Comparison of Methods and Corn Root Types for Efficient Extraction of Endoparasitic Nematodes

Authors

Jae L. Behn, University of Nebraska-LincolnFollow

Date of this Version

5-2012

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professor Tamra A. Jackson. Lincoln, Nebraska: May, 2012

Copyright 2012 Jae L. Behn

Abstract

Endoparasitic nematodes annually reduced the yield of corn in the United States. Pratylenchus spp. and Hoplolaimus spp. are endoparasitic nematode genera that parasitize corn in the Midwest. Previous research has shown nematode population densities to be highly variable and extraction methods may not provide consistent results. In order to determine more consistent and time efficient results, comparisons were made between four standard nematode extraction techniques for preferences of nematode genera for extraction method, corn root type, and extraction time. The extraction methods evaluated were aeration-incubation, a modified Baermann funnel, Seinhorst’s mister, and shaker incubation. Research plots were established at two Nebraska locations in 2009 and 2010 with documented histories of high population densities of these endoparasitic nematode genera. Nematodes were extracted from six root types on four extraction methods for 3, 5 and 7 days in a complete factorial treatment design. In 2009, Pratylenchus spp. were best extracted from the first set of anchor roots on the Baermann funnel (p < 0.0001) or in the aerated incubation. Hoplolaimus spp. had the greatest recovery from seminal roots on the Baermann funnel in 2009 (p < 0.0001). The mist extraction method did not have consistent results in 2009. For 2010, fine feeder roots in mist or aerated incubation had the greatest recovery of both genera of endoparasitic nematodes (p < 0.0001). In most comparisons, 3-5 days of incubation was sufficient to extract at least 50% of the 7 day population density. For most root types, extraction timings, and nematode genera, the shaker method yielded the fewest nematodes per gram dried root (p < 0.0001). Based on these results, it can be concluded that nematode extraction efficiency varies by genus for root type and extraction method.

Advisor: Tamra A. Jackson