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Quantifying the Spatial and Temporal Variations of Plant-Parasitic Nematodes Associated with Corn in Ohio

Abasola Simon: The Ohio State University

<div>The vertical distribution of five plant-parasitic nematodes was examined in two Ohio corn fields, one with a silt loam soil in Wayne county and another with sandy loam in Fulton county. Population densities of <em>Pratylenchus crenatus</em>, <em>P. thornei</em>, <em>Helicotylenchus pseudorobustus</em>, <em>Paratylenchus neoamblycephalus</em>, and <em>Tylenchorhynchus claytoni</em> were determined from soil samples taken during corn growth stages VE to V10 at 10 cm increments to a depth of 70 cm. <em>P. crenatus</em> and <em>P. thornei</em> predominantly inhabited the top 40 cm of soil and occurred at significantly higher densities between growth stages V6 to V10, particularly in the root fraction. The highest population densities of <em>H. pseudorobustus</em> were found in the upper 20 cm of the soil profile at the Fulton location, and predominantly in the top 40 cm at the Wayne location at all growth stages monitored. <em>P. neoamblycephalus</em> was also detected at both locations, with the highest population densities at the 20 cm depth in Wayne, regardless of growth stage, and at the 40-60 cm depth in Fulton at the V3-V4 growth stages. <em>T. claytoni</em> was recovered from the Fulton field only, predominantly inhabiting the top 40 cm of the soil profile where counts were generally highest between growth stages V6 to V7. Our findings suggest that the depth and growth stage at which samples are collected to estimate nematode population density should vary with the nematode species in question.</div>