Submitted to: Hortechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/7/2005
Publication Date: 7/1/2005
Citation: Meyer, S.L., Zasada, I.A., Tenuta, M., Roberts, D.P. 2005. Application of a biosolid soil amendment, calcium hydroxide, and streptomyces sp. for management of root-knot nematode on cantaloupe. Hortechnology 15(3): 635-641. Interpretive Summary: Plant-parasitic nematodes are microscopic worms that cause ten billion dollars in U.S. crop losses annually. Root-knot nematodes are among the most destructive species. One problem facing growers is the lack of safe and effective methods for controlling nematode-induced crop losses. Because of this need for new management agents, a soil amendment called N-Viro Soil and the naturally occurring bacterium Streptomyces were tested for the ability to control root-knot nematodes on cantaloupe roots. The results indicated that N-Viro Soil can cause a large reduction in egg populations on the plant roots, but the bacterium was not effective. The results are significant because they demonstrate that the amendment can be lethal to root-knot nematodes in the soil. This research will be used by scientists developing environmentally safe methods for managing diseases caused by nematodes.
Technical Abstract: The biosolid soil amendment N-Viro SoilTM (NVS) and a Streptomyces sp. isolate (99-60) were tested for effects on root-knot nematode (RKN: Meloidogyne incognita (Kofoid & White) Chitwood) egg populations on cantaloupe (Cucumis melo L.). Application of NVS at 3% (dry w/w) in the soil mixture resulted in significant (P = 0.01) suppression of RKN egg numbers on cantaloupe roots compared to all other treatments, including 1% NVS and untreated controls. Ammonia accumulation was higher with the 3% NVS amendment than with any other treatment. Adjustment of soil pH with calcium hydroxide Ca(OH)2 to the same levels that resulted from NVS amendment did not suppress nematode populations. When cultured in yeast-malt extract broth and particularly in nutrient broth, Streptomyces 99-60 generally produced compounds that reduced RKN egg hatch and activity of second-stage juveniles. However, when this isolate was applied to soil and to seedling roots, no suppression of RKN egg populations was observed on cantaloupe roots. Combining Streptomyces 99-60 with NVS or Ca(OH)2 did not result in enhanced nematode suppression compared to treatments applied individually. The results indicated that NVS application was effective at suppressing RKN populations through the accumulation of ammonia to levels lethal to the nematode in soil.