Summary: Effect of Short-Chain Fatty Acids and Soil Atmosphere on
Claire F. McElderry,2
and Jose´ A. Amador2
Abstract: Short-chain fatty acids can be produced under anaerobic conditions by fermentative soil microbes and have nematicidal
properties. We evaluated the effects of butyric and propionic acids on death and recovery of stunt nematodes (Tylenchorhynchus
spp.), a common parasite of turfgrass. Nematodes in a sand-soil mix (80:20) were treated with butyric or propionic acid and
incubated under air or N2 for 7 days at 25 °C. Amendment of soil with 0.1 and 1.0 µmol (8.8 and 88 µg) butyric acid/g soil or 1.0
µmol (74 µg) propionic acid/g soil resulted in the death of all nematodes. The composition of the soil atmosphere had no effect
on the nematicidal activity of the acids. Addition of hydrochloric acid to adjust soil pH to 4.4 and 3.5 resulted in nematode mortality
relative to controls (41% to 86%) but to a lesser degree than short-chain fatty acids at the same pH. Nematodes did not recover after
a 28-day period following addition of 10 µmol butyric acid/g soil under air or N2. Carbon mineralization decreased during this
period, whereas levels of inorganic N and microbial biomass-N remained constant. Short-chain fatty acids appear to be effective in
killing Tylenchorhynchus spp. independent of atmospheric composition. Nematode mortality appears to be a function of the type and
concentration of fatty acid and soil pH.
Key words: butyric acid, carbon mineralization, fatty acid, nematicide, nematodes, propionic acid, Tylenchorhynchus spp.
Nematode parasitism of turfgrass roots impairs ability
to absorb water and nutrients, resulting in disease
symptoms that include wilting, chlorosis, and stunting.