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United States Department of Agriculture

Agricultural Research Service

Title: Colonization of Soybean Cyst Nematode by the Fungus Verticillium Lecanii

item Meyer, Susan
item Wergin, William

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 1997
Publication Date: N/A

Technical Abstract: Soybean cyst nematode (SCN) is an economically important pest in soybean-growing areas world-wide. The fungus Verticillium lecanii acts against SCN, decreasing viable egg numbers in Petri dish assays and nematode population densities in greenhouse tests. This light and electron microscope study was conducted to investigate physical interactions occurring between the fungus and SCN. A mutant strain of V. lecanii (selected for benomyl tolerance) was inoculated onto SCN females and cysts produced in root explant cultures. The SCN gelatinous matrix (GM) was colonized; the fungus became so dense in some specimens that the hyphae appeared to replace the GM. Inside females and cysts, areas that would have been occupied by eggs were filled with hyphae, although V. lecanii was not observed penetrating live eggs. This supports the theory that V. lecanii does not act through egg parasitism, but induces egg death and than ncolonizes the dead eggs. The microscopy evidence also indicates that the action of the fungus may, in part, be due to physical occupation of space, thereby precluding normal egg production

Last Modified: 4/22/2015
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