A survey was conducted to determine the frequency and mean densities of
plant-parasitic nematodes associated with cotton crop (Gossypium hirsutum L.)
after the harvesting season 2008 in Syria. Results showed that twelve genera of
plant-parasitic n
ematodes were found associated with cotton crop roots. The
distribution of nematode genera varied between the Syrian governorates,
Pratylenchus spp., Meloidogyne spp. and Rotylenchulus infect most cotton fields
in all syrian governorates. The distribution was relatively uniform between the
governorates. They occurred in 80.7%, 46.6% and 32.95%, respectively, of
tested fields with an average density of 137.2, 59.6 and 574.3 juveniles/100 cm3
soil, respectively. meanwhile, the genus Tylenchorhynchus was found in central
region only. Rotylenchulus was more prevalent in the heavier soils, but
Meloidogyne. was not influenced by soil type. The other nematode genera
detected in this survey were less frequent, their frequency of occurrence were
for Hoplolaimus (19.3%), Scutellonema (31.8%), Tylenchorhynchus (31.8%),
Helicotylenchus (30.7%), Rotylenchus (36.4%), Tylenchus (18.2%), Xiphinema
(3.4%).
Monthly population fluctuations of plant parasitic nematode population
associated with root of cotton in central province fields in Syria were studied
over a 2-year period 2008-2009. In both years, the differences between monthly
samples were not
significant. Average of nematode population density in soil
decreased after sowing (May) and near the end of the season (at harvest) in
both years and in all of the central province fields, then the numbers of
nematode increased slowly again in June to reach a peak at mid-season (July).
Ghab region had the higher population density (1180.8 juveniles/100cm3 soil).
An increase in numbers of nematode in soil was accompanied with a decrease
in number in roots. Negative correlation was observed between average of the
initial population density and reproduction factor. Pratylenchus, Meloidogyne
incognita, Rotylenchulus, Tylenchorhynchus were dominant nematode species
in these fields. Also, the infestation of the first three nematode species was not
uniform.
