Potential Pathogenicity of Pin Nematode on Soybean.

Soybeans are one of the most important economic and agronomic crops produced in Ohio. It is important to identify yield limiting pathogens and pests of this valuable crop in order to keep production in line with demand. There are many nematodes that are known to feed on the roots of soybean, but new pathogens and pests are always emerging. Through a statewide survey of nematodes in Ohio soybean production, the smallest of the plant parasitic nematodes, the pin nematode (Paratylenchus spp.) was found in many fields. Pin nematode has never been officially documented in Ohio.  Furthermore, it is unknown whether or not pin nematode is a pathogen to soybean. The objectives of this research are to 1.) Examine the distribution of pin nematode in Ohio, and 2.) Determine the pathogenicity of pin nematode on soybean. A statewide survey of pin nematodes was conducted in 2013-2015.  Pin nematode was identified and quantified from approximately 600 soil samples collected from over 200 farms throughout Ohio.  A further identification of the nematode to the species level will be accomplished by characterization of the morphometric parameters. To confirm the correct species identification PCR analysis will also be performed on pure cultures of pin nematode.  Once the species is identified Koch’s postulates will be performed with on soybean roots grown in the greenhouse to determine pathogenicity on soybean by observing direct feeding on soybean roots. For the 2013 data across all the districts sampled the pin nematode was found in moderate thresholds (101-500) in 53% of the fields and in the very severe damage thresholds (>1,000) in about 17% of the fields. The results for 2014 being presented across the sampled fields were slightly less dramatic with 16% and ~5% of fields containing moderate and severe pin populations respectively. If the pin nematode is found to be a pathogen of soybean, with its presence in Ohio soybean fields it will be crucial to identify management strategies to fight this potential disease causing parasite and to institute preventative measures so that a compounding, synergistic effect with other pathogens cannot contribute to further yield loss.