TABLE CONTENTS

toxicity tests were conducted over 3, 9, 22 and 52 hours. Abamectin caused 40% paralysis
within 3 hours of exposure to the nematode when compared to the check and reached 99.25%
after 52 hours exposure. A high level of mortality was detected after exposure to Abamectin:
65 to 85% after 3 to 22 and 95% after 52 hours exposure, when placed in tap water.
Abamectin seed treatment therefore would be a highly effective method of controlling the
stem nematode on sugar beet.
Host Ranges of Four Populations of Stem and Bulb Nematode, Ditylenchus
dipsaci in Iran
Fasihi, M. (1), Z. Tanha Maafi (2) & A. Karegar (3)
(1) Islamic Azad University of Damghan; (2) Iranian Research Institute of Plant protection, P.O. Box 1454
Tehran 19395, Iran; (3) Department of Plant Protection, College of Agriculture, Shiraz University
D. dipsaci is widespread in alfalfa fields in Iran and the infection of garlic to D. dipsaci has
been reported from a few regions in recent years. Four populations of D. dipsaci were
collected from alfalfa and garlic plants in west, center, northwest and northeast respectively.
The populations were cultured on monoxenic carrot disk to provide sufficient inoculation
materials. The host ranges of two garlic populations were tested on garlic, onion, faba bean,
common bean, sugar beet, pea and soybean. Alfalfa, Melilotus sp., common bean, clover, and
sainfoin (Onobrychis viciaefolia Scop.) were tested with two alfalfa populations of D.
dipsaci. The plants were inoculated at a rate of 100 D. dipsaci in 10µl of CMC
(Carboxymethyl cellulose) suspension 1% and maintained in growth chamber at 20°C ± 2 for
16-hour light and 8-hours dark period, meanwhile high humidity was provided for all plants
for one week. The plants were harvested after eight weeks (some after four weeks) and the
aboveground parts were examined. The results showed both garlic populations were
multiplied on all plants tested except on soybean, both populations highly multiplied on onion
with reproduction factor (RF) of 30 and 128 for northwest and northeast populations,
respectively, while the RF was 10 and 13 in garlic and 1-2 in faba bean, common bean, sugar
beet and pea. The alfalfa populations showed high reproduction on common bean and the RF
was 4 after four weeks, the RF on alfalfa and Melilotus sp. was 1-1.3 and for clover and
sainfoin