TABLE CONTENTS

Possible Mechanisms of Action of an Endophytic Fusarium Isolate toward
the Rice Root-knot Mematode Meloidogyne graminicola
Le, H.T.T (1), J.L. Padgham (2) & R.A Sikora (1)
(1) Institute of Crop Science and Resource Conservation (INRES9; Department of Nematology in Soil
Ecosystems, University of Bonn, Nussallee 9, Bonn 53115, Germany; (2) Climate change consultant, the World
Bank, Washington DC, USA
Many studies have been carried out to investigate the interaction between a soilborne plant
pathogen, its microbial antagonistist(s), and the host plant on non-graminaceous species,
while there has been relatively litle research done on such complex interrelationships existing
in cereal crops, such as rice. A biological control system for the rice root knot nematode
Meloidogyne graminicola was recently developed at the University of Bonn, using an
endophytic Fusarium isolate that was isolated from a rice growing region of Vietnam. This
Fusarium isolate demonstrated good antagonistic potential against M. graminicola by
reducing gall formation and juvenile penetration by upto 50%. In vitro experiment showed
that secondary metabolites produced by this endophytic fungus caused nematode mortality by
up to 95% after 72 hours exposure compared with nematode not exposed to fungal
metabolites. Secondary metabolites also significantly inhibited egg hatching of the nematode.
In vivo experiments demonstrated that the fungus interfered with nematode reproduction by
reducing the number of females and number of eggs per female, thus reducing nematode
populations in the root over time.
Effects of Increasing Inoculation Levels of in vitro Produced ‘Candidatus’
Pasteuria usgae’ on Belonolaimus longicaudatus on Turf
Luc, J.E. (1), W.T. Crow (1), R. Giblin-Davis (2), R. McSorley (1) & J. Sartain (3)
(1) Entomology and Nematology Department, University of Florida, Gainesville, FL 32611; (2) Ft. Lauderdale
Research and Education Center, University of Florida, Davie, FL 33314; (3) Soil and Water Science
Department, University of Florida, Gainesville, Florida 32611.
Experiments were conducted to evaluate the effects of increasing inoculation rates of
‘Candidatus Pasteuria usgae’ endospores per cubic centimeter of soil on Belonolaimus
longicaudatus populations on turfgrass in greenhouse culture. Treatments were endospore
rates of 0; 28,000; 56,000; or 140,000 endospores/cm 3 of sand with four replications at two
observation dates. Endospores in liquid suspension (100 ml) were applied to 1,430 cm 3 of
sand, mixed, and then potted. ‘Penncross’ creeping bentgrass was seeded, into pots, allowed
to germinate, and then establish for 10 days prior to inoculation of 900 mixed life stages of B.
longicaudatus/pot. Nematode samples were collected from sixteen pots at 28 days and 56
days after nematode inoculation, respectively by removing a single core (7.62-cm-diam., 10-
cm-deep) from the center of each pot. Nematodes were extracted from these cores by
centrifugal-flotation and counted. Effects of endospore level on number of B. longicaudatus
were quantified using regression analysis. Belonolaimus longicaudatus populations were
reduced with increasing levels of endospores (P = 0.007). At the 140,000 endospores/cm 3 B.
longicaudatus populations were reduced by 33 and 45 % at 28 and 56 days, respectively
compared to the 0 endospore rate.
5 th International Congress of Nematology, 2008 296