TABLE CONTENTS

e retained for seed production on the basis of nematode counts taken at the time of immature
harvest, and controlling volunteer ginger and weeds such as crowsfoot (Eluisine indica) that
host the nematode during the non-ginger phase of the rotation.
Distribution of Helicotylenchus multicinctus and their Associated Natural
Enemies in Banana Plantings in Hawaii
Wang, K.-H., C.R.R. Hooks & B. Sipes
Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, 3050 Maile Way,
Honolulu, HI 96822.
Previously, the spiral nematode, Helicotylenchus multicinctus, was not listed as an important
nematode pest of banana (Musa spp.) in Hawaii. The objectives of this study were to
determine the distribution of spiral nematodes inhabiting banana fields in Hawaii and their
natural enemies (e.g. predatory nematodes and nematode-trapping fungi). Twenty-seven
banana farms were surveyed on six major Hawaiian islands. Spiral nematodes were detected
in 17 out of 27 farms surveyed with densities of 220 to 1,427 nematodes per 250 cm 3 soil and
367 to 21,556 nematodes per 10 g dry root weight on banana cultivars with ploidy levels of
AAA (‘Williams’, ‘Chinese Williams’, ‘Bluefields’, and ‘Valery’), AAB (‘Tall Brazilian’,
‘Santa Caterina’), ABB (‘Largo’, and ‘Ice Cream’), and BBB (‘Saba’). The survey revealed
that H. multicinctus is more commonly found in banana than the burrowing nematode,
Radopholus similis. Severely infected banana plants have poor root system and tended to
topple. During this survey, several natural enemies of nematode pests were encountered.
Omnivorous and predatory nematodes, which potentially prey on spiral nematodes, were
found in 93% of the farms surveyed. Although not statistically different, organic farms had
higher counts of omnivorous or predatory nematodes than many conventional banana
plantings. Among the nematode-trapping fungal species observed, Arthrobotrys oligospora,
Monocosporium ellipsosporum, and M. eudermata were the most commonly found
nematode-trapping fungi.
Effects of ced-9 Antisense Expression in Transgenic Tobacco Plants on
Meloidogyne incognita
Yamamoto F. (1), T. Padukkavidana (2), G.W. Polack (1) & A. Calderón-Urrea (1)
(1) Department of Biology, California State University, Fresno, Fresno, CA, USA, 93740; (2) Graduate School,
Yale University, New Haven, CT, USA, 06511
As an alternative to using pesticides to control nematodes, we are exploring the possibility of
using transgenic plants expressing nematode programmed cell death genes to control
nematode infestation. We hypothesize that knocking down ced-9-like genes of plant parasitic
nematodes using antisense RNA, will limit their proliferation and/or reproduction. Provided
that there are similar ced-9 sequences in parasitic nematodes, we predict that plants
containing a reverse (antisense) ced-9 gene would stimulate the programmed cell death
pathway of parasitic nematodes, resulting in plant protection. We generated homozygous
transgenic tobacco plants expressing either ced-9-F (ced-9 gene clones in the sense
orientation) or ced-9-R (ced-9 gene cloned in the antisense orientation). Selected ced-9-R and
ced-9-F transgenic tobacco lines, both expressing high levels of the transgene (as determined
by competitive RT-PCR) and no other phenotypic effect, were tested for resistance to
5 th International Congress of Nematology, 2008 211