TABLE CONTENTS

TOPIC FOUR – PLANT-PARASITIC NEMATODES: ROOTS
Occurrence of Rice-root Nematode, Hischmaniella oryzae among 11 Rice
and10 Weed Selections
Anwar, S. (1), M.V. McKenry (2) & S.I. Yasin (3)
(1) Department of Plant Pathology, University of Agriculture, Faisalabad, Pakistan; (2) Department of
Nematology, University of California, Riverside, USA; (3) Rice Research Institute, Kala-Shah-Kaku, Pakistan.
The occurrence of rice-root nematode, Hirschmaniella oryzae in roots of 11 rice, Oryza
sativa, selections and 10 weed species belonging to 7 families was recorded during 2006-07.
Nematode density in composite root samples was determined by a Modified Sieving-
Baermann Funnel technique. Nematode root populations varied greatly among rice selections
and weeds. Ten rice cultivars including Super Basmati, Basmati-198, Basmati-2000,
Basmati-370, Basmati-385, KSK-133, KSK-201, KSK-282, IR-6, and IR-9 exhibited
nematode population levels in excess of the damage threshold level (5-30 nematodes per g of
root). Only Basmati Pak supported nematode populations below the threshold level. The
Basmati selections supported varying levels of nematodes. Basmati-370, Basmati-385, and
Super Basmati supported significantly greater nematode populations than three other Basmati
selections. Two IR selections supported the same number of nematodes but significantly
fewer than KSK selections. Six weed species including Echinochloa colona, E. glabrescens
(poaceae), Chenopodium album (chenopodiaceae), Cyperus difformis, Rumex dentatus
(polygonaceae), and Scripus maritimus (cyperaceae), supported nematodes at levels similar to
that recovered from rice roots. Four other weed species including Coronopus didymus
(brassicaceae) Marsilea minuta (marsileaceae), Paspalum distichum (poaceae), and
Sphenoclea zeylanica (campanulaceae) were consistently infected by the nematode but at
levels reduced from those found in rice roots. This study indicates that rice-root nematode is
able to infect all commercially grown cultivars and weeds common to Pakistani rice fields.
These results further demonstrate that weed hosts act as a reservoir for over-wintering H.
oryzae.
Pathogenicity and Management of Pratylenchus penetrans on Apple in
Quebec, Canada
Bélair, G., N. Dauphinais & Y. Fournier
Department of Environmental Biology, Adelaide University, South Australia 5000; (2) South Australian
Museum, Adelaide, South Australia 5000
In 2006, three 1-year dwarf-type apple rootstocks were exposed to field estimated densities of
0 (undetectable), 500 (intermediate), and 5000 (high) P. penetrans kg -1 under field microplot
conditions in a split-plot design with eight repetitions. Based on shoot dry weights, growth of
roostocks Bud-9, M-9, and M-26 was reduced by 30 and 36%, 23 and 25%, 14 and 29%
when exposed the intermediate and high P. penetrans densities respectively. Trunk diameters
were also reduced by 31% (Bud-9), 19% (M-9) and 15% (M-26) when exposed the high
density and Bud-9 exhibited a 17% reduction under the intermediate density. From 2004 to
2006, a field experiment was performed to evaluate the potential of a 1- and 2-year cover
cropping to management of P. penetrans densities and assess its incidence on the growth and
production of apple transplants. Cover crops evaluated were forage pearl millet cv.
5 th International Congress of Nematology, 2008 198