Covid-19 had a large impact on Agricultural Extension programming over the past year.  Work rules have dictated that we have minimal contact with people when possible, and that we wear face masks and social distance around clients.  These circumstances created unique opportunities to be involved in Extension projects that required minimal direct contact with clients.  

This year, plant pathology specialist Dr. Carl Bradley requested soil samples from soybean fields to survey for plant-parasitic nematodes (other than soybean cyst nematodes (SCN)) that can negatively affect soybean yields.  Dr. Bradley also promoted the opportunity to test fields for SCN through a program where the Kentucky Soybean Association was paying the lab fees.  Taking advantage of these opportunities, I sampled 22 producer fields for soybean cyst nematodes and took 8 soil samples for Dr. Bradley’s other parasitic nematode survey.  Ten of the fields sampled for SCN had been sampled previously.  We are still waiting on the results of the fall 2020 samples to see how SCN egg numbers have changed over the 2020 growing season.

Comparing spring 2020 soybean cyst nematode test results with spring 2019 egg numbers typically provided the expected results.  Where soybeans were grown in 2019, SCN egg numbers increased over the growing season, with one exception.  Where corn was grown in 2019, SCN egg numbers decreased over the growing season, with one exception.  This was proof to the participating farmers that growing a non-host crop is an effective tool for reducing soybean cyst nematode numbers in their crop fields.     

Plant pathology specialist Dr. Kiersten Wise requested soil samples from corn fields to survey for plant-parasitic nematodes that might affect corn yields.  Wise was also seeking corn residue samples for North Dakota scientists to use in validating a test that detects some corn disease pathogens on corn crop residues.  I provided Dr. Wise with soil samples from 11 corn fields to test for corn nematodes and 4 corn residue samples for use in the North Dakota National Prediction Tool Modeling Initiative.      

The corn nematode testing program examined soil samples for 8 species of parasitic corn nematodes—Lesion, Spiral, Dagger, Lance, Stunt, Ring, Pin, and Stubby Root nematodes.  Five of these species—Lesion, Spiral, Lance, Stunt, and Pin nematodes were discovered in the Todd County samples.  Lesion and Spiral nematodes were found in all 11 samples, with most risk levels (the odds of a nematode-related yield reduction) ranging from “Non-significant” to “Moderate.”  However, one field had enough Lesion nematodes to have a “Severe” risk of yield reduction.  Stunt nematodes were found in 6 fields, Lance nematodes in 5 fields, and Pin nematodes in 1 field.  Dagger, Ring, and Stubby Root nematodes were not found in any of the Todd County samples.