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United States Department of Agriculture

Agricultural Research Service

Title: Biological Control of Root-Lesion Nematodes in Alfalfa by Streptomyces

Author
item SAMAC, DEBORAH

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

Technical Abstract: Root-lesion nematodes (RLN) (Pratylenchus penetrans) parasitize roots of many important crops. In alfalfa, RLN feed on fibrous roots and nodules, reducing plant stands and yield. The potential of antibiotic-producing strains of Streptomyces to reduce damage to alfalfa by RLN was evaluated in growth chamber studies. Seed from three germplasms (resistant, moderately resistant, and susceptible to RLN) was planted in a soil:sand mix in "cone-tainers." Streptomyces was applied around seed at planting at 1 million colony forming units/g soil and RLN were added to soil around alfalfa roots. Streptomyces colonized the alfalfa rhizosphere, and populations on roots and in soil were stable over 14 wk. In two separate experiments, treatment with Streptomyces reduced by 5-fold the number of RLN/g dry fibrous roots on all varieties 12 wk post inoculation. Populations of RLN in fibrous roots of the susceptible and moderately resistant plants were reduced with Streptomyces treatment to levels not significantly different from populations in untreated resistant plants. The low number of nematodes was found in roots of the resistant variety treated with Streptomyces. These results indicate that Streptomyces treatment has the potential to control RLN in alfalfa and augment the benefits derived from genetic resistance.

Last Modified: 8/19/2014
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