TABLE CONTENTS

The Effect of Different Levels of Population Densities of Heterodera filipjevi
(Madzhidov, 1981) Stelter, 1984 on Bread Wheat under Microplot
Conditions
Hajihasani, A. (1), Z. Tanha Maafi (2), S. Rezaee (3) & M. Ghalandar (4)
(1) Young Researchers Club, Islamic Azad University, Arak, Iran; (2) Iranian Research Institute of Plant
protection, P.O. Box 1454 Tehran 19395, Iran; (3) Plant Pathology Department, Faculty of Agriculture and
Natural Resources, Science and Research Branch, Islamic Azad University, Tehran, Iran; (4) Agricultural and
Natural Resources Research Center of Markazi, Iran
The three species of cereal cyst nematodes Heterodera avenae Wollenweber, 1924, H.
filipjevi (Madzhidov, 1981) Stelter, 1984 and H. latipons Franklin, 1969 are considered to be
the most economically important species on wheat compared others in the H. avenae
complex. H. filipjevi and H. latipons are widely distributed in Iran, while H. avenae has
limited distribution on wheat. To determine the impact of different levels of population
densities on wheat four levels of population densities of H. filipjevi 2.5, 5, 10 and 20 eggs and
J2s /g -1 soil as initial populations were tested on wheat cultivar Sardari in microplot under
natural field conditons arranged as a Completely Randomized Design replicated seven times.
The results showed increasing the H. filipjevi initial population significantly reduced several
growth parameters of wheat (including plant height, number of tillers, spike height, dry root
weight, aerial dry weight, and grain yield) compared to untreated control. The final
population increased with increasing initial population while the reproduction factor (RF –
final population/initial population) reduced by increasing the initial population but it was still
greater than one in all treatments. The regression analysis showed significant negative
relationship between the initial populations and grain yield, and grain yield was reduced even
at lowest population density and reached a maximum reduction of 47% at population density
of 20 egg and J2s/ g -1 soil.
Destroying Melodogyne chitwoodi in Potato before Processing
Ingham, R.E. & N.M. Wade
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
Columbia root-knot nematode (Meloidogyne chitwoodi, CRKN) infects potato tubers and
causes quality defects such as galling of the external surface and brown spots surrounding the
egg masses of adult females inside the tuber. Both symptoms are considered quality defects
by the potato industry and can cause crop rejection. Furthermore, CRKN is considered a
quarantined pest by several countries and infested tubers are not allowed entry. For example,
in 2005 57 containers (approximately 1,140 MT) of chipping potatoes from the United States
were denied entry into South Korea due to the presence of CRKN and the potatoes were
returned. This resulted in lost revenue to the growers and a loss of product needed for
processing potato chips in South Korea. Although CRKN is aggressively managed a
probability exists that a small percentage of tubers may be lightly infested. An alternative to
re-exportation of potatoes when low amounts of CRKN are detected is to destroy CRKN in
infested potato tissues before processing. Several procedures were tested as destruction
protocols for eliminating live CRKN from potato tissues by treating either whole tubers or
peels, placing the tissues on a mist chamber and daily examining any recovered nematodes
for viability. Exposure of CRKN–infested tissues to chlorine in the form of bleach at
concentrations up to 25,000 ppm Cl was ineffective. Boiling potato peels and water
5 th International Congress of Nematology, 2008 204