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United States Department of Agriculture

Agricultural Research Service

Title: Evaluation of Verticillium Lecanii Strains Applied in Root Drenches for Suppression of Meloidogyne Incognita on Tomato

item Meyer, Susan

Submitted to: Nematologica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 29, 1997
Publication Date: N/A

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that attack plants and cause seven billion dollars worth of agricultural losses each year in the U.S. Some chemical nematicides used to control these pests may contribute to environmental contamination and toxicity to animals and humans. New management agents are consequently needed for nematodes. Fungi that have potential to kill nematodes were applied to tomato plants to see if fewer nematodes were produced on the plants. For this application, the fungi were mixed in water and then poured around the tomato roots at the time the tomato seedlings were transplanted. The fungi tested did not decrease nematode numbers when applied in this manner. Users of this information include research scientists and industr workers interested in developing management agents for nematodes.

Technical Abstract: Three-week old tomato seedlings were transplanted from sand into 10-cm diameter pots (538 ml volume). Each pot contained 598 g loamy sand treated with either 1,000 or 5,000 Meloidogyne incognita eggs. Five strains of the fungus Verticillium lecanii were individually applied in root drenches to the tomato plants at the time of transplanting, at an application rate of about 0.08% (dry weight fungus/dry weight loamy sand). The strains were a wild type strain and four mutants induced from that strain. Controls were treated with water only or with autoclaved (nonviable) fungus. After 45 days, the plants were harvested, and egg numbers per pot, root infection ratings, root lengths, and shoot dry weights were determined. Egg numbers counted from fungus-treated plants did not differ significantly from the water controls. Application of autoclaved wild type strain to pots treated with 5000 eggs resulted in an infection rating significantly higher than that from plants treated with water only. The former plants also had lower shoot weights than water control plants.

Last Modified: 3/29/2015
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