coma stage of F. solani. A single ascospore culture IN-2X-11A from IN- 2X-11 produced sporodochia with masses of blue macroconidia and essent ially no microconidia. Another single ascospore culture IN-2X-11B from IN-2X-11 did not produce macroconidia, but it did produce the perfect state and microconidia. Hypocotyl inoculation of soybeans with macroc onidia plus mycelia of IN-2X-11A caused severe foliar symptoms typical of sudden death syndrome. In contrast, no foliar symptoms of sudden d eath syndrome developed in plants inoculated with microconidia plus my celia. Pathogenicity of the N. haematococca isolate producing abundant F. solani macroconidia has been stable in inoculation tests since 198 9, and it is more virulent than several other Indiana isolates of F. s olani from soybean plants with severe sudden death syndrome.