03208nam a2200313 a 450000100080000000500110000800800410001910000270006024500980008726000160018530000110020150001030021252022640031565000130257965000210259265000200261365000140263365000220264765000110266965000180268065000250269865000260272365000150274965300370276465300250280165300260282665300230285265300190287514985562023-08-25       1997    bl uuuu  m   00u1 u    #d1 aRITZINGER, C. H. S. P.  aManaging root-knot nematodes in greenhouse and microplot experiments with organic amendments.  a1997.c1997  a153 p.  aThesis (Doctor odf Philosophy) - University of Florida, Gainesville. Orientation: Robert McSorley.  aEight different organic amendments were utilizend to suppress root-knot nematodes (Meloidogyne incognita and M. arenaria) in several experiments. In the greenhouse, inoculation of two-week-old seedlings of 'Clemson Spineless' okra (Hibiscus esculentus) provided the best conditions for building up root-knot nematode populations and studing populations and studying populations dynamics. Plant growth and nematode supression were higher when amendment was placed on soil surface rather than incorporated into soil. In another study,castor (Ricinus communis) and velvetbean (Mucuna deeringiana) soil amendments resulted in better plant groth and nematode suppression than collard (Brassica oleracea), zinnia elegans, sesame (Sesamum indicum), and 'SX-17' sorghum-sudangrass (Sorghum bicolor x S. sudanense). For velvet bean and castor amendments, a rate of 5g per 560cm3 of M. arenaria infested soil was best for plant growth and nematod suppression. Irrigation frequency,time for amendment decomposition, and inoculum density were also important factors affecting plant response. However, it cannot be generalized that amendments with low C/N ratios will always suppress nematodes and improve plant growth if conditions of soil moisture, temperature, plant host, and nematode species are not kept constant. A thee-year microplot experiment with perennial peanut (Arachis glabrata) hay and yard-waste compost (mainly woodchips) revealed greater treatment responses with peanut hay at low or high nematode (M.arenaria) levels, propably because this amendment had a lower C/N ratio. Root-Knot nematodes impaired nutrien uptake, thus high residual levels of nutrientes were registered in soil under the high nematode treatment. Nutrient analysis within okra plants varied among plant tissue and plant growth stage. Residual levels of nutrients in soil affected growth of a subsequent rye (Seclae cereale) cover crop, and high levels of root-knot nematodes affected dynamics of the stubby-root nematode (Paratrichodorus minor). Plant growth and nematode suppression were demonstrated with use of organic amendments, with low C/N ratio and a non-host crop, could be adopted for more effective use of the amendment in supressing nematodes and improving plant growth.  aNematoda  anematode control  aAdubo Orgânico  aCorretivo  aDoença de Planta  aEstufa  aMeloidoginose  aMeloidogyne Arenaria  aMeloidogyne Incognita  aNematóide  aGreenhouses: Corrective dressing  aMeloidogyne aremaria  aMeloidogyne incognito  aOrganic amendments  aPlant diseases