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United States Department of Agriculture

Agricultural Research Service

Title: Development of Techniques to Assay Fungus Culture Broth for Metabolites Toxic to Root-Knot and Soybean Cyst Nematodes

Authors
item Nitao, James
item Meyer, Susan
item Chitwood, David

Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: July 19, 1997
Publication Date: N/A

Technical Abstract: Fungi of potential use for the biological control of plant-parasitic nematodes may reduce nematode populations by secreting toxic metabolites as well as by directly parasitizing hosts. To identify such metabolites, in vitro bioassay techniques were developed to screen fungal cultures for inhibitors of soybean cyst nematode (Heterodera glycines) and root-knot nematode (Meloidogyne incognita) egg hatch. Methods were developed for us of eggs obtained from greenhouse-grown plants and fungal cultures grown in two standard media, potato-dextrose broth and Czapek-Dox broth. Media alone strongly inhibited soybean cyst nematode egg hatch when compared to water. Neither adjustment of pH nor addition of zinc sulfate sufficiently countered the inhibition. This necessitated a dilution of the media prior to being tested or the transfer of the eggs to water after exposure to media. In contrast, root-knot nematode eggs were found to hatch at consistent levels in both media, allowing direct screening of fungal broth after sterile filtration and addition of antibiotics.

Last Modified: 9/1/2014
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