TABLE CONTENTS

and compensated for 75% of yield loss sustained by the non-AMF G. pallida-infested plants.
Acceleration of the early G. pallida hatch in the field in response to AMF inoculation of
potato tubers enhanced the efficacy of the nematicide aldicarb by significantly reducing
nematode invasion and multiplication in roots by almost 40% as compared to non-AMF
plants. Despite the increased amount of phosphate in the agricultural soils, high levels of
AMF colonisation were detected, suggesting that PCN control by AMF inoculation can be
feasible for field-grown potatoes.
This research has undoubtedly contributed to a better understanding of the complex
interrelationships between potato plants, PCN and AMF. More importantly, it has opened up
novel avenues in PCN management by applying AMF as part of an integrated PCN
management strategy.
Effects of Selected Rhizosphere Microorganisms and Carbon on Soybean
Cyst Nematode Population Density and Reproduction in Different Tillage
Regimes
Donald, P.A. (1), D.D. Tyler (2) and I. Abdi (3)
(1) ARS USDA, MSA, Jackson, TN 38301. (2) University of Tennessee - WTREC, Jackson, TN 38301,
and (3) currently Biology Department, Lane College, Jackson, TN 38301
Soybean cyst nematode (SCN) population density can be influenced by tillage practices. Data
were collected over two growing seasons on total and active bacteria, total and active fungi,
and protozoans (amobae, flagellates, ciliates) in the soybean rhizosphere to determine
whether the levels of these organisms were related to differences in SCN population density
and reproductive rate under different tillage regimes. Data were also collected on the levels of
soil carbon in the tillage regimes. In 2006 and 2007 the population density of SCN was
highest in treatments which had been tilled since 1979 (long-term tilled) and also in
treatments which had been tilled for the last four years but previously were no-tilled. The
highest levels of total bacteria were found in the long term tilled and no-tilled for the last four
years (previously tilled) treatments. The long term no-till treatments had the lowest levels of
total bacteria but the highest levels of flagellates. The SCN reproductive rate during this
study was highest in the treatments which had been tilled since 1979. Levels of active
bacteria, total fungi, active fungi, cilliates and amobae were similar in all treatments. SCN
reproduction (Pf/Pi) was less than 1 in all treatments except the long term tilled plots in 2007
due to drought conditions.
5 th International Congress of Nematology, 2008 256