Abstract:
To understand the relationship between natural phys
icochemical properties of soil and
abundance of citrus root nematode (
Tylenchulus semipenetrans
), a survey was conducted
during 2009-2010 in some 37 citrus orchards, in Koh
gilouyeh va Boyerahmad Province,
Iran. Distribution of the citrus nematode was deter
mined by collecting random samples
from the soil and citrus plant roots, extracting an
d enumerating the number of second
stage juveniles, males/100 g of soil and females/5
g of root. The relationships between
nematode population, and the factors of: organic ma
tter content, Nitrogen (N),
Phosphorus (P), Potassium (K), organic carbon, Calc
ium Carbonate, soil texture,
Electrical Conductivity (EC) and pH were determined
. Increase in nematode population
density was observed by increasing soil saturation
percentage (up to 43%), and by an
increase in soil silt, sand, P, K and organic carbo
n, but by an increase in soil salinity,
Calcium Carbonate, total Nitrogen and the amount of
clay in soil, the nematode
population decreased. Maximum nematode population d
ensity was recorded in a loamy
soil texture. The most suitable soil pH for nematod
e activity was found almost seven while
either an increase or decrease in soil pH, resulted
in a decrease in nematode population.
The number of second stage juveniles ranged from 58
to 2,730/100 g of soil while females
were present by 11 to 331 individuals/g of root res
pectively. About 62% of the studied
orchards were infested with
T
.
semipenetrans
.
